Patent Publication Number: US-2022211383-A1

Title: Systems and methods for treating aneurysms

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The field of the invention generally relates to embolic devices for filling spaces in the vascular system, including cerebral aneurysms or left atrial appendages. In some cases, the embolic devices may be used to embolize native vessels. 
     Description of the Related Art 
     An embolic device may be used as a stand-alone device to occlude and aneurysm, or may be used with an adjunctive device or material. 
     SUMMARY OF THE INVENTION 
     In one embodiment of the present disclosure, an apparatus for treating an aneurysm in a blood vessel includes an occlusion element configured to be releasably coupled to an elongate delivery shaft and having a distal end, a proximal end and a longitudinal axis extending between the distal end and the proximal end, the occlusion element including an inverted mesh tube having an outer layer and an inner layer, the outer layer transitioning to the inner layer at an inversion fold, the inversion fold defining a first inner diameter, the inner layer defining a maximum inner diameter, and the outer layer defining a maximum outer diameter, the maximum inner diameter and the maximum outer diameter both residing within a first plane transverse to the longitudinal axis, the first inner diameter residing within a second plane transverse to the longitudinal axis. 
     In another embodiment of the present disclosure, an apparatus for treating an aneurysm in a blood vessel includes an occlusion element configured to be releasably coupled to an elongate delivery shaft and having a distal end, a proximal end, and a longitudinal axis extending between the distal end and the proximal end, a occlusion element configured to be delivered in a collapsed configuration through an inner lumen of a delivery catheter, the inner lumen having a proximal end and a distal end, the occlusion element further configured to expand to an expanded configuration when advanced out of the distal end of the inner lumen of the delivery catheter and into the aneurysm, the occlusion element including an inverted mesh tube having an outer layer and an inner layer, the outer layer transitioning to the inner layer at an inversion fold located at or adjacent the distal end of the occlusion element, the inversion fold defining an inner diameter, the occlusion element further including a maximum outer diameter, wherein the inner diameter is between about 35% to about 85% of the maximum outer diameter, and wherein an outer diameter of the occlusion element increases along the longitudinal axis to the maximum outer diameter. 
     In another embodiment of the present disclosure, an apparatus for treating an aneurysm in a blood vessel includes an occlusion element configured to be releasably coupled to an elongate delivery shaft, the occlusion element including a cover having a mesh material and configured to be delivered in a collapsed configuration through an inner lumen of a delivery catheter, the inner lumen having a proximal end and a distal end, the cover further configured to expand to an expanded configuration when advanced out of the distal end of the inner lumen of the delivery catheter and into the aneurysm, wherein the cover includes a diameter that is greater than the diameter or maximum transverse dimension of a neck portion of the aneurysm, and wherein the cover includes a distal concavity configured to face away from the neck portion of the aneurysm, and a first tubular mesh having a first end, a second end, a wall and a lumen, the first end and the second end of the first tubular mesh coupled to a central portion of the cover such that an intermediate portion of the first tubular mesh between the first end and the second end includes a substantially 180 degree turn, the intermediate portion of the first tubular mesh extending from the distal concavity of the cover, wherein the intermediate portion of the first tubular mesh has a collapsed configuration configured to be delivered through the inner lumen of the delivery catheter, and wherein the intermediate portion of the first tubular mesh is configured to expand to an expanded configuration when advanced out of the distal end of the inner lumen of the delivery catheter an into the aneurysm. 
     In another embodiment of the present disclosure, an apparatus for treating an aneurysm in a blood vessel includes an occlusion element configured to be releasably coupled to an elongate delivery shaft, the occlusion element including a cover having a mesh material and configured to be delivered in a collapsed configuration through an inner lumen of a delivery catheter, the inner lumen having a proximal end and a distal end, the cover further configured to expand to an expanded configuration when advanced out of the distal end of the inner lumen of the delivery catheter and into the aneurysm, wherein the cover includes a diameter that is greater than the diameter or maximum transverse dimension of a neck portion of the aneurysm, a first tubular mesh having a first end, a second end, a wall and a lumen, the first end and the second end of the first tubular mesh coupled to a central portion of the cover such that an intermediate portion of the first tubular mesh between the first end and the second end includes a substantially 180 degree turn, the intermediate portion of the first tubular mesh extending from the distal concavity of the cover, wherein the intermediate portion of the first tubular mesh has a collapsed configuration configured to be delivered through the inner lumen of the delivery catheter, and wherein the intermediate portion of the first tubular mesh is configured to expand to an expanded configuration when advanced out of the distal end of the inner lumen of the delivery catheter an into the aneurysm, and a second tubular mesh having a first end, a second end, a wall and a lumen, the first end and the second end of the second tubular mesh coupled to a central portion of the cover such that an intermediate portion of the second tubular mesh between the first end and the second end includes a substantially 180 degree turn, the intermediate portion of the second tubular mesh extending from the distal concavity of the cover, wherein the intermediate portion of the second tubular mesh has a collapsed configuration configured to be delivered through the inner lumen of the delivery catheter, and wherein the intermediate portion of the second tubular mesh is configured to expand to an expanded configuration when advanced out of the distal end of the inner lumen of the delivery catheter an into the aneurysm. 
     In yet another embodiment of the present disclosure, an apparatus for treating an aneurysm in a blood vessel includes an occlusion element configured to be releasably coupled to an elongate delivery shaft, the occlusion element including a cover having a mesh material and configured to be delivered in a collapsed configuration through an inner lumen of a delivery catheter, the inner lumen having a proximal end and a distal end, the cover further configured to expand to an expanded configuration when advanced out of the distal end of the inner lumen of the delivery catheter and into the aneurysm, wherein the cover in its expanded configuration has a transverse dimension that is greater than a maximum transverse dimension of a neck portion of the aneurysm, and a first tubular mesh having a first end, a second end, a wall and a lumen, the first end and the second end of the first tubular mesh coupled to a central portion of the cover such that an intermediate portion of the first tubular mesh between the first end and the second end includes a substantially 180 degree turn, the intermediate portion of the first tubular mesh extending distally from the central portion of the cover, wherein the intermediate portion of the first tubular mesh has a collapsed configuration configured to be delivered through the inner lumen of the delivery catheter, and wherein the intermediate portion of the first tubular mesh is configured to expand to an expanded configuration when advanced out of the distal end of the inner lumen of the delivery catheter an into the aneurysm. 
     In still another embodiment of the present disclosure, an apparatus for treating an aneurysm in a blood vessel includes an occlusion element configured to be releasably coupled to an elongate delivery shaft, the occlusion element including a first tubular mesh having a first end, a second end, a wall and a lumen, the first end and the second end of the first tubular mesh coupled together at a proximal end of the occlusion element such that an intermediate portion of the first tubular mesh between the first end and the second end includes a substantially 180 degree turn, the intermediate portion of the first tubular mesh extending distally from the proximal end of the occlusion element, wherein the intermediate portion of the first tubular mesh has a collapsed configuration configured to be delivered through the inner lumen of the delivery catheter, and wherein the intermediate portion of the first tubular mesh is configured to expand to an expanded configuration when advanced out of the distal end of the inner lumen of the delivery catheter an into the aneurysm. In some embodiments, the apparatus further includes a second tubular mesh having a first end, a second end, a wall and a lumen, the first end and the second end of the second tubular mesh coupled to the proximal end of the occlusion element such that an intermediate portion of the second tubular mesh between the first end and the second end includes a substantially 180 degree turn, the intermediate portion of the second tubular mesh extending distally from the proximal end of the occlusion element, wherein the intermediate portion of the second tubular mesh has a collapsed configuration configured to be delivered through the inner lumen of the delivery catheter, and wherein the intermediate portion of the second tubular mesh is configured to expand to an expanded configuration when advanced out of the distal end of the inner lumen of the delivery catheter an into the aneurysm. 
     In another embodiment of the present disclosure, an apparatus for treating an aneurysm in a blood vessel includes an occlusion element configured to be releasably coupled to an elongate delivery shaft, the occlusion element including a mesh body configured to be delivered in a collapsed configuration through an inner lumen of a delivery catheter, the inner lumen having a proximal end and a distal end, the body further configured to expand to an expanded configuration when advanced out of the distal end of the inner lumen of the delivery catheter and into the aneurysm, wherein the body includes a proximal portion having a proximal maximum transverse dimension A and a distal maximum transverse dimension B and a frustoconical portion extending between the proximal maximum transverse dimension A and the distal maximum transverse dimension B, and wherein the body further includes distal portion having a maximum transverse dimension C and a waist portion between the proximal portion and the distal portion, and wherein the dimension A is between about 50% and about 100% of dimension B. 
     In another embodiment of the present disclosure, an apparatus for treating an aneurysm in a blood vessel includes an occlusion element configured to be releasably coupled to an elongate delivery shaft, the occlusion element including an inverted mesh tube having an outer layer and an inner layer, the outer layer transitioning to the inner layer at an inversion fold, wherein at least the outer layer is formed into an expanded shape having a proximal section having a first diameter, a distal section having a second diameter, and a waist portion having a third diameter, wherein the third diameter is less than the first diameter and the third diameter is less than the second diameter. 
     In yet another embodiment of the present disclosure, an apparatus for treating an aneurysm in a blood vessel includes an occlusion element configured to be releasably coupled to an elongate delivery shaft, the occlusion element including an inverted mesh tube having an outer layer and an inner layer, the outer layer transitioning to the inner layer at an inversion fold, wherein at least the outer layer is formed into an expanded shape having a proximal section having a first diameter, a distal section having a second diameter, and a first waist portion having a third diameter, a middle section having a fourth diameter, and a second waist portion having a fifth diameter, wherein the first diameter, the second diameter, and the fourth diameter are each greater than the third diameter, and wherein the first diameter, the second diameter, and the fourth diameter are each greater than the fifth diameter. 
     In still another embodiment of the present disclosure, a method for forming an apparatus for treating an aneurysm in a blood vessel includes forming a mesh tube, inverting the mesh tube to form an outer layer and an inner layer, the outer layer transitioning to the inner layer at an inversion fold, forming at least the outer layer into an expanded shape having a proximal section having a first diameter and a distal section having a second diameter, and etching the distal section to decrease its stiffness. 
     In yet another embodiment of the present disclosure, an apparatus for treating an aneurysm in a blood vessel includes an occlusion element configured to be releasably coupled to an elongate delivery shaft, the occlusion element including an inverted mesh tube having an outer layer and an inner layer, the outer layer transitioning to the inner layer at an inversion fold, the occlusion element configured to be delivered in a collapsed configuration through an inner lumen of a delivery catheter, the inner lumen having a proximal end and a distal end, the occlusion element further configured to expand to an expanded configuration when advanced out of the distal end of the inner lumen of the delivery catheter and into the aneurysm, wherein in the expanded configuration, at least the outer layer of the inverted mesh tube is formed into an expanded shape including a proximal section having a first transverse dimension, a distal section having a second transverse dimension, and a waist portion having a third transverse dimension, wherein the third transverse dimension is less than the first transverse dimension, and the third transverse dimension is less than the second transverse dimension, and wherein in the expanded configuration, the waist portion is configured to be deformed by an externally applied force such that a distance between the distal section and the proximal section is decreased. 
     In another embodiment of the present disclosure, a vaso-occlusive system configured for embolizing an aneurysm, the aneurysm having a neck and a sac, the system including an elongate pusher configured to be slidably disposed within a delivery catheter, the delivery catheter having a proximal end, a distal end, and a delivery lumen extending therebetween, an implantable vaso-occlusive device coupled to a distal end of the pusher, the vaso-occlusive device configured for implantation in the aneurysm sac and having a collapsed delivery configuration when restrained within the delivery lumen of the delivery catheter, and an expanded, deployed configuration after being delivered out of the delivery lumen of the delivery catheter and into the aneurysm sac, wherein the vaso-occlusive device includes a proximal face configured to seat against a lower wall portion of the sac of the aneurysm against the neck of the aneurysm and a concavity, opposite the proximal face, and having a perimeter extending into the sac and away from the neck of the aneurysm, the concavity arranged around a longitudinal axis, and wherein the vaso-occlusive device is configured to be releasably coupled to the distal end of the pusher at a releasable joint, the distal end of the pusher extending from the releasable joint at an angle formed with the central longitudinal axis of between about 30 degrees and about 120 degrees. 
     In another embodiment of the present disclosure, a vaso-occlusive system configured for embolizing an aneurysm, the aneurysm having a neck and a sac, the system including an elongate pusher configured to be slidably disposed within a delivery catheter, the delivery catheter having a proximal end, a distal end, and a delivery lumen extending therebetween, an implantable vaso-occlusive device coupled to a distal end of the pusher, the vaso-occlusive device configured for implantation in the aneurysm sac and having a collapsed delivery configuration when restrained within the delivery lumen of the delivery catheter, and an expanded, deployed configuration after being delivered out of the delivery lumen of the delivery catheter and into the aneurysm sac, wherein the vaso-occlusive device includes a proximal face configured to seat against a lower wall portion of the sac of the aneurysm against the neck of the aneurysm and a concavity, opposite the proximal face, and having a perimeter extending into the sac and away from the neck of the aneurysm, the concavity arranged around a longitudinal axis, and wherein the vaso-occlusive device is configured to be releasably coupled to the distal end of the pusher at a releasable joint, and wherein the releasable joint is coupled at a location on the proximal face of the vaso-occlusive device that is radially offset from the central longitudinal axis. 
     In yet another embodiment of the present disclosure, a vaso-occlusive system configured for embolizing an aneurysm, the aneurysm having a neck and a sac, the system including an elongate pusher configured to be slidably disposed within a delivery catheter, the delivery catheter having a proximal end, a distal end, and a delivery lumen extending therebetween, an implantable vaso-occlusive device coupled to a distal end of the pusher, the vaso-occlusive device configured for implantation in the aneurysm sac and having a collapsed delivery configuration when restrained within the delivery lumen of the delivery catheter, and an expanded, deployed configuration after being delivered out of the delivery lumen of the delivery catheter and into the aneurysm sac, wherein the vaso-occlusive device includes a proximal face configured to seat against a lower wall portion of the sac of the aneurysm against the neck of the aneurysm and a concavity, opposite the proximal face, and having a perimeter extending into the sac and away from the neck of the aneurysm, the concavity arranged around a longitudinal axis, and wherein the vaso-occlusive device is configured to be releasably coupled to the distal end of the pusher at a releasable joint, and wherein the releasable joint has a characteristic chosen from the list consisting of: (1) the distal end of the pusher extends from the releasable joint at an angle formed with the central longitudinal axis of between about 30 degrees and about 120 degrees, and (2) the releasable joint is coupled at a location on the proximal face of the vaso-occlusive device that is radially offset from the central longitudinal axis. 
     In still another embodiment of the present disclosure, a system for embolizing an aneurysm includes an expandable implant configured for placement within an aneurysm, the implant having a collapsed configuration and an expanded configuration, the expanded configuration having an asymmetric shape in relation to a longitudinal axis, and a delivery catheter having a proximal end and a distal end and a lumen extending from the proximal end to the distal end, the lumen having a non-circular cross-section at least at a distal region adjacent the distal end of the delivery catheter, wherein expandable implant in its collapsed configuration is configured to fit into the lumen in the distal region in a keyed manner, such that the expandable implant is deliverable from the lumen at the distal end of the delivery catheter in a particular rotational position in relation to the longitudinal axis. 
     In yet another embodiment of the present disclosure, a method for inserting an expandable implant includes providing an introducer having a proximal end and a distal end and an introducer lumen extending between the proximal end of the introducer and the distal end of the introducer, the introducer lumen configured to hold an expandable implant in its collapsed configuration while the expandable implant is introduced into the lumen of the delivery catheter at its proximal end, wherein the lumen of the delivery catheter has a non-circular shape, and wherein the expandable implant in its collapsed configuration has a substantially non-circular shape, pushing the expandable implant out of the introducer lumen and into the lumen of the delivery catheter such that the substantially non-circular shape of the expandable implant in its collapsed configuration is oriented in a keyed manner with the non-circular shape of the lumen of the delivery catheter, and advancing the expandable implant such that it is entirely within the lumen of the delivery catheter. 
     In still another embodiment of the present disclosure, a vaso-occlusive system configured for embolizing an aneurysm, the aneurysm having a neck and a sac, the system includes an elongate pusher configured to be slidably disposed within a delivery catheter, the delivery catheter having a proximal end, a distal end, and a delivery lumen extending therebetween, an implantable vaso-occlusive device coupled to a distal end of the pusher, the vaso-occlusive device configured for implantation in the aneurysm sac and having a collapsed delivery configuration when restrained within the delivery lumen of the delivery catheter, and an expanded, deployed configuration after being delivered out of the delivery lumen of the delivery catheter and into the aneurysm sac, wherein the vaso-occlusive device includes a proximal end configured to seat against the aneurysm adjacent the neck of the aneurysm, a distal end configured to extend in the sac and away from the neck of the aneurysm, and a central longitudinal axis, and wherein the vaso-occlusive device is configured to be releasably coupled to the distal end of the pusher at a releasable joint, wherein the releasable joint includes either one or both of the configurations in the list consisting of: (1) the distal end of the pusher extends from the releasable joint at an angle formed with the central longitudinal axis of between about 30 degrees and about 120 degrees, and (2) the releasable joint is coupled at a location on the proximal end of the vaso-occlusive device that is radially offset from the central longitudinal axis. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a sectional view of an occlusion device according to an embodiment of the present disclosure. 
         FIG. 2  is a perspective view of an occlusion device according to an embodiment of the present disclosure. 
         FIG. 3  is a perspective view of the occlusion device of  FIG. 2 . 
         FIG. 4  is a perspective view of the occlusion device of  FIG. 2 . 
         FIG. 5  is a perspective view of the occlusion device of  FIG. 1 . 
         FIG. 6  is a partial sectional view of the occlusion device of  FIG. 2  delivered into a terminal aneurysm. 
         FIG. 7  illustrates an occlusion device delivered into a terminal aneurysm, according to an embodiment of the present disclosure. 
         FIG. 8  is a perspective view of an occlusion device according to an embodiment of the present disclosure. 
         FIG. 9  is a perspective view of an occlusion device according to an embodiment of the present disclosure. 
         FIG. 10A  is a perspective view of an occlusion device according to an embodiment of the present disclosure. 
         FIG. 10B  is a detail view of an alternative distal end of the occlusion device of  FIG. 10A , according to an embodiment of the present disclosure. 
         FIG. 10C  is a detail view of an alternative distal end of the occlusion device of  FIG. 10A , according to an embodiment of the present disclosure. 
         FIG. 10D  is a detail view of an alternative distal end of the occlusion device of  FIG. 10A , according to an embodiment of the present disclosure. 
         FIG. 10E  is a detail view of an alternative distal end of the occlusion device of  FIG. 10A , according to an embodiment of the present disclosure. 
         FIG. 11A  is a side view of the occlusion device of  FIG. 10A . 
         FIG. 11B  is a detail view of the detachment portion of the occlusion device of  FIG. 10A , prior to detachment. 
         FIG. 11C  is a detail view of the detachment portion of the occlusion device of  FIG. 10A , during detachment. 
         FIG. 12  is a perspective view of an occlusion device according to an embodiment of the present disclosure. 
         FIG. 13  is a perspective view of the occlusion device of  FIG. 12  delivered into an aneurysm. 
         FIG. 14  is a perspective view of an occlusion device delivered into an aneurysm, according to an embodiment of the present disclosure. 
         FIG. 15  is a perspective view of the occlusion device of  FIG. 14 . 
         FIG. 16  is a perspective view of an occlusion device according to an embodiment of the present disclosure. 
         FIG. 17  is a perspective view of an occlusion device according to an embodiment of the present disclosure. 
         FIG. 18  is a perspective view of an occlusion device according to an embodiment of the present disclosure. 
         FIG. 19  is a sectional view of the occlusion device of  FIG. 18  within a delivery catheter. 
         FIG. 20  is a cross-sectional view of the occlusion device of  FIG. 18  taken through line  20 - 20 . 
         FIG. 21  is a cross-sectional view of an alternative embodiment of the present disclosure. 
         FIG. 22  is a cross-sectional view of the of the occlusion device of  FIG. 18  taken through line  22 - 22 . 
         FIGS. 23-26  illustrate the implantation of the occlusion device of  FIG. 18  in an aneurysm of a blood vessel of a patient. 
         FIG. 27  is a perspective view of an occlusion device according to an alternative embodiment of the present disclosure. 
         FIG. 28  is a sectional view of the occlusion device of  FIG. 27  within a delivery catheter. 
         FIG. 29  is a cross-sectional view of the of the occlusion device of  FIG. 27  taken through line  29 - 29 . 
         FIG. 30  is a cross-sectional view of the of the occlusion device of  FIG. 27  taken through line  30 - 20 . 
         FIGS. 31-32  illustrate the implantation of the occlusion device of  FIG. 27  in an aneurysm of a blood vessel of a patient. 
         FIG. 33  is a perspective view of an occlusion device according to an alternative embodiment of the present disclosure. 
         FIG. 34  is a perspective view of an occlusion device according to an alternative embodiment of the present disclosure. 
         FIG. 35  is a perspective view of an occlusion device according to an alternative embodiment of the present disclosure. 
         FIG. 36  is a perspective view of an occlusion device according to an alternative embodiment of the present disclosure. 
         FIG. 37  is a perspective view of an occlusion device according to an alternative embodiment of the present disclosure. 
         FIG. 38  is a longitudinal sectional view of an occlusion device according to an alternative embodiment of the present disclosure. 
         FIG. 39  is a view of an occlusion device implanted within an aneurysm according to an embodiment of the present disclosure. 
         FIG. 40  is a view of an occlusion device implanted within an aneurysm according to an embodiment of the present disclosure. 
         FIG. 41  is a perspective view of an occlusion device according to an embodiment of the present disclosure. 
         FIG. 42  is a sectional view of the occlusion device of  FIG. 41 . 
         FIG. 43  is a sectional view of an alternative occlusion device, according to an embodiment of the present disclosure. 
         FIG. 44  is a sectional view of an alternative occlusion device, according to an embodiment of the present disclosure. 
         FIG. 45  is a sectional view of an alternative occlusion device, according to an embodiment of the present disclosure. 
         FIGS. 46-49  illustrate the implantation of the occlusion device of  FIG. 41  in an aneurysm of a blood vessel of a patient. 
         FIG. 50  is a sectional view of an alternative occlusion device, according to an embodiment of the present disclosure. 
         FIG. 51  is a sectional view of an alternative occlusion device, according to an embodiment of the present disclosure. 
         FIG. 52  is a sectional view of an alternative occlusion device, according to an embodiment of the present disclosure. 
         FIG. 53  is a sectional view of an alternative occlusion device, according to an embodiment of the present disclosure. 
         FIG. 54  is an occlusion device according to an embodiment of the present disclosure implanted within an aneurysm. 
         FIG. 55  is an occlusion device according to an embodiment of the present disclosure implanted within an aneurysm. 
         FIG. 56  illustrates an occlusion device according to an embodiment of the present disclosure implanted within an aneurysm. 
         FIG. 57  illustrates an occlusion device according to an embodiment of the present disclosure implanted within an aneurysm 
         FIG. 58  illustrates an occlusion device according to an embodiment of the present disclosure. 
         FIG. 59  is a sectional view of an unrestrained occlusion device according to an embodiment of the present disclosure. 
         FIG. 60  is the occlusion device of  FIG. 59  restrained within a delivery catheter. 
         FIG. 61  is the occlusion device of  FIG. 59  delivered restrained within an aneurysm. 
         FIG. 62  is a sectional view of an occlusion device according to an embodiment of the present disclosure. 
         FIG. 63  is a side view of an occlusion device according to an embodiment of the present disclosure. 
         FIG. 64  is a plan view of an occlusion device according to an embodiment of the present disclosure. 
         FIG. 65  is a plan view of the occlusion device of  FIG. 64  releasably coupled to a pusher, according to an embodiment of the present disclosure. 
         FIG. 66  is a perspective view of the occlusion device of  FIG. 64  implanted within a simulated aneurysm, according to an embodiment of the present disclosure. 
         FIG. 67  is a perspective view of the occlusion device of  FIG. 64  implanted within a simulated aneurysm, according to an embodiment of the present disclosure. 
         FIG. 68  is a sectional view of an alternative occlusion device, according to an embodiment of the present disclosure. 
         FIG. 69  is a perspective view of an occlusion device according to an embodiment of the present disclosure. 
         FIG. 70  is a sectional view of the occlusion device according to an embodiment of the present disclosure. 
         FIG. 71  is a sectional view of the occlusion device of  FIG. 70  being delivered within a microcatheter. 
         FIG. 72  is a sectional view of the occlusion device of  FIG. 70  being deployed from a microcatheter. 
         FIG. 73  is a detail sectional view of a distal end of the occlusion device of  FIG. 70 . 
         FIGS. 74A-74C  are sectional views of the delivery of an occlusion device of an occlusion system into an aneurysm according to an embodiment of the present disclosure. 
         FIGS. 75A-75C  are sectional views of the delivery of an occlusion device of an occlusion system into an aneurysm according to an embodiment of the present disclosure. 
         FIGS. 76A-76C  are sectional views of the delivery of an occlusion device of an occlusion system into an aneurysm according to an embodiment of the present disclosure. 
         FIG. 77  is a plan view of an occlusion device according to an embodiment of the present disclosure. 
         FIG. 78  is a plan view of an occlusion device according to an embodiment of the present disclosure. 
         FIG. 79  is a perspective view of the delivery of an occlusion device of an occlusion system into an aneurysm according to an embodiment of the present disclosure. 
         FIG. 80  is a perspective view of the delivery of an occlusion device of an occlusion system into an aneurysm according to an embodiment of the present disclosure. 
         FIG. 81  is a perspective view of the delivery of an occlusion device of an occlusion system into an aneurysm according to an embodiment of the present disclosure. 
         FIG. 82  is a perspective view of the delivery of an occlusion device of an occlusion system into an aneurysm according to an embodiment of the present disclosure. 
         FIG. 83  is a perspective view of the delivery of an occlusion device of an occlusion system into an aneurysm according to an embodiment of the present disclosure. 
         FIG. 84  is a perspective view of the delivery of an occlusion device of an occlusion system into an aneurysm according to an embodiment of the present disclosure. 
         FIG. 85  is a top view of a delivery catheter according to an embodiment of the present disclosure. 
         FIG. 86  is a side view of the delivery catheter of  FIG. 85 . 
         FIG. 87  is a magnified cross-section view taken along line  87  of  FIG. 86 . 
         FIG. 88  is a top view of a delivery catheter according to an embodiment of the present disclosure. 
         FIG. 89  is a side view of the delivery catheter of  FIG. 88 . 
         FIG. 90  is a magnified cross-section view taken along line  90  of  FIG. 89 . 
         FIG. 91  is a perspective view of a loading sheath according to an embodiment of the present disclosure. 
         FIG. 92  is a perspective view of the loading sheath of  FIG. 91  with an occlusion device restrained in its collapsed configuration. 
         FIG. 93  is a perspective view of the loading sheath of  FIG. 91  being changed to another configuration. 
         FIG. 94  is a perspective of the loading sheath of  FIG. 91  being used to load an occlusion device into a proximal end of a delivery catheter. 
         FIGS. 95A-95E  are alternate configurations of the lumen of a delivery catheter, according to embodiments of the present disclosure. 
         FIG. 96A  is a perspective view of an occlusion device according to an embodiment of the present disclosure. 
         FIG. 96B  is a detail view of an alternative distal end of the occlusion device of  FIG. 96A , according to an embodiment of the present disclosure. 
         FIG. 96C  is a detail view of an alternative distal end of the occlusion device of  FIG. 96A , according to an embodiment of the present disclosure. 
         FIG. 96D  is a detail view of an alternative distal end of the occlusion device of  FIG. 96A , according to an embodiment of the present disclosure. 
         FIG. 96E  is a detail view of an alternative distal end of the occlusion device of  FIG. 96A , according to an embodiment of the present disclosure. 
         FIG. 97A  is a side view of the occlusion device of  FIG. 96A . 
         FIG. 97B  is a detail view of the detachment portion of the occlusion device of  FIG. 96A , prior to detachment. 
         FIG. 97C  is a detail view of the detachment portion of the occlusion device of  FIG. 96A , during detachment. 
     
    
    
     DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS 
     Aneurysms are abnormal bulging or weakening of a blood vessel, often an artery, and can have many complications. A bulging of the blood vessel can disrupt or put pressure on surrounding tissues. Cerebral aneurysms can result in a variety of side effects, such as impaired vision, impaired speech, impaired balance, etc. Further, the aneurysm creates a volume that is not along the main flow path of the blood through the blood vessel. It therefore can serve as a location for blood to become stagnant and, due to swirling eddy currents, can contribute to the formation of a thromboembolism. If an aneurysm ruptures, it can cause severe internal bleeding, which in cerebral arteries can often become fatal. 
     Aneurysms can be treated externally with open surgery. Such procedures typically involve closing off the entrance or “neck” of the aneurysm with a device such as vascular clip, clamp or a ligature. However, such open surgical procedures can be highly invasive and may lead to trauma to the adjacent tissue and other side effects. 
     Aneurysms can also be treated through endovascular procedures. In one procedure, detachable lengths of wires (e.g., coils) are inserted into the interior volume of the aneurysm using a catheter. The coils are intended to fill the volume of the aneurysm to decrease the flow of blood into the aneurysm, inducing stagnation of flow and stimulate clotting within the aneurysm. In settings of large cerebral aneurysms, filling of the aneurysm with multiple coils can lead to mass effect that may induce brain swelling and be an independent cause for new symptoms. In another procedure, for aneurysms with a relatively large neck, the adjunctive use of stents assists with the retention of the coils within the aneurysm. This approach may have a contraindication to being used when treating ruptured aneurysm, due to the need for additional anti-thrombotic medications. In another procedure, the coils are held in the volume of the aneurysm with a temporary balloon that is inflated in the blood vessel. The balloon is deflated and removed once the mass of coils is secured. In still another procedure, a stent device is placed in the artery to promote flow of blood past the aneurysm. This leads to stagnation of the blood within the aneurysm and thrombosis inside the aneurysm volume. However, a side branch of a main artery in which the stent device is placed may become trapped or “jailed,” which can impede access to the side branch. In other instances, the side branch can become clotted off, possibly causing a stroke. Additionally, such a procedure generally requires the use additional anti-thrombotic medications, which limits the use of such devices in the setting of treatment of ruptured aneurysms. The stent device is often formed with a relatively tight weave. While the tight weave increases the effectiveness of the stent device in diverting the blood flow, it also impedes or prevents access to the volume of the aneurysm or the jailed artery. In the event that the aneurysm fails to clot, the obstruction of the aneurysm by the stent device prevents the possibility of placing embolic devices inside the aneurysm. Additional procedures such as the placement of additional stents or open surgery may then be required to treat the residual. 
     Procedures that involve packing the volume of the aneurysm can suffer from several common shortcomings. First, it can take many coils of wire to fill the volume of the aneurysm, which is time consuming and increases the time it takes to complete the procedure. Further, the coils may be compacted over time to occupy a smaller percentage of the total volume of the aneurysm. A great enough compaction of the coils can be considered a recurrence of the aneurysm and may require further treatment. 
       FIGS. 1 and 5  illustrate an occlusion device  420  having a dual layer mesh, and comprising a single D-shaped element  422  having a D-shaped longitudinal section. the occlusion device  420  is constructed from an inverted mesh tube  424  having a first end  426 , a second end  428 , and a wall  429 . The inverted mesh tube  424  extends on an outer layer  430  from the second end  428  past a proximal end  432  of the D-shaped element  422  and along a hemisphere shape  434  to a maximum diameter portion  436  having an acute angulation  438 . From the maximum diameter portion  436 , the outer layer  430  extends radially inward along a substantially flattened portion  440  substantially overlaying a transverse plane, to an inversion fold  442  from the outer layer  430  to an inner layer  444  which follows the contours of the outer layer  430  from a distal orifice  446  to the first end  426 . The occlusion device  420  is fabricated as an inverted mesh tube  424  having a simple straight elongate configuration, and is subsequently formed into the shape shown in  FIGS. 1 and 5 , and heat set into this shape. For example, the inverted mesh tube  424  may be constructed as a single layer mesh tube formed of at least some nickel-titanium alloy filaments, and then inverted on itself. The inverted mesh tube  424  may then be placed into a die or mold comprising one or more pieces, to hold it in the shape of the D-shaped element  422 . Then, the D-shaped element  422  may be subjected to an elevated temperature and then cooled, to lock in the shape, resulting in a D-shaped element  422  having at least some superelastic properties. The occlusion device  420 , like all of the occlusion devices described herein, is configured to be delivered in a compressed configuration through the lumen of a delivery catheter and out of the distal end of the lumen into an aneurysm. When the occlusion device  420  is released from the constraints of the lumen, it self-expands to an expanded configuration within the aneurysm. A marker band  448  holds the first end  426  and the second end  428  together, and can comprise a radiopaque material such as platinum or a platinum alloy such as 90% platinum and 10% iridium, or 80% platinum and 20% iridium, or 75% platinum and 25% iridium. The D-shaped element  422  is configured to cover a neck portion of an aneurysm. The maximum diameter portion  436  can be configured to engage a wall portion of the aneurysm to maintain the occlusion device  420  in place. For example, the diameter of the maximum diameter portion  436  can be oversized in relation to the target aneurysm diameter, e.g., 10% greater, 20% greater, etc. In some embodiments, the occlusion device  420  in its expanded configuration has a general cross-sectional isosceles trapezoidal shape in a plane containing the longitudinal axis. In some embodiments, the occlusion device  420  in its expanded configuration has a general cross-sectional triangular shape in a plane containing the longitudinal axis. 
     The distal orifice  446  can be sized to control the overall width of the substantially flattened portion  440 . The smaller the distal orifice  446 , the thicker the width (on each side of the orifice  446 ) in the substantially flattened portion  440 . The thicker the width of this portion, the more radial force (aneurysm gripping force) can be placed on the aneurysm wall by the maximum diameter portion  436 . In some embodiments, the inner diameter of the orifice  446  is between about 35% to about 85% the diameter of the maximum outer diameter portion  463 . In some embodiments, the inner diameter of the orifice  446  is between about 45% to about 75% the diameter of the maximum outer diameter portion  463 . In some embodiments, the inner diameter of the orifice  446  is between about 50% to about 70% the diameter of the maximum outer diameter portion  463 . In some embodiments, the inner diameter of the orifice  446  is between about 55% to about 65% the diameter of the maximum outer diameter portion  463 . In some embodiments, the orifice  446  is on the same plane as the maximum outer diameter portion  463 . In other embodiments, the orifice  446  is on a plane that is distal to a plane generally carrying the maximum outer diameter portion  463 . In other embodiments, the orifice  446  is on a plane that is proximal to a plane generally carrying the maximum outer diameter portion  463 . 
       FIGS. 2-4  illustrate a bowl-shaped occlusion device  801  constructed from an inverted mesh tube  803  and having a concavity  805  at its distal end  807 . A laser-cut tapering coil  809  may be constructed from nickel-titanium sheet material or nickel titanium tubing. The inverted mesh tube  803  is not shown in  FIGS. 2-4  in order to show the detail of the coil  809 . The inverted mesh tube  803  is shown covering the coil  809  in  FIG. 6 , with the occlusion device  801  deployed in a terminal aneurysm  471 . In some embodiments, the coil  809  is between an outer layer  461  and an inner layer  463  of the inverted mesh tube  803 , and applies an outward radial force on the outer layer  461  and thereby on the aneurysm  471 . In other embodiments, the coil  809  is within both the outer layer  461  and the inner layer  463  of the inverted mesh tube  803  and applies an outward radial force on the inner layer  463  and outer layer  461  together, and on thereby on the aneurysm  471 . The coil  809  has a small diameter end  811  and a large diameter end  813 , tapering or varying in diameter between the two ends  811 ,  813 , thus to match the bowl-shape of the occlusion device  801 . In some embodiments, the coil  809  at least partially forces the bowl shape into the outer layer  461 , or into the inner layer  463  and outer layer  461 . In some embodiments, the coil  809  may even be outside of both the inner layer  463  and the outer layer  461 , and may be coupled to one or both of the inner layer  463  or outer layer  461  by adhesive bonding, epoxy bonding, hot melt, tying, sewing, weaving, welding, soldering, stapling, brazing, or other manners. Thus, the outward radial force applied by the coil  809  pulls the outer layer  461  and or the inner layer  463  outwardly. The maximum diameter of the occlusion device  801  (e.g., at the large diameter end  813 ) can be configured to engage a wall portion  491  of the aneurysm  471  to maintain the occlusion device  801  in place. For example, the maximum diameter can be oversized in relation to the target aneurysm diameter, e.g., 10% greater, 20% greater, etc. In some embodiments, the occlusion device  801  in its expanded configuration has a general cross-sectional isosceles trapezoidal shape in a plane containing the longitudinal axis. In some embodiments, the occlusion device  801  in its expanded configuration has a general cross-sectional triangular shape in a plane containing the longitudinal axis. 
     The occlusion device  801  is coupled to a pusher wire  481  and is delivered through a microcatheter  485  that is placed through the main artery  495 . After being deployed in the desired position, the occlusion device  801  is released from the pusher wire  481  by detachment at a detachable joint  489 . A detachable joint  489  may comprise one of a number of detachment systems, including but not limited to pressurized detachment, electrolytic detachment mechanisms, hydraulic detachment mechanisms, mechanical or interlocking detachment mechanisms, chemical detachment mechanisms, heat-activated detachment systems, or frictional detachment systems. During delivery, the pusher wire  481  is held on its proximal end (not shown) by a user and pushed in a forward longitudinal direction, in order to advance the occlusion device  801  to the distal end  493  of the delivery catheter (microcatheter)  485 . 
       FIG. 7  illustrates an occlusion device  815  deployed within an aneurysm and having several wire forms  817  (three shown) that loop back and attach to a proximal end  819  of the occlusion device  815  at each of their ends (first end  475 , second end  477 ). The loop portions  479  of the wire forms  817  are configured to grip within the aneurysm  829  by interfacing with the aneurysm wall  483 . A proximal mesh  821  includes a circumferentially-extending concave portion  823  that is configured to divert or steer blood flow toward side arteries  825 ,  827  as shown in curved arrows. The occlusion device  815  is shown in  FIG. 7  within a terminal aneurysm  829  (e.g., basilar tip or other terminal aneurysm,). The occlusion device  815  is delivered through a microcatheter  485  that is placed through the basilar artery  487 , and after being deployed in the desired position, is released from the pusher wire  481  by detachment at a detachable joint  489 . A detachable joint  489  may comprise one of a number of detachment systems, including but not limited to pressurized detachment, electrolytic detachment mechanisms, hydraulic detachment mechanisms, mechanical or interlocking detachment mechanisms, chemical detachment mechanisms, heat-activated detachment systems, or frictional detachment systems. During delivery, the pusher wire  481  is held on its proximal end (not shown) by a user and pushed in a forward longitudinal direction, in order to advance the occlusion device  815  to the distal end  493  of the delivery catheter (microcatheter)  485 . 
       FIG. 8  is a perspective view of a basket-shaped occlusion device  831 , having the general structure of the occlusion device  815  of  FIG. 7 , but having rounded wire forms  833  configured to conform to a dome of an aneurysm, and also to force the proximal mesh portion  835  against the neck portion of the aneurysm. 
       FIG. 9  illustrates an occlusion device  550  having a dual layer mesh, and comprising a disk-shaped element  552  having a disk-shaped longitudinal section. the occlusion device  550  is constructed from an inverted mesh tube  554  having a first end  556  and a second end  558 , and a wall  560 . The inverted mesh tube  554  extends on an outer layer  562  from the second end  558  past a proximal end  564  of the disk-shaped element  552  and along a hemisphere shape  566  to a maximum diameter portion  568 . From the maximum diameter portion  568 , the outer layer  562  extends radially inward and distally along a frustoconical portion  570  and along and adjacent radiused portion  572 , to an inversion fold  574  from the outer layer  562  to an inner layer  576  which follows the contours of the outer layer  562  from a distal orifice  578  to the first end  556 . The occlusion device  550  is fabricated as an inverted mesh tube  554  having a simple straight elongate configuration, and is subsequently formed into the shape shown in  FIG. 9 , and heat set into this shape. For example, the inverted mesh tube  554  may be constructed as a single layer mesh tube formed of at least some nickel-titanium alloy filaments, and then inverted on itself. The inverted mesh tube  554  may then be placed into a die or mold comprising one or more pieces, to hold it in the shape of the disk-shaped element  552 . Then, the disk-shaped element  552  may be subjected to an elevated temperature and then cooled, to lock in the shape, resulting in a disk-shaped element  552  having at least some superelastic properties. An internal marker band  580  is attached at its proximal end  582  to the first end  556  and the second end  558 , and can comprise a radiopaque material such as platinum or a platinum alloy such as 90% platinum and 10% iridium, or 80% platinum and 20% iridium, or 75% platinum and 25% iridium. The internal marker band  580  has a distal end  584  and a hollow lumen  586 . A pusher wire  588  is inserted through the lumen  586  of the internal marker band  580  and has a distal end  590  having radially-extending protrusions  592 . The disk-shaped element  552  is configured to cover a neck portion of an aneurysm. The maximum diameter portion  568  can be configured to engage a wall portion of the aneurysm to maintain the occlusion device  550  in place. For example, the diameter of the maximum diameter portion  568  can be oversized in relation to the target aneurysm diameter, e.g., 10% greater, 20% greater, etc. 
       FIGS. 10A and 11A-11C  illustrate an occlusion device  1040  comprising a mesh cover  1042  including a distal concavity  1044 . An internal tube  1046  having a lumen  1048  and an outer wall  1050  is secured within the mesh cover  1042 , such that its proximal end  1052  is flush or closely adjacent to a proximal end  1054  of the mesh cover  1042 . A pusher  1056  comprises a wire having a distal end  1058  including a plurality of radially-extending fingers  1060  which extend from the distal end  1058 . The fingers  1060  are configured to be meltable, detachable, unbendable, breakable, ablatable, deformable, or otherwise changeable. Prior to detachment, the radially-extending fingers  1060  create a maximum diameter that is larger than the diameter of the lumen  1048  of the internal tube  1046 , such that traction on the wire of the pusher  1056  causes the fingers  1060  to pull on the distal end of the outer wall  1050  of the internal tube  1046 , and thus the pull the entire occlusion device  1040 . For example, the occlusion device  1040  may be advanced into an aneurysm, and if the user does not believe the fit or configuration of the occlusion device  1040  within the aneurysm is desirable, the user may pull on the pusher  1056  to pull the occlusion device  1040  out of the aneurysm and into the lumen of the delivery catheter. However, then the occlusion device  1040  has been delivered into the aneurysm in an acceptable manner, the user may detach by any detachment manner (to deform, damage, or destroy the fingers  1060 ), via modes including but not limited to pressurized detachment, electrolytic detachment mechanisms, hydraulic detachment mechanisms, mechanical or interlocking detachment mechanisms, chemical detachment mechanisms, heat-activated detachment systems, or frictional detachment systems. In one embodiment, mechanical detachment is achieved by pushing the distal end of the microcatheter against the proximal end  1054  of the mesh cover  1042  while pulling on the pusher  1056 , thus bending the fingers  1060 , and removing the pusher  1056  from the occlusion device  1040 . The internal tube  1046  provides for a smooth proximal end  1054  of the mesh cover  1042 , and thus no remnant wire protruding proximally. Remnant protruding wires could cause thrombosis, which may cause embolic stroke. In some embodiments, the distal end  1058  of the pusher  1056  may taper down to as small as 0.001 inch or 0.002 inch, for example, if the distal end  1058  comprises a stainless steel wire. The internal tube  1046  may comprise a polyimide tube, and may have an internal diameter as small as 0.002 inch to 0.010 inch and an outer diameter of between about 0.003 inch and about 0.014 inch. In some embodiments there may be two fingers  1060 , or three fingers  1060 , or four fingers  1060 , or five fingers  1060 , of six fingers,  1060 , or more. 
     The flush or adjacent relation of the proximal end  1052  of the internal tube  1046  to a proximal end  1054  of the mesh cover  1042  assures that there is no detachment remnant extending substantially proximal to the proximal end  1054  of the mesh cover  1042  (and into the parent artery). Thus, any potentially related thromboembolic events may be avoided, in cases wherein such a remnant would be a risk. In some embodiments, the minimum outer diameter of the mesh cover  1042  is between about 70% and about 90% of the maximum outer diameter of the mesh cover  1042 .  FIG. 10B  illustrates an alternative distal end  1058   b  comprising a ball  1062  having a spherical or globular shape. The detachment may occur at the ball  1062 , or at a portion  1064  of the distal end  1058   b  proximal to the ball  1062 , or at both. The ball  1064  may be attached to the pusher  1056  by epoxy, adhesive, welding, brazing, or soldering, or may be formed from the material of distal end  1058   b  by welding.  FIG. 10C  illustrates an alternative distal end  1058   c  comprising a disk  1066  having a flattened, circular shape. The detachment may occur at the disk  1066 , or at a portion  1068  of the distal end  1058   c  proximal to the disk  1066 , or at both. The disk  1066  may be attached to the pusher  1056  by epoxy, adhesive, welding, brazing, or soldering, or may be formed from the material of distal end  1058   c  by welding.  FIG. 10D  illustrates an alternative distal end  1058   d  comprising a tip  1070  having a frustoconical shape. The detachment may occur at the tip  1070 , or at a portion  1072  of the distal end  1058   d  proximal to the tip  1070 , or at both. The tip  1070  may be attached to the pusher  1056  by epoxy, adhesive, welding, brazing, or soldering, or may be formed from the material of distal end  1058   d  by welding.  FIG. 10E  illustrates an alternative distal end  1058   e  comprising a tip  1076  having a flattened reverse spear shape. The detachment may occur at the tip  1076 , or at a portion  1078  of the distal end  1058   e  proximal to the tip  1076 , or at both. The tip  1076  may be attached to the pusher  1056  by epoxy, adhesive, welding, brazing, or soldering, or may be formed from the material of distal end  1058   e  by welding, or may be a flattened portion of the pusher  1056  wire, e.g., by rolling or pressing. In each of the alternative embodiments, the diameter (or maximum transverse dimension) of the ball  1062 , the disk  1066 , the proximal end  1074  of the tip  1070 , or the distal end  1080  of the tip  1076  are greater than the diameter of the lumen  1048  of the internal tube  1046 , thus allowing the occlusion device  1040  to be detachably locked to the pushed  1056 . 
       FIG. 12  illustrates an occlusion device  600  having a dual layer mesh, and comprising a single bowl-shaped element  602  having a trapezoid-shaped longitudinal section. the occlusion device  600  is constructed from an inverted mesh tube  604  having a first end and a second end (not shown), both inserted (in a collapsed state) and bonded within a marker band  606 . The inverted mesh tube  604  extends on an outer layer  608  from the second end of the inverted mesh tube  604  past a proximal end  610  of the bowl-shaped element  602  and along a first substantially flattened portion  612  substantially overlaying a transverse plane, to a maximum diameter portion  614  having an acute angulation  616 . From the maximum diameter portion  614 , the outer layer  608  extends distally and radially inward along a frustoconical portion  618 , to an obtuse angulation  620 , to a second substantially flattened portion  622 , to an inversion fold  624  from the outer layer  608  to an inner layer  626  which follows the contours of the outer layer  608  from a distal orifice  628  to the first end of the inverted mesh tube  604 . The occlusion device  600  is fabricated as an inverted mesh tube  604  having a simple straight elongate configuration, and is subsequently formed into the shape shown in  FIG. 12 , and heat set into this shape. For example, the inverted mesh tube  604  may be constructed as a single layer mesh tube formed of at least some nickel-titanium alloy filaments, and then inverted on itself. The inverted mesh tube  604  may then be placed into a die or mold comprising one or more pieces, to hold it in the shape of the bowl-shaped element  602 . Then, the bowl-shaped element  602  may be subjected to an elevated temperature and then cooled, to lock in the shape, resulting in a bowl-shaped element  602  having at least some superelastic properties. The marker band  606  holds the first end and the second end of the inverted mesh tube  604  together, and can comprise a radiopaque material such as platinum or a platinum alloy such as 90% platinum and 10% iridium, or 80% platinum and 20% iridium, or 75% platinum and 25% iridium. 
     The bowl-shaped element  602  is configured to cover a neck portion of an aneurysm. The maximum diameter portion  614  can be configured to engage a wall portion of the aneurysm to maintain the occlusion device  600  in place. For example, the diameter of the maximum diameter portion  614  can be oversized in relation to the target aneurysm diameter, e.g., 10% greater, 20% greater, etc. As shown in  FIG. 13 , the maximum diameter portion  614  engages with an aneurysm  630  at a proximal portion  632  just distal to the neck  634  of the aneurysm  630 . Because the maximum diameter portion  614  is oversized in relation to the diameter of the proximal portion  632  of the aneurysm  630 , and because the maximum diameter portion  614  is at a proximal portion of the bowl-shaped element  602 , the second substantially flattened portion  622  and/or the frustoconical portion  618  are able to deform as needed such that the bowl-shaped element  602  adjusts its shape to the shape of the aneurysm  630 . The occlusion device  600  is detachably coupled to a pusher wire  636  it a detachable joint  638 . In some embodiments, the minimum outer diameter of the bowl-shaped element  602  is between about 70% and about 90% of the maximum outer diameter of the bowl-shaped element  602 . 
       FIGS. 14-15  illustrate an occlusion device  837  constructed from an inverted mesh tube  839  and having a proximal end  715  and a concavity  841  at its distal end  845 .  FIG. 14  illustrates the occlusion device  837  implanted within an aneurysm  847  having a neck  710  and a dome  712  with a microcatheter  714  and a pusher  716 , as taught previously herein. The inverted mesh tube  839  includes a support stent  718  secured between an outer layer  720  and an inner layer  722  of the inverted mesh tube  839 . The stent  718  is configured to apply supplemental radial force against the wall  724  of the aneurysm  847 , to increase the grip of the occlusion device  837  within the aneurysm  847 , adjacent the neck  710 . The stent  718  allows for a larger radial force, and a better snug fit, than an inverted mech tube  839  with no stent. The stent  718  may comprise a nickel-titanium alloy, and may be laser machined from nickel-titanium alloy tubing. The tubing may be machined by other techniques that allow slot patterns to be formed in the wall. The stent  718 , after machining, may be heat formed to create an expanded diameter with superelastic characteristics. Though a “zig zag” shape  726  is shown in  FIGS. 14-15 , alternatively, the stent  718  may comprise modular sections, with open cell or closed cell designs. In some embodiments, the stent  718  may comprise a braided ring. In other embodiments, the stent may comprise a wire coil. In alternative embodiments, the stent is secured within both the outer layer  720  and the inner layer  722 , and serve to force both of these layers toward a larger diameter. In some embodiments, the stent  718  may even be secured outside both the outer layer  720  and the inner layer  722 , and function to “pull” both of these layers toward an increased outer diameter. The stent  718  may be secured to either of both of the outer layer  720  and the inner layer  722  by tying, waving, braiding, soldering, welding, brazing, adhesive, epoxy, or other types of bonding or attachment. In some embodiments, the stent is captured within the outer layer  720  and the inner layer  722  without being directly secured to any of the mesh or either layer. 
       FIG. 16  illustrates an occlusion device  730  comprising a single or dual layer mesh cover  732  and having a radiopaque wire ring  734  having a first end  736  and a second end  738 , both secured at the proximal end  740  of the occlusion device  730 . The radiopaque wire ring  734  loops to an intermediate portion  742  at a distal end  744  of the occlusion device  730 . The mesh cover  732  may comprise nickel-titanium alloy, and/or DFT, and/or platinum filaments/wires. The mesh cover  732  need not comprise DFT, platinum, or other radiopaque materials, because the radiopaque wire ring  734  comprises a radiopaque material and, because of its shape, represents the general size and shape of the occlusion device  730 . In some embodiments, the radiopaque wire ring  734  comprises a platinum flat wire, giving it sufficient mass to be clearly visible on fluoroscopy or x-ray, but a low profile when folded down in the minor dimension, when the occlusion device is collapsed for placement through the lumen of a microcatheter. In other embodiments, the radiopaque wire ring  734  may comprise a woven rope of radiopaque strands having a flat shape. 
       FIG. 17  illustrates an alternative version of an occlusion device  849 , similar to the occlusion device  730 , but having a first radiopaque wire ring  851  and a second radiopaque wire ring  853 . As shown in  FIG. 17 , the two radiopaque wire rings  851 ,  853  may be generally orthogonal to each other. The two radiopaque wire rings  851 ,  853  secure to the single or dual layer mesh cover  855  in a similar manner to that if the occlusion device  730  of  FIG. 16 . The two the radiopaque wire rings  851 ,  853  are configured to represents the general size and shape of the occlusion device  849  in multiple axes, for example, if bi-plane fluoroscopy is not being used, or to add additional precision in bi-plane fluoroscopy. The occlusion devices  730 ,  849  of  FIGS. 16 and 17  may also be constructed with some of all of their filaments in the mesh cover  732 ,  855  comprising DFT wires. A proximal marker band (not shown) may also be added to increase radiopacity. 
     In some embodiments, braided elements may be subsequently etched (chemical etch, photochemical etch) to decrease the overall wire diameter and decrease the stiffness. 
       FIG. 18  illustrates an occlusion device  100  configured for placement within an aneurysm. The occlusion device  100  comprises a cover  102  having an outer diameter D. In some embodiments, the cover  102  is circular, with substantially the same diameter D at any transverse measurement around the perimeter. In other embodiments, the cover  102  is non-circular, and may comprise an ellipse, an oval, a polygon or other shapes. In the non-circular embodiments, the cover  102  comprises a minimum transverse dimension and a maximum transverse dimension. In the particular case of an ellipse or an oval shape, the cover  102  comprises a major diameter and a minor diameter. The minor diameter or minimum transverse dimension is configured to be larger than a maximum transverse dimension of an opening into the aneurysm (the neck portion). Thus, the cover  102  is configured to completely cover the neck portion, and thus to cause stagnation of blood within the aneurysm, leading to occlusion. The cover  102  is constructed from a mesh (braided) Nitinol (nickel-titanium alloy) tube  105  that is inverted on itself. The mesh tube  105  has a first end  104  and a second end  106  (see  FIG. 20 ). The second end  106  is folded back over the outer diameter of the first end  104  thus providing an outer facing surface  108  and an inner facing surface  110 . The mesh tube  105  is heat-formed such that cover  102  comprises an expanded portion and the first end  104  and second end  106  comprise unexpanded (or partially expanded) portions. A smooth fold  112  extends around the circumference  114  of the cover  102  and represents the transition between the outer facing surface  108  and the inner facing surface  110 . The fold  112  avoids any sharp edge that might risk rupture of an aneurysm wall, or other anatomical damage. The cover  102  includes a concavity  116  facing toward the distal end  118  of the occlusion device  100  and away from the proximal end  120  of the occlusion device  100 . The cover  102  is fabricated as an inverted mesh tube  105  having a simple straight elongate configuration, and is subsequently formed into the shape shown in  FIG. 18 , and heat set into this shape. For example, the inverted mesh tube  105  may be constructed as a single layer mesh tube formed of at least some nickel-titanium alloy filaments, and then inverted on itself. The inverted mesh tube  105  may then be placed into a die or mold comprising one or more pieces, to hold it in the shape of the cover  102 . Then, the cover  102  may be subjected to an elevated temperature and then cooled, to lock in the shape, resulting in a cover  102  having at least some superelastic properties. The cover  102  includes a lower portion  107  opposite the fold  112 . The lower portion  170  is substantially flat, generally defining a plane, but in other embodiments may have a more frustoconical or hemispheric shape. 
     As formed (e.g., heat-formed), the cover  102  has an expanded configuration (shown in  FIG. 18 ) and a collapsed configuration, shown in  FIG. 19 . The cover  102  comprises two mesh layers, provided by the outer facing surface  108  and the inner facing surface  110 . In some embodiments, the cover  102  may comprise some nickel-titanium alloy filaments and some radiopaque elements, comprising platinum, gold, tantalum, or alloys of any of these or other radiopaque materials. In some embodiments, the filaments may comprise drawn filled tubes (DFT), such as those comprising a nickel-titanium alloy outer wall and a platinum core. The radiopaque material allows the cover  102  to be visible on radiographs or fluoroscopy. The occlusion device  100  may be configured by controlling how much radiopaque material is used, by either the ratio of radiopaque filaments to non-radiopaque filaments, or by the amount of platinum core in the drawn filled tubes. In this manner, the cover  102  can be selectively fabricated to be sufficiently visible, but not over visible, e.g., overly bright, such that other objects are obscured. In some embodiments, whether any of the filaments comprise radiopaque materials or not, a marker band may be attached to the proximal end  120  of the occlusion device  100 , by adhesive or epoxy bonding, or swaging, welding or other mechanical attachment. 
     Extending from the concavity  116  is a doubled-over or looped tubular mesh  122  having a smooth apex  124  configured to safely contact an interior wall of an aneurysm. The tubular mesh  122  has a first end  126  and a second end  128 , and an intermediate portion  130  extending between the first end  126  and second end  128 . In the embodiment shown in  FIG. 18 , the first end  126  and second end  128  are substantially unexpanded and are inserted within a lumen  132  within the inverted mesh tube  105  that forms the cover  102 , particularly at the first end  104  and a second end  106  of the mesh tube  105  that forms the cover  102  ( FIG. 20 ). The first end  126  and second end  128  of the tubular mesh  122  can be bonded into the lumen  132  with adhesive  134 , or alternatively with epoxy, or welded or bonded with any other securement technique. The first end  126  and second end  128  may each be compressed or deformed into an oval, elliptical, or D-shape, so that they may more efficiently fit into a circular cross-section of the lumen  132 . An alternative configuration is shown in  FIG. 21 , wherein the first end  126  includes a cut  142  in its wall  144 , which allows the second end  128  to be inserted into the internal space  146  at the first end  126 . Thus, the second end  128  is held within the first end  126 , and the first end  126  and second end  128  are secured within the lumen  132 , e.g., with adhesive, epoxy, welding or other securing techniques. The tubular mesh  122  is constructed from a mesh (braided) Nitinol (nickel-titanium alloy) tube, and may also include filaments of platinum or other radiopaque materials, as well as the nickel-titanium filaments. Drawn filled tubes may also be utilized. 
     Between the apex  124  of the intermediate portion  130  and the first and second ends  126 ,  128 , the tubular mesh  122  intermediate portion  130  also comprises a first leg  136  and a second leg  138 , extending therefrom. Each of the first leg  136  and second leg  138  comprises a different section of the tubular mesh  122 . Thus, the tubular mesh  122  is a single layer mesh (braided) tube extending from its first end  126  through the first leg  136  and around the apex  124 , then through the second leg  138  to the second end  128 . In the embodiment shown in  FIG. 18 , the first leg  136  and second leg  138  are shown in their substantially unrestrained, expanded states, and, in this embodiment, the first leg  136  and second leg  138  each have a large enough diameter such that they contact each other at a central axis  140 . Turning to  FIG. 22 , it can be appreciated that the first leg  136  and second leg  138  each form a more oval or elliptical cross-sectional shape, rather than a circular shape, because of their opposition to each other at the central axis  140 . Also, the first leg  136  and second leg  138  together form a first transverse dimension TD X  and a second transverse dimension TD Y . In this embodiment, the first transverse dimension TD X  is greater than the second transverse dimension TD Y . In other embodiments, the first transverse dimension TD X  is less than the second transverse dimension TD Y . In some embodiments, the first transverse dimension TD X  is equal to the second transverse dimension TD Y . In some cases, the first transverse dimension TD X  is configured to contact an interior wall of an aneurysm, to stabilize the occlusion device  100  within the aneurysm, while the second transverse dimension TD Y  is not. In some cases, the second transverse dimension TD Y  is configured to contact an interior wall of an aneurysm, to stabilize the occlusion device  100  within the aneurysm, while the first transverse dimension TD X  is not. In some cases, the occlusion device  100  may be placed into a non-circular aneurysm, and in these cases, the first transverse dimension TD X  and the second transverse dimension TD Y  may each be configured to contact an interior wall of an aneurysm at different circumferential locations, as the aneurysmal cross-section may be more oval or elliptical, or another non-circular shape. 
     Returning to  FIG. 19 , the occlusion device  100  is shown with both the cover  102  and the tubular mesh  122  in their collapsed or compacted configurations while it is placed into the lumen  148  of a delivery catheter  150  having a distal end  162  and a proximal end  164 . The delivery catheter  150  may be a microcatheter having a luminal diameter of 0.017 inch or 0.021 inch, 0.025 inch, or 0.028 inch, or other sizes. An elongate pusher  152 , having a distal end  154  and a proximal end  156 , may comprise a wire, a hypo tube, or another elongate structure having column support, and is detachably coupled at its distal end  154  to the proximal end  120  of the occlusion device  100 . A detachable joint  158  may comprise one of a number of detachment systems, including but not limited to pressurized detachment, electrolytic detachment mechanisms, hydraulic detachment mechanisms, mechanical or interlocking detachment mechanisms, chemical detachment mechanisms, heat-activated detachment systems, or frictional detachment systems. During delivery, the pusher  152  is held on its proximal end  156  by a user and pushed in a forward longitudinal direction  160 , in order to advance the occlusion device  100  to the distal end  162  of the delivery catheter  150 . 
     In  FIGS. 23-26 , an aneurysm  10  having a neck portion  16  is shown. The occlusion device  100  is shown in use being implanted by a user (e.g., physician) into the aneurysm  10  through the delivery catheter  150  to disrupt or halt the flow of blood flow between the blood vessel  12  and the internal volume  14  of the aneurysm  10 , thereby reducing the likelihood that the aneurysm  10  will rupture. Or, in cases in which the aneurysm  10  has already ruptured, the occlusion device  100  is being implanted to help heal the rupture and/or to prevent rerupture. The occlusion device  100  is configured to be low profile device, minimizing disruptions to surrounding bodies, such as a side branch  18  of the blood vessel  12 . The blood vessel  12  has a blood vessel wall  13  and the aneurysm  10  has an aneurysm wall  11 . In  FIG. 23 , the delivery catheter  150  is advanced through a sheath and/or guiding catheter (not shown) through a puncture or cutdown in a peripheral blood vessel, such as a femoral artery, a brachial artery, or a radial artery. The distal end  162  of the delivery catheter  150  may be shaped with a curve, as shown, either by the manufacturer, or prior to the procedure by the user, in order to allow for improved backup support when delivering the occlusion device  100 , as well as to aid deliverability into the aneurysm  10 . The distal end  162  of the delivery catheter  150  is placed adjacent the neck portion  16  of the aneurysm  10 . The delivery catheter  150  may first be advanced over a guidewire (not shown) that is passed through the lumen  148 . The guidewire may then be removed, leaving the lumen  148  as a delivery conduit and the delivery catheter  150  as a support column. 
     In  FIG. 24 , the occlusion device  100  is advanced through the lumen  148  of the delivery catheter  150 , as described, and the distal end  118  of the occlusion device  100 , having a smooth apex  124  (of a curve in the tubular mesh  122 ) is advanced out of the lumen  148  and into the internal volume  14  of the aneurysm  10 . The smooth apex  124  is the first portion of the occlusion device  100  that exits the lumen  148  and thus is the first portion of the occlusion device to enter the aneurysm  10 . The smooth apex  124 , because of is curved and contoured surface as well as its flexible mesh wall, is a blunt, soft, and atraumatic element that is configured to first contact the interior surface  15  of the aneurysm  10 . The smooth apex  124  can contact the interior surface  15  and slide around the interior surface  15  is a less traumatic manner than most devices that are configured to implant into an aneurysm, such as small diameter detachable coils. The atraumatic characteristics of the smooth apex  124  make it fully deployable not only in unruptured cerebral aneurysms, but also in ruptured cerebral aneurysms, where certain other devices may be contraindicated. In  FIG. 25 , the occlusion device  100  is shown in a substantially expanded configuration within the internal volume  14  of the aneurysm  10 . The cover  102  is expanded against the interior surface  15  of the aneurysm  10 , and covers the neck portion  16  of the aneurysm. The tubular mesh  122  is expanded against the interior surface  15  of the aneurysm  10 , at least at one or more portions, and serves to anchor or stabilize the cover  102  in the aneurysm  10  and adjacent the neck portion  16 . 
     Also, in  FIG. 25 , the detachable joint  158  has been detached, and thus, the free end  154  of the pusher  152  can be pulled into the lumen  148  of the delivery catheter  150 . In some embodiments, the delivery catheter  150  is maintained over the detachable joint  158  during the detachment procedure, to further protect the aneurysm  10 . In  FIG. 26 , the delivery catheter  150  is removed, and the deployed occlusion device  100  is in place to begin to occlude the internal volume  14  of the aneurysm  10 . The expanded tubular mesh  122  also serves to force the cover  102  against the neck portion  16  and/or against the interior surface  15 , see straight arrow in  FIG. 26 . The dual layers of mesh in the cover  102  at the lower portion  107  ( FIGS. 18 and 26 ) aid in the disruption of blood flow into the aneurysm  10 , thus causing thrombosis to isolate the internal volume  14  of the aneurysm  10  from blood flow through the blood vessel.  12 . The force (straight arrow) maintaining the cover  102  in place further assures this process, and also protects against undesired compaction over time of the occlusion device  100 , whether it be compaction in the longitudinal direction or compaction in a transverse or radial direction. 
       FIG. 27  illustrates an occlusion device  500  configured for placement within an aneurysm. The occlusion device  500  is an alternative configuration of the occlusion device  100  of  FIG. 18 , comprises a cover  502  having an outer diameter DD. In some embodiments, the cover  502  is circular, with substantially the same diameter DD at any measurement around the perimeter at each transverse plane. In other embodiments, the cover  502  is non-circular, and may comprise a cross-section having an ellipse, an oval, a polygon or other shapes. In the non-circular embodiments, the cover  502  comprises a minimum transverse dimension and a maximum transverse dimension. In the particular case of an ellipse or an oval shape, the cover  502  comprises a major diameter and a minor diameter. The minor diameter or minimum transverse dimension is configured to be larger than a maximum transverse dimension of an opening into the aneurysm (the neck portion). Thus, the cover  502  is configured to completely cover the neck portion, and thus to cause stagnation of blood within the aneurysm, leading to occlusion. The cover  502  is constructed from a mesh (braided) Nitinol (nickel-titanium alloy) tube  505  that is inverted on itself. The mesh tube  505  has a first end  504  and a second end  506  ( FIG. 28 ), similar to the first end  104  and second end  106  of  FIG. 20 . The second end  506  is folded back over the outer diameter of the first end  504  thus providing an outer facing surface  508  and an inner facing surface  510  ( FIG. 30 ). The mesh tube  505  is heat-formed such that cover  502  comprises an expanded portion and the first end  504  and second end  506  comprise unexpanded (or partially expanded) portions. The heat forming may be done as described in relation to the occlusion device  100  of  FIG. 18 . The cover  502  has a general disk shape defined by the outer facing surface  508 . In some embodiments, the cover  502  may comprise a toroidal, partially-toroidal shape. The occlusion device  500  includes a distal end  518  and a proximal end  520 . As formed (e.g., heat-formed), the cover  502  has an expanded configuration (shown in  FIG. 27 ) and a collapsed configuration, shown in  FIG. 28 . The cover  502  comprises two mesh layers, provided by the outer facing surface  508  and the inner facing surface  510 . In some embodiments, the cover  502  may comprise some nickel-titanium alloy filaments and some radiopaque elements, comprising platinum, gold, tantalum, or alloys of any of these or other radiopaque materials. In some embodiments, the filaments may comprise drawn filled tubes (DFT), such as those comprising a nickel-titanium alloy outer wall and a platinum core. The radiopaque material allows the cover  502  to be visible on radiographs or fluoroscopy. The occlusion device  500  may be configured by controlling how much radiopaque material is used, by either the ratio of radiopaque filaments to non-radiopaque filaments, or by the amount of platinum core in the drawn filled tubes. In this manner, the cover  502  can be selectively fabricated to be sufficiently visible, but not over visible, e.g., overly bright, such that other objects are obscured. In some embodiments, whether any of the filaments comprise radiopaque materials or not, a marker band  521  may be attached to the proximal end  520  of the occlusion device  500 , by adhesive or epoxy bonding, or swaging, welding or other mechanical attachment. 
     Extending from an opening  503  in a distal portion  519  the cover  502  is a first doubled-over or looped tubular mesh  522  and a second doubled-over or looped tubular mesh  523 . The first looped tubular mesh  522  has a smooth apex  524  configured to safely contact an interior wall of an aneurysm. The second looped tubular mesh  523  has an apex  525  configured to fit within a central axis  540  of the first tubular mesh  522 . The first tubular mesh  522  and the second tubular mesh  523  are oriented at non-parallel planes to one another. As shown in  FIG. 29 , in one embodiment, the first tubular mesh  522  and the second tubular mesh  523  are orthogonal to each other, and substantially follow orthogonal planes, or planes at right angles to one another. The first tubular mesh  522  has a first end  526  and a second end  528 , and an intermediate portion  530  extending between the first end  526  and second end  528 . In the embodiment shown in  FIG. 27 , the first end  526  and second end  528  are substantially unexpanded and are inserted within a lumen (not shown) within the inverted mesh tube  505  that forms the cover  502 , in a similar manner to the first end  104  and the second end  106  in  FIG. 20 . Similarly, the second tubular mesh  523  has a first end  527  and a second end  529 , and an intermediate portion  531  extending between the first end  527  and second end  529 . In the embodiment shown in  FIG. 27 , the first end  527  and second end  529  are substantially unexpanded and are inserted within a lumen (not shown) within the inverted mesh tube  505  that forms the cover  502 . The first ends  526 ,  527  and second ends  528 ,  529  of the first tubular meshes  522 ,  523  can be bonded into the lumen with adhesive, or alternatively with epoxy, or welded or bonded with any other securement technique. The first ends  526 ,  527  and second ends  528 ,  529  may each be compressed or deformed into an oval, elliptical, or D-shape, so that they may more efficiently fit into a circular cross-section of the lumen. The alternative configuration of  FIG. 21  may also be employed. The first tubular mesh  522  and second tubular mesh  523  may each be constructed from a mesh (braided) Nitinol (nickel-titanium alloy) tube, and may also include filaments of platinum or other radiopaque materials, as well as the nickel-titanium filaments. Drawn filled tubes may also be utilized. 
     Between the apex  524  of the intermediate portion  530  and the first and second ends  526 ,  528 , the tubular mesh  522  intermediate portion  530  also comprises a first leg  536  and a second leg  538 , extending therefrom. Between the apex  525  of the intermediate portion  531  and the first and second ends  527 ,  528 , the tubular mesh  523  intermediate portion  531  also comprises a first leg  537  and a second leg  539 , extending therefrom. In the embodiment shown in  FIG. 27 , the first legs  536 ,  537  and the second leg  538 ,  539  are shown in their expanded states. Turning to  FIG. 29 , the spacing between the first leg  536 , first leg  537 , second leg  538 , and second leg  539  can be appreciated. Each leg  536 ,  537 ,  538 ,  539  may form a circular cross-sectional shape when expanded, or may form a more oval or elliptical cross-sectional shape, because of their opposition to or interface with each other. Each leg pair  536 / 538 ,  537 / 539  may form a first transverse dimension TD X  and a second transverse dimension TD Y , respectively (see  FIG. 29 ). For example, in some embodiments, the first transverse dimension TD X  may be greater than the second transverse dimension TD Y . In some embodiments, the first transverse dimension TD X  may be less than the second transverse dimension TD Y . In some embodiments, the first transverse dimension TD X  is configured to contact an interior wall of an aneurysm, to stabilize the occlusion device  500  within the aneurysm, while the second transverse dimension TD Y  is not. In some embodiments, the second transverse dimension TD Y  is configured to contact an interior wall of the aneurysm, while the first transverse dimension TD X  is not. In some embodiments, both the first transverse dimension TD X  and the second transverse dimension TD Y  are configured to contact an interior wall of the aneurysm. The cover  502  may alternatively have a distal concavity, like the cover  102  of the occlusion device  100  of  FIG. 18 . Furthermore, the cover  102  of the occlusion device  100  of  FIG. 18  may utilize a cover  502  without a distal concavity, and instead with an opening  503 , as in the occlusion device  500  of  FIG. 27 . 
     Turning to  FIG. 28 , the occlusion device  500  is shown with both the cover  502  and the tubular meshes  522 ,  523  in their collapsed or compacted configurations while it is placed into the lumen  148  of a delivery catheter  150  having a distal end  162  and a proximal end  164 . The delivery catheter  150  may be a microcatheter having a luminal diameter of 0.017 inch or 0.021 inch, 0.025 inch, or 0.028 inch, or other sizes. An elongate pusher  857 , having a distal end  859  and a proximal end  861 , may comprise a wire, a hypo tube, or another elongate structure having column support, and is detachably coupled at its distal end  859  to the proximal end  520  of the occlusion device  500 . A detachable joint  863  may comprise one of a number of detachment systems, including but not limited to pressurized detachment, electrolytic detachment mechanisms, hydraulic detachment mechanisms, mechanical or interlocking detachment mechanisms, chemical detachment mechanisms, heat-activated detachment systems, or frictional detachment systems. During delivery, the pusher  857  is held on its proximal end  861  by a user and pushed in a forward longitudinal direction  160 , in order to advance the occlusion device  500  to the distal end  162  of the delivery catheter  150 . 
     In  FIG. 31 , the occlusion device  500  is shown in a substantially expanded configuration within the internal volume  14  (see  FIG. 23 ) of the aneurysm  10 . The cover  502  is expanded against the interior surface  15  of the aneurysm  10 , and covers the neck portion  16  of the aneurysm. One or both of the first tubular mesh  522  and the second tubular mesh  523  are expanded against the interior surface  15  (see  FIG. 23 ) of the aneurysm  10 , and serve(s) to anchor or stabilize the cover  502  in the aneurysm  10  and adjacent the neck portion  16 . Also, in  FIG. 31 , the detachable joint  863  has been detached, and thus, the free end  859  of the pusher  857  can be pulled into the lumen  148  of the delivery catheter  150 . In some embodiments, the delivery catheter  150  is maintained over the detachable joint  863  during the detachment procedure, to further protect the aneurysm  10 . In  FIG. 32 , the delivery catheter  150  is removed, and the deployed occlusion device  500  is in place to begin to occlude the internal volume  14  of the aneurysm  10 . The expanded first tubular mesh  522  and expanded second tubular mesh  523  also serve to force the cover  502  against the neck portion  16  and/or against the interior surface  15 , see straight arrow in  FIG. 32 . The dual layers of mesh in the cover  502  at a lower portion  507  aid in the disruption of blood flow into the aneurysm  10 , thus causing thrombosis to isolate the internal volume  14  of the aneurysm  10  from blood flow through the blood vessel.  12 . The force (straight arrow) maintaining the cover  502  in place further assures this process, and also protects against undesired compaction over time of the occlusion device  500 . 
       FIG. 33  illustrates an occlusion device  865  comprising a first doubled-over or looped tubular mesh  867  and a second doubled-over or looped tubular mesh  203 . The occlusion device  865  is similar to the occlusion device  500  of  FIG. 27 , however there is no cover (e.g., cover  502 ). The first tubular mesh  867  includes a first end  869  and a second end  871 , and the second tubular mesh has a first end  873  and a second end  875 . All four ends  869 ,  871 ,  873 ,  875  are held, in the collapsed or constrained configuration of the tubular mesh  867 ,  203 , within a cylindrical marker band  877 . The marker band  877  may comprise stainless steel or a radiopaque material such as platinum, and the ends  869 ,  871 ,  873 ,  875  may be bonded within a lumen of the marker band  877  with adhesive or epoxy, or may be brazed, soldered, or welded. The first looped tubular mesh  867  has an intermediate portion  211  having a smooth apex  879  configured to safely contact an interior wall of an aneurysm. The second looped tubular mesh  203  has an intermediate portion  213  having an apex  881  configured to fit within a central axis  883  of the first tubular mesh  867 . The first tubular mesh  867  and the second tubular mesh  203  are oriented at non-parallel planes to one another. A shown in  FIG. 33 , the first tubular mesh  867  and the second tubular mesh  203  are substantially orthogonal to each other, and substantially follow orthogonal planes, or planes at right angles to one another. Because there is no cover, a first proximal portion  885  and second proximal portion  887  of the first tubular mesh  867 , and a first proximal portion  889  and second proximal portion  891  of the second tubular mesh  203  are shaped and configured to serve (as did the cover  502 ) to be disposed against the proximal portion of an aneurysm, adjacent the neck of the aneurysm, to substantially provide occlusion of the neck. 
       FIG. 34  illustrates an occlusion device  893  comprising a doubled-over or looped tubular mesh  895  and a cover  897 . The cover  897  comprises a single layer mesh tube  900  that is heat shaped as described herein. The cover  897  comprises a proximal end  899  (bonded within a marker band  901 ) and a flared distal end  902  that is allowed to expand freely. The tubular mesh  895  comprises a first end  903  and a second end  904  that are also bonded within the marker band  901 , and an intermediate portion  905  having a smooth apex  906 . An inner surface  907  of a first leg  251  of the tubular mesh  895  may be configured to touch an inner surface  908  of a second leg  253  of the tubular mesh  895  when the tubular mesh  895  is in its expanded configuration. In other embodiments, the tubular mesh may be sized and configured such that the inner surfaces  907 ,  908  do not typically touch each other with the tubular mesh is in its expanded configuration. A proximal face  909  of the cover  897  is configured to be disposed against the proximal portion of an aneurysm, adjacent the neck of the aneurysm, to substantially provide occlusion of the neck. A maximum diameter portion  910  of the cover  897  may be configured to engage with a wall surface on the aneurysm. Additionally, a maximum transverse dimension portion  258  of the intermediate portion  905  of the mesh tube  895  is configured to engage a wall of the aneurysm. 
       FIG. 35  illustrates an occlusion device  300  comprising a cover  302  including a concavity  304  facing toward the distal end  306  of cover  302  and away from the proximal end  308  of the cover  302 . The cover  302  is fabricated as an inverted mesh tube  310  having a simple straight elongate configuration, and is subsequently formed into the shape shown in  FIG. 35 , and heat set into this shape, as described previously herein. A smooth fold  316  extends around the distal end  306  cover  302  and represents the transition between an outer facing surface  318  and an inner facing surface  320 . The occlusion device  300  is similar to the occlusion device  100  of  FIG. 18 , however an orifice  312  opening into the concavity  304  is smaller than the maximum diameter  314  of the cover  302 . The orifice  312  has a diameter between about 35% and about 85% of the maximum diameter  314 , or between about 45% and about 75%, or between about 50% and about 70%, or between about 55% and about 65%. Extending from the concavity  304  is a doubled-over or looped tubular mesh  322  having a smooth apex  324  configured to safely contact an interior wall of an aneurysm. The tubular mesh  322  has a first end  326  and a second end  328 , and an intermediate portion  330  extending between the first end  326  and second end  328 . The cover  302  and the tubular mesh  322  may have differing characteristics from each other in order to optimize the performance characteristics of each. In certain embodiments, the cover  302  may comprise between 36 and 144 filaments, each having a diameter between about 0.00075 to 0.001 inch. In a particular embodiment, the cover  302  may comprise 72 nickel-titanium filaments, each having a diameter of 0.00085 inch. 
     In certain embodiments, the tubular mesh  322  may comprise between 18 and 36 filaments, each having a diameter between about 0.00075 and 0.00125 inch. In the particular embodiment described in relation to the cover  302 , the tubular mesh is constructed from 24 nickel titanium filaments, each having a diameter of 0.00093 inch. The particular diameters of 0.00085 and 0.00093 inch can be achieved by making the filaments with this diameter, or may be achieved by etching filaments having a slightly larger diameter (e.g., 0.001 inch) until the desired diameters are reached. In the particular embodiment, the cover  302  has a maximum diameter  314  (in the expanded state) of between about 4 mm and about 8 mm, or between about 5 mm and about 7 mm, or about 6 mm. The tubular mesh  322  has a diameter (in the expanded state) of between about 2 mm and 3 mm, or about 2.5 mm. In some embodiments some or all of the filaments may comprise drawn filled tubes (DFT) having a radiopaque cross-sectional fill area ratio of between about 10% to about 70%, or between about 51% to about 70%. The fill material can be platinum, or gold, or tantalum, or an alloy of any of these. The particular embodiment described has excellent compression in to a small diameter for delivery through a small catheter lumen, and has safe characteristics when expanded and delivered into an aneurysm. 
       FIG. 36  illustrates an occlusion device  332  comprising a cover  334  similar to the cover  302  of the occlusion device  300  of  FIG. 35 . However, there are three doubled-over or looped tubular meshes  336 ,  338 ,  340 , each having a smooth apex  342 ,  344 ,  346 , respectively. The three doubled-over or looped tubular meshes  336 ,  338 ,  340  are arrayed next to each other like books on a bookshelf. Because the diameter of their intermediate portions  337 ,  339 ,  341 , in the expanded configuration, are greater than the diameter of their ends, the three doubled-over or looped tubular meshes  336 ,  338 ,  340  are fanned out. In some embodiments, the three doubled-over or looped tubular meshes  336 ,  338 ,  340  together form a fanned angle α that is between about 15° and about 90°, or between about 20° and about 75°, or between about 30° and about 60°. In alternative embodiments, the three doubled-over or looped tubular meshes  336 ,  338 ,  340  inhabit three substantially parallel planes that are not coplanar to each other, and are thus the three doubled-over or looped tubular meshes  336 ,  338 ,  340  are linearly arrayed in a transverse dimension to the longitudinal axis  348  of the cover  334 . 
       FIG. 37  illustrates an occlusion device  350  comprising a cover  352  having a concavity  351 , the cover  352  similar to the cover  302  of the occlusion device  300  of  FIG. 35 . However, there are three doubled-over or looped tubular meshes  354 ,  356 ,  358 , each having a smooth apex  360 ,  362 ,  364 , respectively. The three doubled-over or looped tubular meshes  354 ,  356 ,  358  are arrayed next to each other like ribs of an opened folding hand fan. In some embodiments, all three of the looped tubular meshes  354 ,  356 ,  358  together approximate a single plane. In other embodiments, the looped tubular meshes  354 ,  356 ,  358  each approximate a different plane, together approximating an open triptych. In some embodiments, looped tubular meshes  354 ,  356 ,  358  together form a fanned angle β, between the centerline  355  of the first outside tubular mesh  354  and the centerline  357  of the second outside tubular mesh  358 , that is between about 15° and about 120°, or between about 20° and about 90°, or between about 25° and about 75°, or between about 30° and about 60°. In some embodiments, looped tubular meshes  354 ,  356 ,  358  together form a fanned angle γ, between the general outer contour line  359  of the first outside tubular mesh  354  and the general outer contour line  361  of the second outside tubular mesh  358 , that is between about 20° and about 150°, or between about 30° and about 120°, or between about 30° and about 90°. The outer contour lines  359 ,  361  extend between the attachment  366  of the first and second ends of the tubular mesh and a maximal lateral extension point  368 ,  369 . a maximum transverse dimension T is formed by the three looped tubular meshes  354 ,  356 ,  358 , and is configured to contact the inner surface of an aneurysm at both sides, to stabilize the occlusion device  350  within the aneurysm. The cover  352  is configured to seal or occlude the aneurysm adjacent the neck, as in the other covers presented herein. 
       FIG. 38  illustrates an occlusion device  370  comprising an outer cover  372  and an inner cover  374 . The outer cover  372  includes a concavity  376  facing toward the distal end  378  of outer cover  372  and away from the proximal end  380  of the outer cover  372 . The inner cover  374  is disposed within the concavity  376  of the outer cover  372  and includes a concavity  386  facing toward the distal end  388  of inner cover  374  and away from the proximal end  390  of the outer cover  374 . The outer cover  372  has a distal flare  392 , and the inner cover  374  has a maximum diameter  394  and a reduced diameter distal orifice  396 . The covers  372 ,  374  are each fabricated as inverted mesh tubes  382 ,  384  having a simple straight elongate configuration, and subsequently formed into the shapes shown in  FIG. 38 , and heat set into these shapes, as described previously herein. Either of the covers  372 ,  374  may have the material or dimensional characteristic of any other of the covers described herein. An overlap dimension Do has an increased braid density, because it is substantially the braid densities (e.g., picks per inch) of the two covers  372 ,  374  combined. Thus, substantial stagnation of blood flow can be achieved at the neck of the aneurysm to thrombose and occlude the aneurysm. Extending from the concavity  386  is a doubled-over or looped tubular mesh  398  having a smooth apex  399  configured to safely contact an interior wall of an aneurysm. The tubular mesh  398  has a first end  397  and a second end  395 , and an intermediate portion  393  extending between the first end  397  and second end  395 . The outer cover  372 , the inner cover  374 , and the tubular mesh  398  may each have differing characteristics from each other in order to optimize the performance characteristics of each. In one embodiment, the inner cover  374  has a first braid density and the outer cover  372  has a second braid density that is greater than the first braid density. The tubular mesh  398  has a third braid density that is less than the first braid density. In some embodiments, the second braid density is between 110% and 200% of the first braid density. In some embodiments, the first braid density is between 110% and 200% of the third braid density. In certain embodiments, the outer cover  372  may comprise between 24 and 48 filaments, the inner cover  374  may comprise between 12 and 36 filaments, and the tubular mesh  398  may comprise between 6 and 24 filaments. Each filament may have a diameter between about 0.0006 to about 0.0015 inch, or between about 0.00075 to about 0.00125 inch. In a particular embodiment, the outer cover  372  may comprise 36 filaments, the inner cover  374  may comprise 24 filaments, and the tubular mesh  398  may comprise 12 filaments. The filaments may comprise nickel-titanium alloy, or DFT wires, or a combination thereof. The inner cover  374  additionally can serve to stabilize the tubular mesh  398 , such that its loop remains substantially upright. The outer cover  372 , at its distal flare  392  is configured to grip the inner wall of an aneurysm. As in all of the occlusion devices, a marker band  379  may be carried at an end of the occlusion device  370  and be configured to hold the ends  395 ,  397  and to be a radiopaque indicator of the proximal end of the occlusion device  370  on x-ray or fluoroscopy. 
     In any of the embodiments presented herein, the doubled-over or looped tubular mesh may be configured to engage a portion of the interior wall of the aneurysm, up to an including the majority of the wall of the entire aneurysm sac. In any of the embodiments presented herein that include a cover, the cover may be configured to engage with an interior wall of the aneurysm at or adjacent the neck of the aneurysm. The engagement may include a radial force. In some embodiments, the cover may be configured to cover the neck of the aneurysm without significantly engaging the aneurysm wall with a radial force. 
     Additional materials may be carried on a proximal portion of the cover, or any part of the occlusion device that is adjacent the neck of the aneurysm, in order to facilitate healing of the neck of the aneurysm.  FIG. 39  illustrates an occlusion device  301  comprising a cover  303  that is coupled to a doubled-over or looped tubular mesh  305  having a first leg  307  and a second leg  309 . The cover  303  includes a biological layer  311  configured to encourage growth. In some embodiments, the biological layer  311  may comprise antibodies, in order to accelerate the formation of an endothelial layer, for example, by attracting endothelial progenitor cells (EPCs). In some embodiments, the biological layer  311  may comprise a natural membrane or structure, such as a membrane, such as a membrane from an ear, or a cornea, or an ultra-thin piece of ligament, or even a piece of blood vessel wall. 
       FIG. 40  illustrates an occlusion device  313  comprising a cover  315  that is coupled to a doubled-over or looped tubular mesh  317  having a first leg  319  and a second leg  321 . The cover  315  includes a polymer layer  323  configured to act as a simulated arterial wall. In some embodiments, the polymer layer  323  may comprise polytetrafluoroethylene, such as expanded polytetrafluoroethylene (ePTFE), such as that used in grafts. 
     The following clauses include examples of apparatus of the disclosure. 
     Clause 1: In one example, an apparatus for treating an aneurysm in a blood vessel includes an occlusion element configured to be releasably coupled to an elongate delivery shaft, the occlusion element including a cover including a mesh material and configured to be delivered in a collapsed configuration through an inner lumen of a delivery catheter, the inner lumen having a proximal end and a distal end, the cover further configured to expand to an expanded configuration when advanced out of the distal end of the inner lumen of the delivery catheter and into the aneurysm, wherein the cover includes a diameter that is greater than the diameter or maximum transverse dimension of a neck portion of the aneurysm, and wherein the cover includes a distal concavity configured to face away from the neck portion of the aneurysm, and a first tubular mesh having a first end, a second end, a wall and a lumen, the first end and the second end of the first tubular mesh coupled to a central portion of the cover such that an intermediate portion of the first tubular mesh between the first end and the second end includes a substantially 180 degree turn, the intermediate portion of the first tubular mesh extending from the distal concavity of the cover, wherein the intermediate portion of the first tubular mesh has a collapsed configuration configured to be delivered through the inner lumen of the delivery catheter, and wherein the intermediate portion of the first tubular mesh is configured to expand to an expanded configuration when advanced out of the distal end of the inner lumen of the delivery catheter an into the aneurysm. 
     Clause 2: In some examples, the apparatus includes clause 1, wherein the occlusion element is configured such that the intermediate portion of the first tubular mesh is the first portion delivered out of the distal end of the inner lumen of the delivery catheter. 
     Clause 3: In some examples, the apparatus includes clause 2, wherein the intermediate portion of the first tubular mesh, when in its expanded configuration, includes a first leg and a second leg, the first leg configured to contact the second leg. 
     Clause 4: In some examples, the apparatus includes any one of clauses 1-3, wherein the cover is formed from a tube having a cover lumen, and wherein the first end and second end of the first tubular mesh are configured to be inserted into the cover lumen. 
     Clause 5: In some examples, the apparatus includes clause 4, wherein the first end and the second end of the first tubular mesh are configured to be secured next to each other in a collapsed state within the cover lumen. 
     Clause 6: In some examples, the apparatus includes clause 4, further including a cut in the wall of the first tubular mesh at the first end, wherein the second end, in a collapsed state is held within the first end, and wherein the first end and second end are secured within the cover lumen. 
     Clause 7: In some examples, the apparatus includes either one of clauses 5 or 6, wherein the first end and the second end of the first tubular mesh are secured within the cover lumen at a location proximal to the distal concavity of the cover. 
     Clause 8: In some examples, the apparatus includes clause 7, further including a pusher having a proximal end and a distal end, wherein the occlusion element is configured to be releasably coupled to the distal end of the pusher at a releasable joint. 
     Clause 9: In some examples, the apparatus includes clause 8, wherein the releasable joint is located within the cover lumen adjacent to the location proximal to the distal concavity of the cover. 
     Clause 10: In some examples, the apparatus includes any one of clauses 1-3, wherein the intermediate portion of the first tubular mesh, when in its expanded configuration, has a maximum transverse dimension that is greater than the diameter of the cover. 
     Clause 11: In some examples, the apparatus includes any one of clauses 1-10, wherein the cover is circular. 
     Clause 12: In some examples, the apparatus includes any one of clauses 1-10, wherein the cover is elliptical or oval, and wherein the cover has a minor diameter or minimum transverse dimension that is greater than the diameter or maximum transverse dimension of the neck portion of the aneurysm. 
     Clause 13: In some examples, the apparatus includes any one of clauses 1-12, wherein the cover includes two layers of mesh. 
     Clause 14: In some examples, the apparatus includes clause 13, wherein the cover is constructed from an inverted mesh tube. 
     Clause 15: In some examples, the apparatus includes any one of clauses 1-14, wherein the cover includes a nickel-titanium alloy. 
     Clause 16: In some examples, the apparatus includes any one of clauses 1-15, wherein the first tubular mesh includes a nickel-titanium alloy. 
     Clause 17: In some examples, the apparatus includes any one of clauses 1-16, wherein the occlusion element includes a radiopaque material. 
     Clause 18: In some examples, the apparatus includes any one of clauses 1-17, wherein the radiopaque material includes a marker band. 
     Clause 19: In some examples, the apparatus includes any one of clauses 1-18, wherein the marker band is coupled to the first end and second end of the first tubular mesh. 
     Clause 20: In some examples, the apparatus includes either one of clauses 18 or 19, wherein the marker band is coupled to the proximal end of the cover. 
     Clause 21: In some examples, the apparatus includes either one of clauses 1 or 2, wherein the occlusion element further includes a second tubular mesh having a first end, a second end, a wall and a lumen, the first end and the second end of the second tubular mesh coupled to a central portion of the cover such that an intermediate portion of the second tubular mesh between the first end and the second end includes a substantially 180 degree turn, the intermediate portion of the second tubular mesh extending from the distal concavity of the cover, wherein the intermediate portion of the second tubular mesh has a collapsed configuration configured to be delivered through the inner lumen of the delivery catheter, and wherein the intermediate portion of the second tubular mesh is configured to expand to an expanded configuration when advanced out of the distal end of the inner lumen of the delivery catheter an into the aneurysm. 
     Clause 22: In some examples, the apparatus includes clause 21, wherein the intermediate portion of the first tubular mesh, when in its expanded configuration, includes a first leg and a second leg, and wherein the second tubular mesh passes between the first leg and the second leg of the first tubular mesh. 
     Clause 23: In some examples, the apparatus includes clause 22, wherein the substantially 180 degree turn of the first tubular mesh generally defines a first plane and wherein the substantially 180 degree turn of the second tubular mesh generally defines a second plane, the second plane non-parallel to the first plane. 
     Clause 24: In some examples, the apparatus includes clause 23, wherein the second plane is generally perpendicular to the first plane. 
     Clause 25: In another example, an apparatus for treating an aneurysm in a blood vessel, includes an occlusion element configured to be releasably coupled to an elongate delivery shaft, the occlusion element including a cover including a mesh material and configured to be delivered in a collapsed configuration through an inner lumen of a delivery catheter, the inner lumen having a proximal end and a distal end, the cover further configured to expand to an expanded configuration when advanced out of the distal end of the inner lumen of the delivery catheter and into the aneurysm, wherein the cover includes a diameter that is greater than the diameter or maximum transverse dimension of a neck portion of the aneurysm, a first tubular mesh having a first end, a second end, a wall and a lumen, the first end and the second end of the first tubular mesh coupled to a central portion of the cover such that an intermediate portion of the first tubular mesh between the first end and the second end includes a substantially 180 degree turn, the intermediate portion of the first tubular mesh extending from the distal concavity of the cover, wherein the intermediate portion of the first tubular mesh has a collapsed configuration configured to be delivered through the inner lumen of the delivery catheter, and wherein the intermediate portion of the first tubular mesh is configured to expand to an expanded configuration when advanced out of the distal end of the inner lumen of the delivery catheter an into the aneurysm, and a second tubular mesh having a first end, a second end, a wall and a lumen, the first end and the second end of the second tubular mesh coupled to a central portion of the cover such that an intermediate portion of the second tubular mesh between the first end and the second end includes a substantially 180 degree turn, the intermediate portion of the second tubular mesh extending from the distal concavity of the cover, wherein the intermediate portion of the second tubular mesh has a collapsed configuration configured to be delivered through the inner lumen of the delivery catheter, and wherein the intermediate portion of the second tubular mesh is configured to expand to an expanded configuration when advanced out of the distal end of the inner lumen of the delivery catheter an into the aneurysm. 
     Clause 26: In some examples, the apparatus includes clause 25, wherein the intermediate portion of the first tubular mesh, when in its expanded configuration, includes a first leg and a second leg, wherein the second tubular mesh passes between the first leg and the second leg of the first tubular mesh. 
     Clause 27: In some examples, the apparatus includes clause 25, wherein the wall of the first tubular mesh has a first opening and a second opening, wherein the second tubular mesh passes into the first opening and out of the second opening. 
     Clause 28: In some examples, the apparatus includes any one of clauses 25-27, wherein the cover includes an aperture in the mesh material and wherein the first tubular mesh and the second tubular mesh pass through the aperture. 
     Clause 29: In another example, an apparatus for treating an aneurysm in a blood vessel, includes an occlusion element configured to be releasably coupled to an elongate delivery shaft, the occlusion element including a cover including a mesh material and configured to be delivered in a collapsed configuration through an inner lumen of a delivery catheter, the inner lumen having a proximal end and a distal end, the cover further configured to expand to an expanded configuration when advanced out of the distal end of the inner lumen of the delivery catheter and into the aneurysm, wherein the cover in its expanded configuration has a transverse dimension that is greater than a maximum transverse dimension of a neck portion of the aneurysm, and a first tubular mesh having a first end, a second end, a wall and a lumen, the first end and the second end of the first tubular mesh coupled to a central portion of the cover such that an intermediate portion of the first tubular mesh between the first end and the second end includes a substantially 180 degree turn, the intermediate portion of the first tubular mesh extending distally from the central portion of the cover, wherein the intermediate portion of the first tubular mesh has a collapsed configuration configured to be delivered through the inner lumen of the delivery catheter, and wherein the intermediate portion of the first tubular mesh is configured to expand to an expanded configuration when advanced out of the distal end of the inner lumen of the delivery catheter an into the aneurysm. 
     Clause 30. In some examples, the apparatus includes clause 29, wherein the occlusion element is configured such that the intermediate portion of the first tubular mesh is configured to begin to exit the distal end of the inner lumen of the delivery catheter before the cover. 
     Clause 31: In some examples, the apparatus includes clause 30, wherein the intermediate portion of the first tubular mesh, in its expanded configuration, includes a first leg and a second leg, the first leg configured to contact the second leg. 
     Clause 32: In some examples, the apparatus includes clause 29, wherein the cover is formed from a tube having a cover lumen, and wherein the first end and second end of the first tubular mesh are configured to be inserted into the cover lumen. 
     Clause 33: In some examples, the apparatus includes clause 32, wherein the first end and the second end of the first tubular mesh are configured to be secured next to each other in a collapsed state within the cover lumen. 
     Clause 34: In some examples, the apparatus includes clause 33, wherein the cover includes a distal concavity configured to face away from the neck portion of the aneurysm. 
     Clause 35: In some examples, the apparatus includes clause 34, wherein the first end and the second end of the first tubular mesh are secured within the cover lumen at a location proximal to the distal concavity of the cover. 
     Clause 36: In some examples, the apparatus includes clause 32, further including an at least partially longitudinally extending cut in the wall of the first tubular mesh at the first end, wherein the second end, in a collapsed state, is surrounded by the first end, and wherein the first end and second end are secured within the cover lumen. 
     Clause 37: In some examples, the apparatus includes clause 29, further including a pusher having a proximal end and a distal end, wherein the occlusion element is releasably coupled to the distal end of the pusher at a releasable joint. 
     Clause 38: In some examples, the apparatus includes clause 29, wherein the intermediate portion of the first tubular mesh, in its expanded configuration, has a maximum transverse dimension that is greater than a maximum transverse dimension of the cover. 
     Clause 39: In some examples, the apparatus includes clause 29, wherein the cover includes two layers of mesh. 
     Clause 40: In some examples, the apparatus includes clause 39, wherein the cover is constructed from an inverted mesh tube. 
     Clause 41: In some examples, the apparatus includes clause 29, wherein the occlusion element further includes a second tubular mesh having a first end, a second end, a wall and a lumen, the first end and the second end of the second tubular mesh coupled to a central portion of the cover such that an intermediate portion of the second tubular mesh between the first end and the second end includes a substantially 180 degree turn, the intermediate portion of the second tubular mesh extending from the central portion of the cover, wherein the intermediate portion of the second tubular mesh has a collapsed configuration configured to be delivered through the inner lumen of the delivery catheter, and wherein the intermediate portion of the second tubular mesh is configured to expand to an expanded configuration when advanced out of the distal end of the inner lumen of the delivery catheter an into the aneurysm. 
     Clause 42: In some examples, the apparatus includes clause 41, wherein the intermediate portion of the first tubular mesh, when in its expanded configuration, includes a first leg and a second leg, and wherein the second tubular mesh passes between the first leg and the second leg of the first tubular mesh. 
     Clause 43: In some examples, the apparatus includes clause 42, wherein the substantially 180 degree turn of the first tubular mesh generally defines a first plane and wherein the substantially 180 degree turn of the second tubular mesh generally defines a second plane, the second plane non-parallel to the first plane. 
     Clause 44: In some examples, the apparatus includes clause 43, wherein the second plane is generally perpendicular to the first plane. 
     Clause 45: In some examples, the apparatus includes clause 41, wherein the wall of the first tubular mesh has a first opening and a second opening, wherein the second tubular mesh passes into the first opening and out of the second opening. 
     Clause 46: In some examples, the apparatus includes clause 45, wherein the first opening includes a first cut in the wall of the first tubular mesh and wherein the second opening includes a second cut in the wall of the tubular mesh. 
     Clause 47: In some examples, the apparatus includes clause 41, wherein the intermediate portion of the first tubular mesh, in its expanded configuration, has a maximum transverse dimension and the intermediate portion of the second tubular mesh, in its expanded configuration has a maximum transverse dimension, the maximum transverse dimension of the intermediate portion of the first tubular member greater than the maximum transverse dimension of the intermediate portion of the second tubular member. 
     Clause 48: In some examples, the apparatus includes clause 47, wherein the maximum transverse dimension of the intermediate portion of the first tubular mesh and the maximum transverse dimension of the intermediate portion of the second tubular mesh are each different from a maximum transverse dimension of the cover. 
     Clause 49: In some examples, the apparatus includes clause 41, wherein the cover includes an aperture in the mesh material at a distal end of the cover, and wherein the intermediate portion of the first tubular mesh and the intermediate portion of the second tubular mesh pass through the aperture. 
     Clause 50: In some examples, the apparatus includes clause 41, wherein the intermediate portion of the first tubular mesh, when in its expanded configuration, includes a first leg and a second leg, and wherein the second tubular mesh, when in its expanded configuration, includes a first leg and a second leg, the first leg of the first tubular mesh adjacent to and on a first side of the first leg of the second tubular mesh, and the second leg of the first tubular mesh adjacent to and on the first side of the second leg of the second tubular mesh. 
     Clause 51: In some examples, the apparatus includes clause 29 wherein the cover includes an aperture in the mesh material and wherein the intermediate portion of the first tubular mesh passes through the aperture. 
     Clause 52: In some examples, the apparatus includes clause 29, wherein the cover has a circular outer shape. 
     Clause 53: In some examples, the apparatus includes clause 29, wherein the cover has a longitudinal section having a substantially trapezoidal shape. 
     Clause 54: In some examples, the apparatus includes clause 29, wherein at least the mesh of the cover includes drawn filled tubes having a radiopaque core and a nickel-titanium alloy. 
     Clause 55: In some examples, the apparatus includes clause 54, wherein the radiopaque core of each of at least some of the drawn filled tubes has a cross-sectional area that is between about 51% and about 70% of the total cross-sectional area of the each of at least some of the drawn filled tubes. 
     Clause 56: In some examples, the apparatus includes clause 29, wherein the mesh of the cover is woven from filaments, and wherein between about 50 percent and about 100 percent of the filaments include drawn filled tubes. 
     Clause 57: In another example, an apparatus for treating an aneurysm in a blood vessel, includes an occlusion element configured to be releasably coupled to an elongate delivery shaft, the occlusion element including a first tubular mesh having a first end, a second end, a wall and a lumen, the first end and the second end of the first tubular mesh coupled together at a proximal end of the occlusion element such that an intermediate portion of the first tubular mesh between the first end and the second end includes a substantially 180 degree turn, the intermediate portion of the first tubular mesh extending distally from the proximal end of the occlusion element, wherein the intermediate portion of the first tubular mesh has a collapsed configuration configured to be delivered through the inner lumen of the delivery catheter, and wherein the intermediate portion of the first tubular mesh is configured to expand to an expanded configuration when advanced out of the distal end of the inner lumen of the delivery catheter an into the aneurysm. 
     Clause 58: In some examples, the apparatus includes clause 57, wherein the occlusion element further includes a second tubular mesh having a first end, a second end, a wall and a lumen, the first end and the second end of the second tubular mesh coupled to the proximal end of the occlusion element such that an intermediate portion of the second tubular mesh between the first end and the second end includes a substantially 180 degree turn, the intermediate portion of the second tubular mesh extending distally from the proximal end of the occlusion element, wherein the intermediate portion of the second tubular mesh has a collapsed configuration configured to be delivered through the inner lumen of the delivery catheter, and wherein the intermediate portion of the second tubular mesh is configured to expand to an expanded configuration when advanced out of the distal end of the inner lumen of the delivery catheter an into the aneurysm. 
       FIG. 41  illustrates an occlusion device  200  configured for placement within an aneurysm. The occlusion device  200  comprises a proximal section  202  and a distal section  204 , each constructed of a single, continuous dual layer mesh. Turning to  FIG. 42 , the occlusion device  200  is constructed from an inverted mesh tube  206  having a first end  208 , a second end  210 , and a wall  209 . The inverted mesh tube  206  extends on an outer layer  212  from the second end  210  past a proximal end  214  of the proximal section  202  and along a proximal hemisphere shape  216  to a maximum diameter portion  218  having an acute angulation  219 . From the maximum diameter portion  218 , the outer layer  212  extends radially inward along a substantially flattened portion  220  to a central waist  222 . The outer layer  212  then extends radially outward along a substantially flattened portion  224  of the distal section  204  to a maximum diameter portion  226  having an acute angulation  227  to a distal hemisphere shape  228  to a distal end  230  of the occlusion device  200 . The hemisphere shape  228  is configured to contact at least a portion of an aneurysm dome. The maximum diameter portion  226  has a diameter that is about equal to the diameter of the maximum diameter portion  218 , but in other embodiments, they may differ. The occlusion device  200  is substantially cylindrically symmetric around a central axis Z. However, in alternative embodiments, there may be certain portions of asymmetry, such as one or more indented or extended feature at a particular location in a perimeter. At the distal end  230 , the wall  209  is inverted inwardly at an inversion fold  232 , which creates a distal orifice  234  and an internal volume  236 . The wall  209  transitions at the inversion fold  232  from the outer layer  212  to an inner layer  238  which follows the contours of the outer layer  212  from the distal orifice  234  to the first end  208 . The inner layer  238  follows a hemisphere shape  240 , a maximum diameter portion  242  having an acute angulation  244 , a substantially flattened portion  246  of the distal section  204 , a central waist  248 , a substantially flattened portion  250  of the proximal section  202 , a maximum diameter portion  252  having an acute angulation  254 , and a hemisphere shape  256 . The occlusion device  200  is fabricated as an inverted mesh tube  206  having a simple straight elongate configuration, and is subsequently formed into the shape shown in  FIGS. 41 and 42  and heat set into this shape. For example, the occlusion device  200  may be constructed as a single layer mesh tube formed of at least some nickel-titanium alloy filaments, and then inverted on itself. The inverted mesh tube  206  may then be placed into a die or mold comprising one or more pieces, to hold it in the shape of the occlusion device  200 . Then, the occlusion device  200  may be subjected to an elevated temperature and then cooled, to lock in the shape, resulting in an occlusion device  200  having at least some superelastic properties. Each of the proximal section  202  and distal section  204  are configured to be compressed or compacted within the lumen  148  of a delivery catheter  150  (e.g., microcatheter). 
     In some embodiments, one or both of the proximal section  202  or the distal section  204  may comprise some nickel-titanium alloy filaments and some radiopaque elements, comprising platinum, gold, tantalum, or alloys of any of these or other radiopaque materials. In some embodiments, the filaments may comprise drawn filled tubes, such as those comprising a nickel-titanium alloy outer wall and a platinum core. The radiopaque material allows the occlusion device  200  to be visible on radiographs or fluoroscopy. The occlusion device  200  may be configured by controlling how much radiopaque material is used, by either the ratio of radiopaque filaments to non-radiopaque filaments, or by the amount of platinum core in the drawn filled tubes. In this manner, the occlusion device  200  can be selectively fabricated to be sufficiently visible, but not over visible, e.g., overly bright, such that other objects are obscured. In some embodiments, whether any of the filaments comprise radiopaque materials or not, a marker band may be attached to the proximal end  214  of the proximal section  202 , by adhesive or epoxy bonding, or swaging, welding or other mechanical attachment. 
       FIG. 43  illustrates an occlusion device  260  also comprising an inverted mesh tube  262  and having an outer layer  264 , an inner layer  266 , and an inversion fold  268 , which creates a distal orifice  270 , and serves as the transition between the outer layer  264  and the inner layer  266 . The inverted mesh tube  262  has a first end  284  and a second end  286 . The occlusion device  260  includes a proximal section  272  and a distal section  274 . The proximal section  272  and distal section  274  have substantially flattened portions  276 ,  278 , and the distal section  274  has a distal hemisphere shape  280 , configured to contact an aneurysm dome. There is a waist  281  between the substantially flattened portions  276 ,  278 . The maximum diameter portion  279  has a diameter that is about equal to the diameter of the maximum diameter portion  277 , but in other embodiments, they may differ. The proximal section  272  includes a concave cone shape  282 , or circumferentially-extending concavity, which may be configured to direct blood flow, particularly when the occlusion device  260  is implanted within a bifurcation aneurysm or a terminal aneurysm, wherein the blood flow is directed along the paths of arrow  288  or arrow  290 . The occlusion device  260  may comprise any of the materials and be made with any of the processes described in relation to the occlusion device  200 . 
       FIG. 44  illustrates an occlusion device  911  also comprising an inverted mesh tube  913  and having an outer layer  914 , an inner layer  915 , and an inversion fold  916 , which creates a distal orifice  917 , and serves as the transition between the outer layer  914  and the inner layer  915 . The inverted mesh tube  913  has a first end  918  and a second end  919 . The occlusion device  911  includes a proximal section  920  and a distal section  921 . The proximal section  920  and distal section  921  have substantially flattened portions  922 ,  923 , and the distal section  921  has a distal hemisphere shape  924 , configured to contact an aneurysm dome. There is a waist  912  between the substantially flattened portions  922 ,  923 . The maximum diameter portion  926 , on the distal section  921 , has a diameter that is larger than the diameter of the maximum diameter portion  925 , on the proximal section  920 , and thus, the occlusion device  911  is configured to be implanted in an aneurysm having a larger dome (distal) portion and a smaller proximal portion of the aneurysm sac. The proximal section  920  of the occlusion device  911  includes a partially convex, partially concave shape  927  which may be configured to direct blood flow along the concave portion  928 , and also configured to interface with the proximal portion of the aneurysm at the convex portion  929 . Both the concave portion  928  and the convex portion  929  face substantially proximally. The occlusion device  911  may comprise any of the materials and be made with any of the processes described in relation to the occlusion device  200 . 
       FIG. 45  illustrates an occlusion device  931  also comprising an inverted mesh tube  932  and having an outer layer  933 , an inner layer  934 , and an inversion fold  935 , which creates a distal orifice  936 , and serves as the transition between the outer layer  933  and the inner layer  934 . The inverted mesh tube  932  has a first end  937  and a second end  938 . The occlusion device  931  includes a proximal section  939  and a distal section  940 . The proximal section  939  and distal section  940  have curvilinear portions  941 ,  942  facing each other, and the proximal section  939  has a hemisphere shape  943 , configured to contact a proximal wall of the aneurysm. The maximum diameter portion  945  of the distal section  940  has a diameter that is smaller than the diameter of the maximum diameter portion  944  of the proximal section  939 , and thus, the occlusion device  931  is configured to be implanted in an aneurysm having a smaller dome (distal) portion and a larger proximal portion of the aneurysm sac. The distal section  940  includes a smaller hemisphere shape  946 . The occlusion device  931  may comprise any of the materials and be made with any of the processes described in relation to the occlusion device  200 . 
     In  FIGS. 46-49 , an aneurysm  10  having a neck portion  16  is shown. The occlusion device  200  is shown in use being implanted by a user (e.g., physician) into the aneurysm  10  through the delivery catheter  150  to disrupt or halt the flow of blood flow between the blood vessel  12  and the internal volume  14  of the aneurysm, thereby reducing the likelihood that the aneurysm  10  will rupture (or if previously ruptured, reducing the likelihood of rerupture). The occlusion device  200  is configured to be low profile device, minimizing disruptions to surrounding bodies, such as a side branch  18  of the blood vessel  12 . The blood vessel  12  has a blood vessel wall  13  and the aneurysm  10  has an aneurysm wall  11 . In  FIG. 46 , the delivery catheter  150  is advanced through a sheath and/or guiding catheter (not shown) through a puncture or cutdown in a peripheral blood vessel, such as a femoral artery, a brachial artery, or a radial artery. The distal end  162  of the delivery catheter  150  may be shaped with a curve, as shown, either by the manufacturer, or prior to the procedure by the user, in order to allow for improved backup support when delivering the occlusion device  200 . The distal end  162  of the delivery catheter  150  is placed adjacent the neck portion  16  of the aneurysm  10 . The delivery catheter  150  may be advanced over a guidewire (not shown) that is passed through the lumen  148 . The guidewire may then be removed, leaving the lumen  148  as a delivery conduit and the delivery catheter  150  as a support column. 
     In  FIG. 47 , the occlusion device  200  is advanced through the lumen  148  of the delivery catheter  150 , as described, and the distal section  204  of the occlusion device  200  is advanced out of the lumen  148  and into the internal volume  14  of the aneurysm  10 . The distal end  230  is the first portion of the occlusion device  200  that exits the lumen  148  and thus is the first portion of the occlusion device to enter the aneurysm  10 . The distal end  230  is blunt, soft, and atraumatic and is configured to first contact the interior surface  15  of the aneurysm  10 . In  FIG. 48 , the occlusion device  200  is shown in a substantially expanded configuration within the internal volume  14  of the aneurysm  10 . The proximal section  202  is expanded against the interior surface  15  of the aneurysm  10 , and covers the neck portion  16  of the aneurysm. The distal section  204  is expanded against the interior surface  15  of the aneurysm  10 , and serves to anchor or stabilize the proximal section  202  in the aneurysm  10  and adjacent the neck portion  16 . 
     Also, in  FIG. 48 , the detachable joint  158  (see  FIG. 47 ) has been detached, and thus, the free end  154  of the pusher  152  can be pulled into the lumen  148  of the delivery catheter  150 . In some embodiments, the delivery catheter  150  is maintained over the detachable joint  158  during the detachment procedure, to further protect the aneurysm  10 . In  FIG. 49 , the delivery catheter  150  is removed, and the deployed occlusion device  200  is in place to begin to occlude the internal volume  14  of the aneurysm. The distal section  204  also serves to force the proximal section  202  against the neck portion  16  and/or against the interior surface  15 , see straight arrow in  FIG. 49 . The dual layer of mesh in the proximal section  202  at a lower portion  231  ( FIGS. 42 and 49 ) aid in the disruption of blood flow into the aneurysm  10 , thus causing thrombosis to isolate the internal volume  14  of the aneurysm  10  from blood flow through the blood vessel.  12 . The waist  222  helps the distal section  204  transmit force to the proximal portion  202 , though the maximum diameter portions  218 ,  226  are also configured to transmit force to the substantially flattened portions  220 ,  224 , or the substantially flattened portions  220 ,  224  transmit to each other, as the waist  222  is longitudinally compressed. The force (straight arrow) maintaining the proximal section  202  in place, further assures this process, and also protects against undesired compaction over time of the occlusion device  200 . The dual layers of mesh in the distal section  204  can aid in the healing of the dome. In an unruptured aneurysm, the contact with the dome can cause healing that can thicken the dome at this portion, where the dome is often at is thinnest, most stretched state. In a ruptured aneurysm, the contact with the dome can act like a bandage and accelerate or increase the healing process to further avoid a re-rupture. 
     The occlusion devices  260 ,  911 ,  931  of  FIGS. 43-45  are implanted into aneurysms  10  in a similar manner to the occlusion device  200  described in relation to the implantation procedure of  FIGS. 46-49 . Alternative embodiments of the occlusion devices  200 ,  260 ,  911 ,  931  from  FIGS. 41-45  are shown in  FIGS. 50-53 . Occlusion devices  947 ,  950 ,  954 ,  958  are each similar to occlusion devices  200 ,  260 ,  911 ,  931 , respectively, except that the inner layers  948 ,  951 ,  955 ,  959  do not follow the contours of the outer layers  949 ,  952 ,  956 ,  960 , but instead are substantially straight tubular columns. These columns may be the diameter of the original tubular mesh (as braided), or may be an expanded diameter (as heat formed). The inner layers  948 ,  951 ,  955 ,  959  can each provide additional column strength and longitudinal support, which can help to apply a force against the aneurysm neck portion  16  with the proximal sections  391 ,  953 ,  957 ,  961 . 
       FIG. 54  illustrates an occlusion device  400  being implanted within an angulated sidewall aneurysm  19  having a dome  21  that is off axis from the neck portion  16 . This may be approximated by angle A. The occlusion device  400  is similar to the occlusion device  200 , and has a proximal section  402  that is separated from the distal section  404  by an elongate flexible extension  406 . The flexible extension  406  may be similar to the central waist  222  of the occlusion device  200 , but the diameter and the length may be varied in order to change its flexibility characteristics, and to change to total amount of angulation possible between the proximal section  402  and the distal section  404 . The construction of the occlusion device  400  may be identical to any of the embodiments described in relation to the occlusion devices  200 ,  260 ,  911 ,  931 ,  947 ,  950 ,  954 ,  958  of  FIGS. 42-45 and 50-53 , however, the longer, more flexible extension  406  allows the distal section  404  to more readily angulate with respect to the proximal section  402 . It also allows for a larger amount of angulation between the proximal section  402  and the distal section  404 , because of the larger amount of space between them (e.g., because of increased longitudinal distance). Thus, the occlusion device  400  is capable conforming to a large number of different aneurysm shapes or aneurysm angular takeoff angles or general angulations. The occlusion device  400  may be configured to allow for an angle A of between 90° and 180°, or between about 135° and about 180°. Thus, the angle A is changeable to a minimum angle of between about 90 degrees and about 135 degrees. If the elongate flexible extension  406  is long enough, an angulation of less than 90° may even be possible, which might occur in some aneurysms with very odd shapes. The substantially flattened portions may have slight angulations or tapers, as do the substantially flattened portions  220 ,  224 ,  276 ,  278  of  FIGS. 42-43  or those in  FIGS. 50-51 , with the longitudinal space increasing toward the outer diameters, such that the angle A ( FIG. 54 ) is decreased even further. The total longitudinal length of the flexible extension  406  can be between about 0.5 mm and about 30 mm, or between about 0.5 mm and about 25 mm, or between about 1 mm and about 10 mm, or between about 1 mm and about 6 mm, or between about 1 mm and about 3 mm. For cerebral aneurysms, the occlusion device  400  may be configured such that the proximal section  402  and the distal section  404  are each substantially hemispherical in shape, but that the flexible extension, when straight, provides an elongated, revolved oval profile. For example, with the proximal section  402  and the distal section  404  each having a hemisphere shape of about 6 mm in diameter, a 1 mm long flexible extension  406  begets a 7 mm long by 6 mm diameter implant. A 2 mm long flexible extension  406  begets an 8 mm long by 6 mm diameter implant. A 3 mm long flexible extension  406  begets a 9 mm long by 6 mm diameter implant. A wide range of sizes is possible, and the diameter of the proximal section  402  may differ from the diameter of the distal section  404  or they may be substantially the same as each other. 
       FIG. 55  illustrates an occlusion device  410  implanted within an angulated sidewall aneurysm  19  via a delivery catheter  417 . The occlusion device  410  is similar to the occlusion device  400  of  FIG. 54 , except the elongate extension  416 , extending between the proximal section  412  and the distal section  414 , has a bellows configuration that further aids its bendability. Both the inner and outer layer of the mesh tube may include the bellows-type feature, or only the outer layer may include this feature. In alternative embodiments, the flexible section  406  or elongate extension  416  (e.g., comprising a bellows-type feature) can have an outer diameter that varies along its longitudinal axis. For example, the outer diameter may get gradually smaller in the center and larger on the ends and thus have a concave cylindrical shape or hourglass shape. Alternatively, the outer diameter may get gradually larger in the center and smaller on the ends and thus have a convex cylindrical shape or American football shape.  FIG. 56  illustrates an occlusion device  450  implanted within an aneurysm  452 . The aneurysm  452  is terminal to a main artery  454 , and several connecting arteries  456 ,  458 ,  460 ,  462 . The occlusion device  450  of  FIG. 56  has a proximal section  464  and a distal section  466 , separated by an elongated flexible extension  468 . The proximal section  464  includes a hemispheric proximal end  470  and a concavity  472  distally, opposite the proximal end  470 . The distal section  466  includes a hemispheric distal end  474  and a concavity  476  proximally, opposite the distal end  474 . The distal section  466  and the proximal section  464  are each able to pivot (away from the longitudinal axis) in relation to the elongated flexible extension  468 , which allows the occlusion device  450 , when delivered into the aneurysm  452 , to conform to the shape of the inner contours of the aneurysm  452 , and thus more snugly fit into the aneurysm  452 . As shown in  FIG. 56 , an apex  478  the distal section  466  of the occlusion device  450  is slightly pivoted back, and to the right. The proximal section  464  is slightly pivoted forward. The proximal section  464  has a maximum diameter that is larger than the diameter or transverse dimension of the aneurysm neck  480 . The maximum diameter of the proximal section  464  may also be configured to be oversized in relation to the aneurysm sac, in order to apply a gripping radial force. The same is true of the distal section  466 . Once in the preferred position within the aneurysm  452 , the occlusion device  450  is then detached from the pusher  415 . 
       FIG. 57  illustrates an occlusion device  482  being implanted within an aneurysm  484 . The occlusion device  482  of  FIG. 57  is similar to the occlusion device  200  of  FIGS. 41-42 , but has slightly different dimensions. As the occlusion device  482  is implanted within the aneurysm, the distal section  486  and the proximal section  488  are compressed longitudinally together. The waist  490  is able to deform somewhat (e.g., shorten and widen) to allow the dynamic shaping of the occlusion device  482  to occur when implanted into the aneurysm  484 . The proximal section  488  is forced (straight arrow) against the neck  492 . The substantially flattened portion  494  of the proximal section  488  and the substantially flattened portion  496  of the distal section  486  are each able to flex to form ring-shaped concavities. The flexing acts as a spring, to maintain the force of the proximal section  488  against the neck  492 . An occlusion device  401  having a relatively wider waist  403  and relatively longer flexible extension  405  between its proximal section  407  and its distal section  409 . is shown in  FIG. 58 . The waist  403  of the occlusion device of  FIG. 58  has a circumferentially extending concavity (hourglass shape) and comprises a hemispherical proximal face  411  and a hemispheric distal face  413 . The occlusion devices of  FIGS. 56-58  are shown still coupled to the pusher  415  and being delivered through a delivery catheter  417 .  FIGS. 59-61  illustrate three different configurations of an occlusion device  962 . In  FIG. 59 , the occlusion device  962 , as heat-formed, is in a completely unrestrained, expanded configuration. In  FIG. 60 , the occlusion device  962  is constrained within a microcatheter lumen  980 . In  FIG. 61 , the occlusion device  962  has been delivered into an aneurysm  748 . 
       FIG. 59  illustrates an occlusion device  962  comprising a proximal section  963  and a distal section  964  and a waist  971 , all constructed of a single, continuous dual layer mesh. The occlusion device  962  is constructed from an inverted mesh tube  965  having a first end, a second end, and a wall (as in the occlusion device of  FIGS. 41-42 ). The inverted mesh tube  965  extends on an outer layer  966  past a proximal end  967  of the proximal section  963  and along a hemisphere shape  968  to a maximum diameter portion  969  having an acute angulation  719 . From the maximum diameter portion  969 , the outer layer  966  extends radially inward along a substantially flattened portion  970  to the central waist  971 . The outer layer  966  then extends radially outward along a substantially flattened portion  972  of the distal section  964  to a maximum diameter portion  973  having an acute angulation  727  to a hemisphere shape  728  to a distal end  974  of the occlusion device  962 . The hemisphere shape  728  is configured to contact at least a portion of an aneurysm dome. The maximum diameter portion  973  has a diameter that is about equal to the diameter of the maximum diameter portion  969 , but in other embodiments, they may differ. At the distal end  974 , the wall  709  is inverted inwardly at an inversion fold  975 , which creates a distal orifice  976  and an internal volume  977 . The wall  709  transitions at the inversion fold  975  from the outer layer  966  to an inner layer  978  which follows the contours of the outer layer  966  from the distal orifice  976  to the first end. The occlusion device  962  is shown coupled to an elongate pusher  701  and a marker band  705 . 
     In  FIG. 59 , the occlusion device  962  is shown unrestrained. Thus, if the mesh tube  965  is formed of at least some nickel-titanium, or shape memory alloy, filaments, braided together, the shape shown in  FIG. 59  can be heat formed, as described herein. The occlusion device  962 , in its compressed configuration, is shown in  FIG. 60 , inserted through the lumen  980  of a delivery catheter  979  having a distal end  981  and a proximal end  746 .  FIG. 61  shows the occlusion device  962  within an aneurysm  748  having a neck  982  and a dome  983 . The proximal section  963  and a distal section  964  are each deformed from contact with the aneurysm wall  984 , thus confirming to the aneurysm wall  984  in a snug manner. The overall length L 2  of the occlusion device  962  becomes less than the original length L 1  ( FIG. 59 ) because of longitudinal compressive forces F applied in return by the aneurysm wall  984 . Thus, the overall shape of the occlusion device within the aneurysm  748  in  FIG. 61  becomes more spherical than that of the unrestrained shape in  FIG. 59 . The proximal end  967  and the marker band  705  are at or adjacent the neck  982  of the aneurysm  748 , while the distal section  964  is adjacent the dome  983 .  FIG. 61  also shows a remnant  703  of the pusher  701  after detachment has occurred. In some embodiments, no remnant of the pusher  701  remains after detachment. The occlusion device  962  is very conformable with different aneurysmal shapes and sizes. Because of this, the occlusion device  962  may also fit into an aneurysm that is longitudinally longer and diametrically narrower than the aneurysm  748  of  FIG. 61 . It may also fit into an aneurysm that has a significantly non-symmetric shape. 
     Turning to  FIG. 62 , an occlusion device  985  is constructed from an inverted mesh tube  986  having a first end  987 , a second end  988 , and a wall  989 . The inverted mesh tube  986  extends on an outer layer  990  from the second end  988  past a proximal end  991  of the proximal section  992  and along a lower mushroom shape  993  to a maximum diameter portion  994 . From the maximum diameter portion  994 , the outer layer  990  extends radially inward along the mushroom shape  988  to a first central waist  995 . The outer layer  990  then extends radially outward along a globular portion  996  having a maximum diameter portion  997  and then to a second central waist  998 . Though the globular portion  996  of the occlusion device  985  is relatively short and wide, in other embodiments, the opposite might be true, with the globular portion  996  having more of an American football shape. In other embodiments, the globular portion  996  may have a generally spherical shape. The outer layer  990  then forms an upper mushroom shape  999  having a maximum diameter  640  to a distal end  641  of the occlusion device  985 . The hemisphere shape  642  of the upper mushroom shape  999  is configured to contact an aneurysm dome. The maximum diameter  640  is about equal to the maximum diameter  997 , but in other embodiments, they may differ. The occlusion device  985  is substantially cylindrically symmetric around a central axis Z. However, in alternative embodiments, there may be certain portions of asymmetry, such as one or more indented or extended feature at a particular location in a perimeter. At the distal end  641 , the wall  989  is inverted inwardly at an inversion fold  643 , which creates a distal orifice  644  and an internal volume  645 . The wall  989  transitions at the inversion fold  643  from the outer layer  990  to an inner layer  646  which follows the contours of the outer layer  990  from the distal orifice  644  to the first end  987 . The occlusion device  985  is fabricated as an inverted mesh tube  986  having a simple straight elongate configuration, and is subsequently formed into the shape shown in  FIG. 62  and heat set into this shape. Each of the three sections, a proximal section  594 , a central section  596 , and a distal section  598 , are shown in  FIG. 62  in their expanded configurations, but are configured to be compressed or compacted within the lumen  148  of a delivery catheter  150  (e.g., microcatheter). The proximal end  991 , located on the lower portion of the proximal section  594  has a flat surface  599  or substantially flat surface, and is configured for engaging, and even gripping, the aneurysm neck at the interior portion of the aneurysm. The engagement of the aneurysm neck by the flat surface  599  or substantially flat surface may help seal the aneurysm and help prevent an endoleak. The globular portion  996 /central section  596  is configured to allow the angulation between the proximal section  594  and the distal section  598 , while providing some body, or a stop/limit in between. 
     In some embodiments, one or more of the proximal section  594 , central section  596 , or distal section  598  may comprise some nickel-titanium alloy filaments and some radiopaque elements, comprising platinum, gold, tantalum, or alloys of any of these or other radiopaque materials. In some embodiments, the filaments may comprise drawn filled tubes, such as those comprising a nickel-titanium alloy outer wall and a platinum core. The radiopaque material allows the occlusion device  985  to be visible on radiographs or fluoroscopy. The occlusion device  985  may be configured by controlling how much radiopaque material is used, by either the ratio of radiopaque filaments to non-radiopaque filaments, or by the amount of platinum core in the drawn filled tubes. In this manner, the occlusion device  985  can be selectively fabricated to be sufficiently visible, but not over visible, e.g., overly bright, such that other objects are obscured. In some embodiments, whether any of the filaments comprise radiopaque materials or not, a marker band may be attached to the first end  987  and/or second end  988  of the inverted mesh tube  986 , by adhesive or epoxy bonding, or swaging, welding or other mechanical attachment. 
       FIG. 63  illustrates an occlusion device  647  having an inverted mushroom-shaped proximal section  648 , a globular central section  649 , and a mushroom-shaped distal section  650  having a distal apex  81 . Each of the sections  648 ,  649 ,  650  are separated by central waists  651 ,  653 . Sections  648 ,  649  are separated by central waist  651  and sections  649 ,  650  are separated by central waist  653 . Each of the sections  648 ,  649 ,  650  are formed from braided mesh  607  having different stiffness characteristics from each other. Though the sections  648 ,  649 ,  650  are fully braided, the braiding is only shown in windows  654 ,  655 ,  656  for simplicity. The proximal section  648  is braided such that it is stiffer than either the central section  649  or the distal section  650 . The proximal section  648  may be braided by larger diameter filaments, and/or may be braided with larger braid angles, to achieve the increased stiffness. The increased stiffness is configured for securely wedging or setting against the aneurysm neck, for example, to achieve better closure or disruption at the entry to the aneurysm. The distal section  650  is braided such that it is less stiff/more flexible than either the central section  649  or the proximal section  648 . The distal section  650  may be braided by smaller diameter filaments, and/or may be braided with smaller braid angles, to achieve the decreased stiffness. The decreased stiffness is configured for softly setting against the aneurysm dome. This is particularly helpful in avoiding a rupture of an aneurysm, for example, a high-risk aneurysm. A high-risk aneurysm may have a substantially large diameter, or a substantially thin wall at the dome. Another high-risk aneurysm may be a previously ruptured aneurysm that has at least partially healed, but which may be prone to rerupture. The central section  649  may be braided by filaments, and/or may be braided with braid angles, that achieve an intermediate stiffness to the proximal section  648  and the distal section  650 . Changes in wire/filament diameter be may be created after forming the braided mesh  607  from a single set of wires, by adjusting or rearranging the braid crossings. In some embodiments, the distal section  650  may be subsequently etched (chemical etch, photochemical etch) to decrease the overall wire diameter and decrease the stiffness. In some embodiments, both the distal section  650  and the central section  649  are etched in a first etching operation. Then, only the distal section  650  is etched in a second etching operation. This, as originally formed, the proximal section  659 , central section  649 , and distal section  650  are formed from wires having the same diameter, but after the two etching operations, the distal section  650  has smaller diameter wires than the central section  649  and the central section  649  has smaller diameter wires than the proximal section  648 . Thus, in some embodiments, the distal section  650  may be made more flexible than the proximal section  648  via etching alone. 
       FIG. 64  illustrates an occlusion device  1000  having a proximal end  1002  and a distal end  1004  and configured for placement within an aneurysm. The occlusion device  1000  comprises a lower portion  1006  having a proximal outer diameter A and a distal outer diameter B and a tapered frustoconical section  1008  extending between diameter A and diameter B. In some embodiments, the lower portion  1006  is circular, with substantially the same diameter at any transverse slice (around the perimeter). In other embodiments, the lower portion  1006  is non-circular, and may comprise an ellipse, an oval, a polygon or other shapes. The tapered frustoconical section  1008  is configured to be larger than a maximum transverse dimension of an opening into the aneurysm (the neck portion) at at least some portion between A and B. In some embodiments, the diameter A is configured to be larger than a maximum transverse dimension of an opening into the aneurysm (the neck portion). Thus, the lower portion  1006  is configured to completely cover the neck portion, and thus to cause stagnation of blood within the aneurysm, leading to occlusion. The occlusion device  1000  is constructed from a mesh (braided) Nitinol (nickel-titanium alloy) tube  1005  that is inverted on itself. The mesh tube  1005  has a first end and a second end. The second end is folded back over the outer diameter of the first end thus providing an outer facing surface  1003  and an inner facing surface (not visible in  FIG. 64 ). The mesh tube  1005  is heat-formed such that the occlusion device  1000  comprises several expanded portions: the lower portion  1006 , an upper portion  1010 , and an intermediate waist portion  1012 . The upper portion  1010  has a length L, a maximum diameter C MAX  and a minimum diameter C MIN . The waist portion  1012  has a diameter D and a length g. 
     Particular ratios of the dimensions of the occlusion device  1000  have been found to be effective in creating a simple, easily-formed structure (body) that is particularly suited to be placed within aneurysms that may have at least one elongated dimension. For example, an aneurysm that is deep and narrow, or an aneurysm that is wide and short. The length of L of the upper portion  1010  may range from between about 1 mm to about 25 mm. The diameter C may range from between about 1 mm and about 25 mm. The diameter B may range from between about 1 mm and about 25 mm. The diameter A may range from between about 1 mm and about 24 mm. Generally, the diameter C is between about 50% to about 100% of the diameter B. Furthermore, generally, the diameter A is between about 50% to about 100% of the diameter B. In some embodiments, the diameter A is between about 70% and about 90% of the diameter B. 
     As formed (e.g., heat-formed), the occlusion device  1000  has an expanded configuration (shown in  FIG. 64 ) and a collapsed configuration, configured for delivery through the lumen of a delivery catheter (e.g., microcatheter). The occlusion device  1000  comprises two mesh layers, provided by the outer facing surface  1003  and the inner facing surface. In some embodiments, the occlusion device  1000  may comprise some nickel-titanium alloy filaments and some radiopaque elements, comprising platinum, gold, tantalum, or alloys of any of these or other radiopaque materials. In some embodiments, the filaments may comprise drawn filled tubes (DFT), such as those comprising a nickel-titanium alloy outer wall and a platinum core. The radiopaque material allows the occlusion device  1000  to be visible on radiographs or fluoroscopy. The occlusion device  1000  may be configured by controlling how much radiopaque material is used, by either the ratio of radiopaque filaments to non-radiopaque filaments, or by the amount of platinum core in the drawn filled tubes. In this manner, the occlusion device  1000  can be selectively fabricated to be sufficiently visible, but not over visible, e.g., overly bright, such that other objects are obscured. In some embodiments, whether any of the filaments comprise radiopaque materials or not, a marker band may be attached to the proximal end  1002  of the occlusion device  1000 , by adhesive or epoxy bonding, or swaging, welding or other mechanical attachment. The drawn filled tubes (DFT) may each have a platinum core that has a cross-sectional area that is between about 10% and about 70% of the total cross-sectional area of the DFT. In some embodiments, all (100%) of the filaments may comprise DFTs. In other embodiments, between 50% and 100% of the filaments may comprise DFTs, with the remainder of the filaments comprising only nickel-titanium alloy. 
     Turning to  FIG. 65 , the occlusion device  1000  may be coupled at or near its proximal end  1002  to a pusher  152 , having a distal end  154  and a proximal end  156 . The pusher  152  may comprise a wire, a hypo tube, or another elongate structure having column support is detachably coupled at its distal end  154  to the proximal end  1002  of the occlusion device  1000 . A detachable joint  158  may comprise one of a number of detachment systems, including but not limited to pressurized detachment, electrolytic detachment mechanisms, hydraulic detachment mechanisms, mechanical or interlocking detachment mechanisms, chemical detachment mechanisms, heat-activated detachment systems, or frictional detachment systems. During delivery, the pusher  152  is held on its proximal end  156  by a user and pushed in a forward longitudinal direction in order to advance the occlusion device  1000  to the distal end of a delivery catheter (e.g., a microcatheter) having a delivery lumen. The delivery catheter may also include a proximal hub, such as a luer connector. 
       FIG. 66  illustrates a first view of the occlusion device  1000  delivered into a first aneurysm configuration  1020  comprising an aneurysm  1022 , a neck  1024 , a first parent vessel arm  1026 , a second parent vessel arm  1028 , and an additional connecting vessel  1030 .  FIG. 67  illustrates a different view. The waist portion  1012  allows some flexure between the upper portion  1010  and the lower portion  1006 , and thus the upper portion  1010  is able to be somewhat compressed into the lower portion  1006 , as seen in  FIGS. 66 and 67 . Thus, the lower portion  1006  protects and covers the neck  1024  of the aneurysm  1022  while the upper portion  1010  allows the occlusion device  1000  to adapt to the shape of the aneurysm  1022  for a snug by safe fit. The waist portion  1012  also acts as a shock absorber. 
       FIG. 68  illustrates an occlusion device  800  also comprising an inverted mesh tube  802  and having an outer layer  804 , an inner layer  806 , and an inversion fold  808 , which creates a distal orifice  810 , and serves as the transition between the outer layer  804  and the inner layer  806 . The inverted mesh tube  802  has a first end  812  and a second end  814 . The occlusion device  800  includes a proximal section  816 , a distal section  818 , and an intermediate section  820 . The proximal section  816  has a substantially flattened portion  822 , and the distal section  818  has a globular shape  824 , configured to contact an aneurysm dome. The intermediate section  820  also has a globular shape  826 . There is a waist  828  between the proximal section  816  and the intermediate section  820 , and a circumferentially extending concavity  830  between the distal section  818  and the intermediate section  820 . The proximal section  816  includes a proximal concavity  832  concavity, which is configured to clear a marker band  834 . The proximal section  816  has a maximum diameter  836  configured to grip and internal wall of an aneurysm. The occlusion device  800  comprises a cover  838  configured to seat adjacent a neck of the aneurysm. In some embodiments, the cover  838  is circular, with substantially the same diameter at any transverse measurement around the perimeter. In other embodiments, the cover  838  is non-circular, and may comprise an ellipse, an oval, a polygon or other shapes. In the non-circular embodiments, the cover  838  comprises a minimum transverse dimension and a maximum transverse dimension. In the particular case of an ellipse or an oval shape, the cover  838  comprises a major diameter and a minor diameter. The minor diameter or minimum transverse dimension is configured to be larger than a maximum transverse dimension of an opening into the aneurysm (the neck portion). Thus, the cover  838  is configured to completely cover the neck portion, and thus to cause stagnation of blood within the aneurysm, leading to occlusion. The cover  838  is constructed from a mesh (braided) Nitinol (nickel-titanium alloy) tube  840  that is inverted on itself. The mesh tube  840  has a first end  842  and a second end  844 . The second end  844  is folded back over the outer diameter of the first end  842 . The mesh tube  840  is heat-formed such that cover  838  comprises an expanded portion  843  and the first end  842  and second end  844  comprise unexpanded (or partially expanded) portions. The cover  838  is fabricated as an inverted mesh tube  840  having a simple straight elongate configuration, and is subsequently formed into the shape shown in  FIG. 68 , and heat set into this shape. For example, the inverted mesh tube  840  may be constructed as a single layer mesh tube formed of at least some nickel-titanium alloy filaments, and then inverted on itself. The inverted mesh tube  840  may then be placed into a die or mold comprising one or more pieces, to hold it in the shape of the cover  838 . Then, the cover  838  may be subjected to an elevated temperature and then cooled, to lock in the shape, resulting in a cover  838  having at least some superelastic properties. 
     The occlusion device  800  may comprise any of the materials and be made with any of the processes described in relation to the occlusion device  200 , or any other of the occlusion devices described herein. The occlusion device  800  is configured to have flexing or articulating capabilities at the waist  828  and at the circumferentially extending concavity  830  which thus allow the proximal section  816 , the distal section  818 , and the intermediate section  820  to bend and conform to aneurysms of complex and irregular shapes. The maximum diameter  836  is configured to apply a radial force to the aneurysm wall to keep the occlusion device  800  in place, while the cover  838  facilitates thrombosis and closure of the aneurysm at the neck. 
     While the foregoing is directed to embodiments of the present disclosure, other and further embodiments may be devised without departing from the basic scope thereof. The filament diameter of the filaments comprising any of the mesh material (e.g., mesh tube including inverted mesh tubes) described herein may be between about 0.0004 inch and about 0.003 inch, or between about 0.0005 inch and about 0.002 inch, or between about 0.0006 inch and about 0.002 inch, or between about 0.0006 inch and about 0.0015 inch. The drawn filled tubes (DFT) may comprise between 0% and 100% of the total strands/filaments in any of the braided/mesh tubes. In some embodiments, the drawn filled tubes (DFT) comprise about 50% to about 100% of the total filaments of the cover and about 50% to about 100% of the total filaments of each of the doubled-over or looped tubular mesh. The radiopaque core of each of at least some of the drawn filled tubes has a cross-sectional area that is between about 10% and about 70% of the total cross-sectional area of the each of at least some of the drawn filled tubes, or between about 51% and about 70% of the total cross-sectional area of the each of at least some of the drawn filled tubes. In some embodiments, NiTi #1-DFT® wire produced by Fort Wayne Metals Research Products Corp. (Fort Wayne, Ind. USA) may be utilized. The filaments may be braided with patterns having filament crossings that are in any one or more of the following ratios of filaments: 1×1, 1×2, 2×1, 2×2, 2×3, 3×2, 3×3, etc. (e.g., warp and weft). Any low, moderate, or high pick counts may be used, for example, between about 15 picks per inch and about 300 picks per inch, or between about 20 picks per inch and about 160 picks per inch. Any of the filaments or any of the portion of the occlusion devices may be coated with compounds that enhance endothelialization, thus improving the healing process when implanted within the aneurysm, and optimizing occlusion. The pusher and occlusion device configurations presented herein may also be used for in other types of implantable devices, such as stents, flow diversion devices, filters, and occlusion devices for structural heart defects. 
     In some embodiments, braided elements may be subsequently etched (chemical etch, photochemical etch) to decrease the overall wire diameter and decrease the stiffness. 
     Additional materials may be carried on the cover of the occlusion device, or any other proximal portion of the occlusion device, and configured to face opposite the aneurysm neck. In some embodiments, the material on the occlusion device may comprise a biological layer, configured to encourage growth. In some embodiments, the biological layer may comprise antibodies, in order to accelerate the formation of an endothelial layer, for example, by attracting endothelial progenitor cells (EPCs). In some embodiments, the biological layer may comprise a natural membrane or structure, such as a membrane, such as a membrane from an ear, or a cornea, or an ultra-thin piece of ligament, or even a piece of blood vessel wall. In some embodiments, the material on the occlusion device may comprise a polymer layer configured to act as a simulated arterial wall. In some embodiments, the polymer layer may comprise polytetrafluoroethylene, such as expanded polytetrafluoroethylene (ePTFE), such as that used in grafts. Occlusion devices as described herein may incorporate biological or polymeric layers. 
     The following clauses include examples of apparatus of the disclosure. 
     Clause 101: In one example, an apparatus for treating an aneurysm in a blood vessel includes an occlusion element configured to be releasably coupled to an elongate delivery shaft, the occlusion element including a mesh body configured to be delivered in a collapsed configuration through an inner lumen of a delivery catheter, the inner lumen having a proximal end and a distal end, the body further configured to expand to an expanded configuration when advanced out of the distal end of the inner lumen of the delivery catheter and into the aneurysm, wherein the body includes a proximal portion having a proximal maximum transverse dimension A and a distal maximum transverse dimension B and a frustoconical portion extending between the proximal maximum transverse dimension A and the distal maximum transverse dimension B, and wherein the body further includes distal portion having a maximum transverse dimension C and a waist portion between the proximal portion and the distal portion, and wherein the dimension A is between about 50% and about 100% of dimension B. 
     Clause 102: In some examples, the apparatus includes clause 101, wherein the dimension A is between about 70% and about 90% of dimension B. 
     Clause 103: In some examples, the apparatus includes clause 101, wherein the dimension C is between about 50% and about 100% of dimension B. 
     Clause 104: In another example, an apparatus for treating an aneurysm in a blood vessel, includes an occlusion element configured to be releasably coupled to an elongate delivery shaft, the occlusion element including an inverted mesh tube having an outer layer and an inner layer, the outer layer transitioning to the inner layer at an inversion fold, wherein at least the outer layer is formed into an expanded shape having a proximal section having a first diameter, a distal section having a second diameter, and a waist portion having a third diameter, wherein the third diameter is less than the first diameter and the third diameter is less than the second diameter. 
     Clause 105: In some examples, the apparatus includes clause 104, wherein the inner layer has an expanded shape which conforms with the expanded shape of the outer layer. 
     Clause 106: In some examples, the apparatus includes either one of clauses 104 or 105, wherein the first diameter is about equal to the second diameter. 
     Clause 107: In some examples, the apparatus includes either one of clauses 104 or 105, wherein the first diameter is greater than the second diameter. 
     Clause 108: In some examples, the apparatus includes either one of clauses 104 or 105, wherein the first diameter is less than the second diameter. 
     Clause 109: In some examples, the apparatus includes any one of clauses 104-108, wherein distal section has a substantially hemispherical shape. 
     Clause 110: In some examples, the apparatus includes any one of clauses 104-109, wherein the proximal section has a substantially hemispherical shape. 
     Clause 111: In some examples, the apparatus includes any one of clauses 104-109, wherein the proximal section includes a proximal portion having a concave conical shape. 
     Clause 112: In some examples, the apparatus includes any one of clauses 104-111, wherein the inversion fold is a circular shape surrounding an orifice that communicates with an internal volume of the occlusion element. 
     Clause 113: In some examples, the apparatus includes clause 111, wherein the concave conical shape is configured to guide blood flow within a native blood vessel adjacent to an aneurysm when the occlusion element is substantially implanted within the aneurysm. 
     Clause 114: In some examples, the apparatus includes any one of clauses 104-113, wherein the proximal section and the distal section are configured to flex with respect to each other so that they do not share the same longitudinal axis. 
     Clause 115: In some examples, the apparatus includes clause 114, wherein the waist portion is provided by an elongate tubular section. 
     Clause 116: In some examples, the apparatus includes either one of clauses 114 or 115, wherein the waist portion is provided by a bellows-shaped element. 
     Clause 117: In some examples, the apparatus includes any one of clauses 114-116, wherein a longitudinal axis of the proximal section and a longitudinal axis of the distal section are configured to be moveable between 900 and 180°. 
     Clause 118: In some examples, the apparatus includes clause 117, wherein a longitudinal axis of the proximal section and a longitudinal axis of the distal section are configured to be moveable between 135° and 180°. 
     Clause 119: In some examples, the apparatus includes clause 115, wherein the tubular section has a length of between about 1 mm and about 10 mm. 
     Clause 120: In some examples, the apparatus includes clause 115, wherein the tubular section has a length of between about 1 mm and about 6 mm. 
     Clause 121: In some examples, the apparatus includes clause 115, wherein the tubular section has a length of between about 1 mm and about 3 mm. 
     Clause 122: In some examples, the apparatus includes any one of clauses 104-121, wherein the occlusion element includes a nickel-titanium alloy. 
     Clause 123: In some examples, the apparatus includes any one of clauses 104-122, wherein the occlusion element includes a radiopaque material. 
     Clause 124: In some examples, the apparatus includes clause 123, wherein the radiopaque material includes a marker band. 
     Clause 125: In some examples, the apparatus includes clause 124, wherein the marker band is coupled to the proximal section. 
     Clause 126: In another example, an apparatus for treating an aneurysm in a blood vessel, including an occlusion element configured to be releasably coupled to an elongate delivery shaft, the occlusion element including an inverted mesh tube having an outer layer and an inner layer, the outer layer transitioning to the inner layer at an inversion fold, wherein at least the outer layer is formed into an expanded shape having a proximal section having a first diameter, a distal section having a second diameter, and a first waist portion having a third diameter, a middle section having a fourth diameter, and a second waist portion having a fifth diameter, wherein the first diameter, the second diameter, and the fourth diameter are each greater than the third diameter, and wherein the first diameter, the second diameter, and the fourth diameter are each greater than the fifth diameter. 
     Clause 127: In some examples, the apparatus includes clause 126, wherein the proximal section has a first stiffness and the distal section has a second stiffness, the first stiffness greater than the second stiffness. 
     Clause 128: In some examples, the apparatus includes clause 127, wherein the middle section has a third stiffness, the third stiffness greater than the second stiffness, and wherein the first stiffness is greater than the third stiffness. 
     Clause 129: In some examples, the apparatus includes any one of clauses 126-128, wherein the proximal section includes a set of filaments each having a diameter greater than filaments in the distal section. 
     Clause 130: In another example, a method for forming an apparatus for treating an aneurysm in a blood vessel, includes forming a mesh tube, inverting the mesh tube to form an outer layer and an inner layer, the outer layer transitioning to the inner layer at an inversion fold, forming at least the outer layer into an expanded shape having a proximal section having a first diameter and a distal section having a second diameter, and etching the distal section to decrease its stiffness. 
     Clause 131: In some examples, the method includes clause 130, wherein after the etching step, the distal section has a stiffness less than the stiffness of the proximal section. 
     Clause 132: In another example, an apparatus for treating an aneurysm in a blood vessel, includes an occlusion element configured to be releasably coupled to an elongate delivery shaft, the occlusion element including an inverted mesh tube having an outer layer and an inner layer, the outer layer transitioning to the inner layer at an inversion fold, the occlusion element configured to be delivered in a collapsed configuration through an inner lumen of a delivery catheter, the inner lumen having a proximal end and a distal end, the occlusion element further configured to expand to an expanded configuration when advanced out of the distal end of the inner lumen of the delivery catheter and into the aneurysm, wherein in the expanded configuration, at least the outer layer of the inverted mesh tube is formed into an expanded shape including a proximal section having a first transverse dimension, a distal section having a second transverse dimension, and a waist portion having a third transverse dimension, wherein the third transverse dimension is less than the first transverse dimension, and the third transverse dimension is less than the second transverse dimension, and wherein in the expanded configuration, the waist portion is configured to be deformed by an externally applied force such that a distance between the distal section and the proximal section is decreased. 
     Clause 133: In some examples, the apparatus includes clause 132, wherein the waist portion, in a substantially undeformed state, has a longitudinal length of between about 0.05 mm and about 25 mm. 
     Clause 134: In some examples, the apparatus includes clause 132, wherein the distal section has a length of between about 1 mm and about 25 mm. 
     Clause 135: In some examples, the apparatus includes clause 132, wherein the distal section has a first longitudinal axis and the proximal section has second longitudinal axis, and wherein in the expanded configuration, the waist portion is configured to be deformed by an externally applied moment such that an angle between the first longitudinal axis and the second longitudinal axis is changed. 
     Clause 136: In some examples, the apparatus includes clause 135, wherein the angle between the first longitudinal axis and the second longitudinal axis is changeable to a minimum angle of between about 90 degrees and about 135 degrees. 
     Clause 137: In some examples, the apparatus includes clause 132, wherein the waist portion includes a bellows shape. 
     Clause 138: In some examples, the apparatus includes clause 132, wherein the waist portion includes a circumferential concavity. 
     Clause 139: In some examples, the apparatus includes clause 132, wherein the proximal portion includes a proximal diameter A and a distal diameter B, and wherein the distal portion includes a diameter C, and wherein diameter A is between about 50% and about 100% of diameter B. 
     Clause 140: In some examples, the apparatus includes clause 139, further including a frustoconical portion extending between diameter A and diameter B. 
     Clause 141: In some examples, the apparatus includes clause 139, wherein diameter A is between about 70% and about 90% of diameter B. 
     Clause 142: In some examples, the apparatus includes clause 139, wherein diameter C is between about 50% and about 100% of diameter B. 
     Clause 143: In some examples, the apparatus includes clause 132, wherein the inner layer has an expanded shape which conforms with the expanded shape of the outer layer. 
     Clause 144: In some examples, the apparatus includes clause 132, wherein the first transverse dimension is about equal to the second transverse dimension. 
     Clause 145: In some examples, the apparatus includes clause 132, wherein the first transverse dimension is greater than the second transverse dimension. 
     Clause 146: In some examples, the apparatus includes clause 132, wherein distal section has a substantially hemispherical shape. 
     Clause 147: In some examples, the apparatus includes clause 132, wherein the proximal section has a substantially hemispherical shape. 
     Clause 148: In some examples, the apparatus includes clause 147, wherein distal section has a substantially hemispherical shape. 
     Clause 149: In some examples, the apparatus includes clause 132, wherein the inversion fold is a circular shape surrounding an orifice that communicates with an internal volume of the occlusion element. 
     Clause 150: In some examples, the apparatus includes clause 132, wherein the distal section has a generally cylindrical shape and a blunt distal end. 
     Clause 151: In some examples, the apparatus includes clause 132, wherein the distal section has a length that is greater than the second transverse dimension. 
     Clause 152: In some examples, the apparatus includes clause 132, wherein the inverted mesh tube is formed from a plurality of filaments. 
     Clause 153: In some examples, the apparatus includes clause 152, wherein at least some filaments of the plurality of filaments, at the outer layer at the distal section, have an etched surface. 
     Clause 154: In some examples, the apparatus includes clause 152, wherein between about 50 percent and about 100 percent of the plurality of filaments include drawn filled tubes. 
     Clause 155: In some examples, the apparatus includes clause 154, wherein at least some of the drawn filled tubes includes a radiopaque core having a cross-sectional area that is between about 51% and about 70% of the total cross-sectional area. 
     Clause 156: In some examples, the apparatus includes clause 132, further including a pusher having a proximal end and a distal end, wherein the occlusion element is configured to be releasably coupled to the distal end of the pusher at a releasable joint. 
     Clause 157: In some examples, the apparatus includes clause 156, further including a connection tube having a proximal end substantially flush with a proximal end of the occlusion element, a distal end extending within the occlusion element, and a lumen, wherein the distal end of the pusher extends through the lumen of the connection tube and includes a plurality of radially extending protrusions located distal to the distal end of the connection tube, the plurality of radially extending protrusions forming a maximum transverse dimension that is greater than a maximum diameter of the lumen of the connection tube. 
     Clause 158: In some examples, the apparatus includes clause 157, further including an activator configured to modify the plurality of radially extending protrusions such that the distal end of the pusher can be fully removed from the lumen of the connection tube. 
     Clause 159: In some examples, the apparatus includes clause 158, wherein the activator is configured to cause an effect to the radially extending protrusions selected from the list consisting of: melting, detaching, unbending, breaking, ablating, and deforming. 
     Clause 160: In some examples, the apparatus includes clause 132, wherein the waist portion includes a circumferential convexity. 
     Clause 161: In some examples, the apparatus includes clause 160, further including a first circumferential concavity adjacent a first end of the circumferential convexity and a second circumferential concavity adjacent a second end of the circumferential convexity. 
     Aneurysms are often non-spherical in shape and may also or alternatively have mild to severe angulations in relation to the vessel or vessels from which they bulge or protrude. This may make the delivery and employment of one or more aneurysm embolization device to the aneurysm a technical and physical challenge. Systems are presented herein to remedy the difficulties that may occur. 
       FIG. 69  illustrates an occlusion device  660  configured for placement within an aneurysm. The occlusion device  660  comprises a cover  663  having an outer diameter D. In some embodiments, the cover  663  is circular, with substantially the same diameter D at any transverse measurement around the perimeter. In other embodiments, the cover  663  is non-circular, and may comprise an ellipse, an oval, a polygon or other shapes. In the non-circular embodiments, the cover  663  comprises a minimum transverse dimension and a maximum transverse dimension. In the particular case of an ellipse or an oval shape, the cover  663  comprises a major diameter and a minor diameter. The minor diameter or minimum transverse dimension is configured to be larger than a maximum transverse dimension of an opening into the aneurysm (the neck portion). Thus, the cover  663  is configured to completely cover the neck portion, and thus to cause stagnation of blood within the aneurysm, leading to occlusion. The cover  663  is constructed from a mesh (braided) Nitinol (nickel-titanium alloy) tube  665  that is inverted on itself, thus providing an outer facing surface  664  and an inner facing surface  661 . The mesh tube  665  is heat-formed such that cover  663  comprises an expanded portion and a first end  675  and a second end  674  of the tube  665  ( FIG. 2 ) each comprise unexpanded (or partially expanded) portions. A smooth fold  662  extends around the circumference  659  of the cover  663  and represents the transition between the outer facing surface  664  and the inner facing surface  661 . The fold  662  avoids any sharp edge that might risk rupture of an aneurysm wall, or other anatomical damage. The cover  663  includes a concavity  657  arranged around a longitudinal axis  668 . The cover  663  is fabricated as an inverted mesh tube  665  having a simple straight elongate configuration, and is subsequently formed into the shape shown in  FIG. 69 , and heat set into this shape. For example, the inverted mesh tube  665  may be constructed as a single layer mesh tube formed of at least some nickel-titanium alloy filaments, and then inverted on itself. The inverted mesh tube  665  may then be placed into a die or mold comprising one or more pieces, to hold it in the shape of the cover  663 . Then, the cover  663  may be subjected to an elevated temperature and then cooled, to lock in the shape, resulting in a cover  663  having at least some superelastic properties. 
     As formed (e.g., heat-formed), the cover  663  has an expanded configuration (shown in  FIG. 69 ) and a collapsed configuration, shown in  FIG. 71 . The cover  663  comprises two mesh layers, provided by the outer facing surface  664  and the inner facing surface  661 . 
     In some embodiments, the cover  663  may comprise some nickel-titanium alloy filaments and some radiopaque elements, comprising platinum, gold, tantalum, or alloys of any of these or other radiopaque materials. In some embodiments, the filaments may comprise drawn filled tubes (DFT), such as those comprising a nickel-titanium alloy outer wall and a platinum core. The radiopaque material allows the cover  663  to be visible on radiographs or fluoroscopy. The occlusion device  660  may be configured by controlling how much radiopaque material is used, by either the ratio of radiopaque filaments to non-radiopaque filaments, or by the amount of platinum core in the drawn filled tubes. In this manner, the cover  663  can be selectively fabricated to be sufficiently visible, but not over visible, e.g., overly bright, such that other objects are obscured. In some embodiments, whether any of the filaments comprise radiopaque materials or not, a marker band  119  may be attached to the proximal end  672  of the occlusion device  660 , by adhesive or epoxy bonding, or swaging, welding or other mechanical attachment. 
     A pusher  669 , having a distal end  673  and a proximal end  667 , may comprise a wire, a hypo tube, or another elongate structure having column support is detachably coupled at its distal end  673  to the proximal end  672  of the occlusion device  660 . A detachable joint  670  may comprise one of a number of detachment systems, including but not limited to pressurized detachment, electrolytic detachment mechanisms, hydraulic detachment mechanisms, mechanical or interlocking detachment mechanisms, chemical detachment mechanisms, heat-activated detachment systems, or frictional detachment systems. During delivery, the pusher  669  is held on its proximal end  667  by a user and pushed in a forward longitudinal direction  676  ( FIGS. 71-72 ), in order to advance the occlusion device  660  to the distal end  679  of a delivery catheter  677  (e.g., a microcatheter) having a delivery lumen  678 . The delivery catheter  677  may also include a proximal hub  137 , such as a luer connector. 
     In the embodiment of  FIG. 70 , the pusher  669  comprises an outer tube  153  and an inner wire  151  coupled to each other. Conductors (e.g., electrical wires)  147 ,  149  are electrically coupled distally to the inner wire  151  and outer tube  153  (e.g., if a metallic tube), and proximally to first and second circumferential contacts  143 ,  145  which are carried on a hub  141  that is attached to the proximal end  667  of the pusher  669 . The hub  141  has a cavity  671  into which the proximal end  667  of the pusher  669  is inserted and bonded. The hub  141  and its circumferential contacts  143 ,  145  is reversibly couplable to a connector (not shown) of a detachment controller (not shown), such as those known in the art. The detachment of the occlusion device  660  from the pusher  669  may be achieved by use of the detachment controller by any of the detachment systems, including but not limited to pressurized detachment, electrolytic detachment mechanisms, hydraulic detachment mechanisms, mechanical or interlocking detachment mechanisms, chemical detachment mechanisms, heat-activated detachment systems, or frictional detachment systems. 
     Turning to  FIG. 73 , the cover  663  of the occlusion device  660  in its expanded configuration includes a concavity  657  arranged generally around a longitudinal axis  668 . This does not require that the longitudinal axis  668  be a complete axis of symmetry, as the cover may or may be an elliptical shape, or another non-circular shape. The pusher  669  extends from the detachable joint  670  along its own longitudinal axis  135  that is not colinear with the longitudinal axis  668 . A non-zero angle θ is thus formed between the two longitudinal axes  668 ,  135 . The angle θ may be between about 15 degrees and about 120 degrees, or between about 30 degrees and about 120 degrees, or between about 40 degrees and about 100 degrees, or between about 45 degrees and about 90 degrees, or between about 75 degrees and about 90 degrees. This angulation aids in the delivery of the occlusion device  660  to an aneurysm that has an angulated takeoff and/or that is located along a tortuous artery or an artery having a severe bend, as will be shown in  FIGS. 74A-76C . 
     Furthermore, the outer facing surface  664  has a general center point  133  at the longitudinal axis  668 . The center point  133  (and longitudinal axis  668 ) are separated from the detachable joint  670  by a non-zero distance r. Thus, the detachable joint  670  is radially offset from the longitudinal axis  668 . The maximum radius r MAX  of the cover  663  is the largest radius measured from the longitudinal axis  668  to the circumference  131 , for example, at any point on the circumference  131  on a generally circular cover, or at a point along the circumference  131  (or in general, perimeter) that is along a major axis, as in an ellipse. The phrase “radially offset,” when used herein, should be interpreted as meaning at least about 5% radially offset. In some embodiments, the distance r is at least about 10% of the maximum radius r MAX , at least about 25% of the maximum radius r MAX , or at least about 50% of the maximum radius, or at least about 75% of the maximum radius r MAX . The offset (distance r) aids in the delivery of the occlusion device  660  to an aneurysm that has an angulated takeoff and/or that is located along a tortuous artery or an artery having a severe bend, as will be shown in  FIGS. 74A-76C . 
     Although in  FIG. 73  there is both a non-zero angle θ and a non-zero distance r, in other embodiments, there may be a non-zero angle θ but a substantially zero distance r, as in the occlusion device  1114  of  FIG. 78 . In other embodiments, there may be a non-zero distance r and a substantially zero degree angle θ, as in the occlusion device  1109  of  FIG. 77 . 
       FIGS. 74A-76C  illustrate arteries  681 ,  802 ,  902  having sidewall aneurysms  680 ,  800 ,  900 . The approach by catheter (e.g., delivery catheter/microcatheter  685 ) in a sidewall aneurysm is often challenging when placing a single occlusion device. A distal end  686  of the delivery catheter  685  may be supplied preshaped with a particular curve, or may be steam shaped or shaped by other manners by a user, to create a preferred curve, prior to the insertion of the delivery catheter  685  into the patient&#39;s vasculature, such that the delivery angle of occlusion devices  687 ,  692 ,  698  into the aneurysm  680 ,  800 ,  900  allows a delivery along an axis that is substantially or somewhat parallel to a longitudinal axis of the neck  683 ,  806 ,  906  of the aneurysm  680 ,  800 ,  900 , or substantially or somewhat parallel to a longitudinal axis of the sac of the aneurysm  680 ,  800 ,  900  itself. However, the curvature of the artery  681 ,  802 ,  902  or a small diameter of the artery  681 ,  802 ,  902  may make it difficult for a curved tip of a delivery catheter  685  to fit in the artery  681 ,  802 ,  902 , adjacent the neck  683 ,  806 ,  906 . In other cases, the curved tip may not be able to provide sufficient backup support for delivering the implant (occlusion device). Occlusion devices  687 ,  692 ,  698  according to the embodiments disclosed herein ameliorate the efficacy of embolizations performed in these anatomical conditions by allowing the user to choose particular device parameters that match the anatomy. 
     In  FIG. 74A  an occlusion device  687  comprising a cover  688  detachably coupled to a pusher  691  at a detachable joint  1103  is delivered through a delivery catheter  685  to an aneurysm  680  extending from an artery  681 . The aneurysm  680  includes a dome  682  and a neck  683 . The occlusion device  687  is similar to the occlusion device  660 , but has a different angle θ and offset distance r, as seen in  FIG. 74A . The particular occlusion device  687  (e.g., size, specification, model) may be chosen by the attending physician to fit the aneurysm  680 , with the angle θ and offset distance r particularly chosen to aid the delivery through the artery  681  and into the aneurysm  680 , and to optimize the geometry of the system (e.g. delivery catheter  685  and occlusion device  687 ) during detachment. The cover  688  has a concavity  690  and an outer perimeter  1104 , or circumference ( FIG. 74C ). In  FIG. 74B , the cover  688  is detached from the pusher  691  via the detachable joint  1103  in any one of the manners described in relation to the occlusion device  660 . The pusher  691  and the delivery catheter  685  are then removed from the patient, leaving the occlusion device  687  deployed within the aneurysm  680 , as shown in  FIG. 74C . The outer facing surface  689  of the cover  688  is seated against a lower wall portion  708  of the aneurysm  680  sac, against the neck  683  of the aneurysm  680 . The outer perimeter  1104  extends into the sac, at least at some of its portions, and extends in a direction substantially away from the neck  683  of the aneurysm  680 . 
     In  FIG. 75A  an occlusion device  692  comprising a cover  693  detachably coupled to a pusher  696  at a detachable joint  695  is delivered through a delivery catheter  685  to an aneurysm  800  extending from an artery  802 . The aneurysm  800  includes a dome  804  and a neck  806 . The occlusion device  692  is similar to the occlusion device  660 , but has a different angle θ and offset distance r, as seen in  FIG. 75A . The particular occlusion device  692  (e.g., size, specification, model) may be chosen by the attending physician to fit the aneurysm  800 , with the angle θ and offset distance r particularly chosen to aid the delivery through the artery  802  and into the aneurysm  800 , and to optimize the geometry of the system (e.g. delivery catheter  685  and occlusion device  692 ) during detachment. The cover  693  has a concavity  697  and an outer perimeter  1106 , or circumference ( FIG. 75C ). In  FIG. 75B , the cover  693  is detached from the pusher  696  via the detachable joint  695  in any one of the manners described in relation to the occlusion device  660 . The pusher  696  and the delivery catheter  685  are then removed from the patient, leaving the occlusion device  692  deployed within the aneurysm  800 , as shown in  FIG. 75C . The outer facing surface  694  of the cover  693  is seated against a lower wall portion  808  of the aneurysm  800  sac, against the neck  806  of the aneurysm  800 . The outer perimeter  1106  extends into the sac, at least at some of its portions, and extends in a direction substantially away from the neck  806  of the aneurysm  800 . 
     In  FIG. 76A  an occlusion device  698  comprising a cover  699  detachably coupled to a pusher  1101  at a detachable joint  1102  is delivered through a delivery catheter  685  to an aneurysm  900  extending from an artery  902 . The aneurysm  900  includes a dome  904  and a neck  906 . The occlusion device  698  is similar to the occlusion device  660 , but has a different angle θ and offset distance r, as seen in  FIG. 76A . The particular occlusion device  698  (e.g., size, specification, model) may be chosen by the attending physician to fit the aneurysm  900 , with the angle θ and offset distance r particularly chosen to aid the delivery through the artery  902  and into the aneurysm  900 , and to optimize the geometry of the system (e.g. delivery catheter  685  and occlusion device  698 ) during detachment. The cover  699  has a concavity  1100  and an outer perimeter  1108 , or circumference ( FIG. 76C ). In  FIG. 76B , the cover  699  is detached from the pusher  1101  via the detachable joint  1102  in any one of the manners described in relation to the occlusion device  660 . The pusher  1101  and the delivery catheter  685  are then removed from the patient, leaving the occlusion device  698  deployed within the aneurysm  900 , as shown in  FIG. 76C . The outer facing surface  408  of the cover  699  is seated against a lower wall portion  908  of the aneurysm  900  sac, against the neck  906  of the aneurysm  900 . The outer perimeter  1108  extends into the sac, at least at some of its portions, and extends in a direction substantially away from the neck  906  of the aneurysm  900 . 
     As can be seen in  FIGS. 74A-76C , the particular angle θ and/or offset distance r make possible optimized delivery and deployment of the occlusion devices  687 ,  692 ,  698  within the aneurysms  680 ,  800 ,  900 . In  FIGS. 74A and 75A , the delivery catheter  685  is shown having little or no curve formed onto its distal end  686 . However, in  FIG. 76A , the distal end  686  has a curve  163  preformed or physician-formed, to aid the delivery of the occlusion device  698  into the aneurysm  900 . The curve  163  is more or less oriented along the plane of the page, with radius or radii or curvature that are substantially orthogonal to the page (i.e., extend vertically from the page). However, because the occlusion device  698  has a concave shape arrange around a longitudinal axis  418 , and because the occlusion device  698  and pusher  1101  together form a structure that is asymmetric to the longitudinal axis  418 , it may be desirable to selectively control the oriental rotation of the occlusion device  698  in relation to its longitudinal axis  418 , which would thus further control the overall orientation of the occlusion device  698  in relation to the aneurysm  900 . 
     Returning to  FIG. 69 , the cover  663  may be braided such that the braiding, mesh, etc., is arranged somewhat symmetrically around the longitudinal axis  668 . However, it may also be desired in alternative embodiments to asymmetrically form the braiding around the longitudinal axis  668 , such that when the cover  663  is compressed into its collapsed configuration, it actually preferentially favors (via structure and sliding mechanics) forming a more linear structure, oriented more along the longitudinal axis  135  ( FIG. 73 ). Thus, while compressed within the lumen  678  of the delivery catheter  677 , the longitudinal axis  668  and the “pseudo” longitudinal axis  135  (because the cover  663  is now temporarily deformed) are now forced into an angle θ of substantially 90 degrees (in relation to each other). That is, until the cover  663  is delivered from the lumen  678  of the delivery catheter  677 , allowing it to take its expanded configuration, and, via the memory of the braid material, to conform to its true angle θ. The asymmetric braiding may be achieved by using a braiding process or automated braiding machine that varies the braid angle in an oscillating or sinusoidal manner. For example, at a particular clock location around the circumference  659  of the cover  663  (e.g., 6 o&#39;clock) the braid angle may equal a first value X and at another clock location around the circumference  659  of the cover  663  (e.g., 9 o&#39;clock) the braid angle may equal a second value 0.8×. In some embodiments, the second value may be between about 40% and about 95% of the first value, or between about 50% and about 90% of the first value, or between about 60% and about 85% of the first value. 
       FIG. 77  illustrates an occlusion device  1109  comprising a cover  1110  detachably coupled to a pusher  1113  at a detachable joint  1112 . The cover  1110  has an outer perimeter  514 . The longitudinal axis  1111  of the cover  1110  is radially offset from the longitudinal axis  535  of the pusher  1113  by a non-zero distance r. There is substantially a zero angle between the longitudinal axis  1111  of the cover and the longitudinal axis  535  of the pusher  1113 . 
       FIG. 78  illustrates an occlusion device  1114  comprising a cover  1115  detachably coupled to a pusher  652  at a detachable joint  658 . The cover  1115  has an outer perimeter  1116 . The longitudinal axis  1117  of the cover  1115  is angled from the longitudinal axis  635  of the pusher  652  by a non-zero angle θ. There is substantially a zero distance r between the longitudinal axis  1117  of the cover  1115  and the longitudinal axis  635  of the pusher  652 . 
     Though the occlusion devices  660 ,  687 ,  692 ,  698 ,  1109 ,  1114  as described according to embodiments disclosed herein are shown generally having a proximal convexity and a distal concavity, and are configured to predominantly being placed in a lower (near the neck) portion of an aneurysm, any other configuration for an aneurysm occlusion device is also contemplated for use in combination with the attachment/detachment geometries taught in the embodiments disclosed. This includes devices configured to be the only device implanted in the aneurysm, as well as devices configured to be one or a plurality of devices implanted in the aneurysm.  FIGS. 79-84  illustrate six different occlusion systems  770 ,  772 ,  774 ,  776 ,  778 ,  780  being utilized to deliver a braided shell  758  into an aneurysm  750  having a dome  752  and a neck  768 . The braided shell  758  has a longitudinal axis  756  and is configured to fill a majority of the aneurysm  750  or in some cases substantially all of the aneurysm  750  sac. The braided shell  758  is braided or woven from filaments  760 , and has a proximal end  751 , a distal end  753 , and an intermediate portion  782 . The aneurysm  750  has the geometry of a sidewall aneurysm in relation to left extending artery  762  and right extending artery  764 . The aneurysm  750  alternatively has the geometry of a terminal aneurysm in relation to artery  754 . An additional vessel  766  may also be present. It may be desired to avoid the embolization of this vessel  766  in the process of embolizing the aneurysm  750 . 
     In  FIG. 79 , the occlusion system  770  includes a pusher  784  that is detachably coupled to the proximal end  751  of the braided shell  758  at a detachable joint  785 . The pusher  784  extends from the detachable joint  785  at a non-zero angle in relation to the longitudinal axis  756  of the braided shell  758 . The detachable joint  785  is dimensionally offset a non-zero distance from the longitudinal axis  756  of the braided shell  758 . The offset side is the same as the side that the pusher  784  extends. The occlusion system  770  is shown in  FIG. 79  being delivered from the artery  762 , though it may also be delivered from one or more other arteries. 
     In  FIG. 80 , the occlusion system  772  includes a pusher  786  that is detachably coupled to the proximal end  751  of the braided shell  758  at a detachable joint  787 . The pusher  786  extends from the detachable joint  787  at a non-zero angle in relation to the longitudinal axis  756  of the braided shell  758 . The detachable joint  787  is dimensionally offset a non-zero distance from the longitudinal axis  756  of the braided shell  758 , which is located on an opposite side of the longitudinal axis from the side that the pusher  784  extends. The occlusion system  772  is shown in  FIG. 80  being delivered from the artery  762 , though it may also be delivered from one or more other arteries. 
     In  FIG. 81 , the occlusion system  774  includes a pusher  788  that is detachably coupled to the proximal end  751  of the braided shell  758  at a detachable joint  789 . The pusher  788  extends from the detachable joint  789  at a non-zero angle in relation to the longitudinal axis  756  of the braided shell  758 . The detachable joint  789  is generally not offset from the longitudinal axis  756  of the braided shell  758 , but is instead coupled substantially at the longitudinal axis  756 . The occlusion system  774  is shown in  FIG. 81  being delivered from the artery  762 , though it may also be delivered from one or more other arteries. 
     In  FIG. 82 , the occlusion system  776  includes a pusher  790  that is detachably coupled to the proximal end  751  of the braided shell  758  at a detachable joint  791 . The pusher  790  extends from the detachable joint  791  at a substantially zero angle in relation to the longitudinal axis  756  of the braided shell  758 . The detachable joint  791  is dimensionally offset a non-zero distance from the longitudinal axis  756  of the braided shell  758 . The occlusion system  776  is shown in  FIG. 82  being delivered from the artery  754 , though it may also be delivered from one or more other arteries. 
     In  FIG. 83 , the occlusion system  778  includes a pusher  792  that is detachably coupled to the proximal end  751  of the braided shell  758  at a detachable joint  793 . The pusher  792  extends from the detachable joint  793  at a non-zero angle in relation to the longitudinal axis  756  of the braided shell  758 . The detachable joint  793  is dimensionally offset a non-zero distance from the longitudinal axis  756  of the braided shell  758 . The offset side is opposite of the side that the pusher  792  extends. The occlusion system  778  is shown in  FIG. 83  being delivered from the artery  754 , though it may also be delivered from one or more other arteries. 
     In  FIG. 84 , the occlusion system  780  includes a pusher  794  that is detachably coupled to the proximal end  751  of the braided shell  758  at a detachable joint  795 . The pusher  794  extends from the detachable joint  795  at a non-zero angle in relation to the longitudinal axis  756  of the braided shell  758 . The detachable joint  795  is not offset from the longitudinal axis  756  of the braided shell  758 , but is instead coupled substantially at the longitudinal axis  756 . The occlusion system  780  is shown in  FIG. 84  being delivered from the artery  754 , though it may also be delivered from one or more other arteries. 
     As can be seen in  FIGS. 79-84 , the angle θ and/or offset distance r make possible optimized delivery and deployment of the occlusion devices (braided shell  758 ) within the aneurysm  750 . 
       FIGS. 85 and 86  illustrate a delivery catheter  85  comprising a shaft  87  having a proximal end  89 , a distal end  93  having a curve  97 , and a non-circular lumen  99 . A luer hub  91  is bonded to the proximal end  89  of the shaft  87 . In some embodiments, the non-circular lumen  99  may extend through the entirety of the shaft  87 , but in the embodiment of  FIGS. 85 and 86 , the non-circular lumen  99  morphs into a circular lumen  83  ( FIG. 87 ) at the proximal end  89 . In some embodiments, the shaft  87  may be extruded with a circular lumen  83  its entire length, and then a non-circular cross-section mandrel may be placed in the lumen  83  at the distal end  93 , and heat may be applied to reform the lumen  83  at the distal end  93  to have the non-circular lumen  99  shape. In other embodiments, a first tubular portion  22  having a circular lumen  83  may be thermally fused to a second tubular portion  24  having a non-circular lumen  99 . The mandrel may be placed from the proximal end, and have smooth transitions between a circular outer cross-section and a non-circular outer cross-section, in order to form a transition zone  26  comprising a continuously smooth luminal wall surface transition between the circular lumen  83  and the non-circular lumen  99 . The non-circular lumen  99  is illustrated in  FIG. 85  as an ellipse, buy may alternately by an oval, or any type of non-circular cross-sectional shape. For example, a polygonal shape, a dogbone shape, a guitar shape, or a U-shape. Optionally, to further aid visualization on fluoroscopy (e.g., biplane fluoroscopy), a radiopaque stripe  28  may be extruded or otherwise placed on one side of the wall  30  of the shaft  87 . Thus, a physician delivering the delivery catheter  85  is able to better judge the orientation (the clock position of rotation) of the curve  97  in relation to an aneurysm. The non-circular lumen  99  allows an occlusion device whose compressed or constrained profile is substantially oval or elliptical, or otherwise non-circular, to be selectively oriented rotationally, for example, such that it can only be placed at 0°, or placed at 180°, or at another angle of rotation. A marking  95  on the luer hub  91  can be used to aid the insertion of the occlusion device such that it is oriented at a particular one of the 0° or 180° orientation, by serving as a comparative visual aid. In some embodiments, longitudinal stripes may be placed on the shaft  87  near the distal end  93  to allow steam shaping of the curve  97  (if not preshaped), or reshaping of the curve  97 , along a desired plane. In some embodiments, steam shaping can be done by placing a bendable mandrel within the non-circular lumen  99  to further or alternatively aid the shaping or reshaping of the curve  97  along a desired plane. In some embodiments, the bendable mandrel has a similar cross-section shape as the non-circular lumen  99 , such that it substantially fills the non-circular lumen  99 . 
       FIGS. 88 and 89  illustrate a delivery catheter  32  comprising a shaft  34  having a proximal end  36 , a distal end  38  having a curve  40 , and a non-circular lumen  42 . A luer hub  44  is bonded to the proximal end  36  of the shaft  34 . In this particular embodiment, the non-circular lumen  42  extends through the entirety of the shaft  34 . The non-circular lumen  42  is illustrated in  FIG. 88  as a guitar shape having a first, smaller lobe  46  and a second, larger lobe  48  that are joined together by a waist  50 . The guitar shape thus creates a key for allowing only one particular rotational positional of the occlusion device when it exits from the lumen  42  at the distal end  38  of the shaft  34 , and thus, into the aneurysm. In some embodiments, the non-circular lumen  42  may taper down in size near the distal end  38  of the shaft  34 . Thus, the occlusion device is held substantially tightly near the distal end  38  of the shaft  34 , but there is more space through most of the length of the lumen  42 , to minimize axial friction. Any other type of “keyed” shape may alternatively be used for the non-circular lumen  42 . Optionally, to further aid visualization on fluoroscopy (e.g., biplane fluoroscopy), a longitudinal radiopaque stripe  52  may be extruded or otherwise placed on one side of the wall  54  of the shaft  34 . 
     Turning to  FIGS. 91-94 , a loading sheath (or introducer sheath or insertion sheath)  56  is configured to aid in the insertion of an asymmetric occlusion device  58  (or asymmetric occlusion device  58 /pusher  59 /detachable joint  61  system) into the non-circular lumen  60  ( FIG. 94 ) of a delivery catheter  62 . The non-circular lumen  60  may only extend within the shaft  64  of the catheter  62 , or the luer hub  66  itself may also have the non-circular lumen  60  (as illustrated in  FIG. 94 ). A removable funnel  68  has a proximal end  70  attached to a distal end  72  of the loading sheath  56 . The funnel  68  has a proximal inner diameter  74  ( FIG. 93 ) that matches the diameter  76  at the distal end  72  of the loading sheath  56 . The funnel  68  smoothly tapers up to an increased inner diameter  78  at a distal end  80 . In use, the occlusion device  58  may be packaged inside the lumen  82  of the loading sheath  56  or may be packaged extending from the loading sheath  56 . Prior to insertion into the non-circular lumen  60  of the delivery catheter  62 , the occlusion device  58  may be prepared by priming or flushing the lumen  82  ( FIG. 91 ) of the loading sheath  56 . The occlusion device  58  may be examined or rinsed in saline or in saline and heparin, external to the loading sheath  56 , as shown in  FIG. 91 . The user then carefully applies traction on (pulls) the pusher  59  to load the occlusion device  58  into the lumen  82  of the loading sheath  56  in the preferred compressed configuration. For example, with folded portions oriented in the most low-profile manner, or with the preferred distally extending portions configured such that they will exit the lumen  82  first. The inner contours of the funnel  68  optimize the ability to preferentially load the occlusion device  58  into the lumen  82 . For example, the preferential loading may be done in a manner to obtain the smallest possible compressed or collapsed diameter. The loaded occlusion device  58  is shown in  FIG. 92 , fully within the lumen  82  of the loading sheath  56 . As shown in  FIG. 93 , the funnel  68  can then be snapped off, unscrewed from, or otherwise removed from the loading sheath  56 . The funnel  68  can then be removed and discarded. In some embodiments, the funnel  68  may be reattachable to the loading sheath  56  Turning to  FIG. 94 , the distal end  72  of the loading sheath  56  is placed close to the entrance of the non-circular lumen  60  such that, for example, a larger profile lobe  84  of the compressed occlusion device  58  can be matched for entry into the larger lobe  86  of the non-circular lumen  60 , and a smaller profile lobe  88  of the occlusion device  58  can be matched for entry into the smaller lobe  90  of the non-circular lumen  60 . The pusher  59  is then pushed by the user to load the occlusion device  58  in the non-circular lumen  60 , and to advance the occlusion device  58  toward the distal end (not shown) of the delivery catheter  62 . The loading sheath  56  may be peel-away, or may simply be pulled back to a proximal portion of the pusher  59 . The occlusion device  58  can now be reliably delivered to an aneurysm in the chosen orientation. For example, correct-side-up, instead of upside-down. In some embodiments, the loading sheath may have external longitudinal stripes on the tubing to aid the user in applying the desired rotational orientation when inserting the occlusion device  58 . 
     Alternative luminal shapes and occlusion device compressed shapes are shown in  FIGS. 95A-95E . In the embodiment of  FIG. 95A , the distal end  852  of a delivery catheter  850  has a non-circular lumen  854  having a pentagonal shape. An occlusion device  856  in its compressed configuration favors a substantially pentagonal shape that is keyable to the shape of the non-circular lumen  854 . In the embodiment of  FIG. 95B , the distal end  858  of a delivery catheter  860  has a non-circular lumen  862  having a diamond shape. An occlusion device  864  in its compressed configuration favors a substantially diamond shape that is keyable to the shape of the non-circular lumen  862 . In the embodiment of  FIG. 95C , the distal end  866  of a delivery catheter  868  has a non-circular lumen  870  having a U-shape. An occlusion device  872  in its compressed configuration favors a substantially U-shape that is keyable to the shape of the non-circular lumen  870 . In the embodiment of  FIG. 95D , the distal end  874  of a delivery catheter  876  has a non-circular lumen  878  having an oval shape. An occlusion device  880  in its compressed configuration favors a substantially oval shape that is keyable to the shape of the non-circular lumen  878 . In the embodiment of  FIG. 95E , the distal end  882  of a delivery catheter  884  has a non-circular lumen  886  having a guitar shape. An occlusion device  888  in its compressed configuration favors a substantially guitar shape that is keyable to the shape of the non-circular lumen  886 . 
       FIGS. 96A and 97A-97C  illustrate an occlusion device  2040  comprising a mesh cover  2042  including a distal concavity  2044 . A radially offset internal tube  2046  having a lumen  2048  and an outer wall  2050  is secured within the mesh cover  2042 , such that its proximal end  2052  is flush or closely adjacent to a proximal end  2054  of the mesh cover  2042 . A pusher  2056  comprises a wire having a distal end  2058  including a plurality of radially-extending fingers  2060  which extend from the distal end  2058 . The fingers  2060  are configured to be meltable, detachable, unbendable, breakable, ablatable, deformable, or otherwise changeable. Prior to detachment, the radially-extending fingers  2060  create a maximum diameter that is larger than the diameter of the lumen  2048  of the internal tube  2046 , such that traction on the wire of the pusher  2056  causes the fingers  2060  to pull on the distal end of the outer wall  2050  of the internal tube  2046 , and thus the pull the entire occlusion device  2040 . For example, the occlusion device  2040  may be advanced into an aneurysm, and if the user does not believe the fit or configuration of the occlusion device  2040  within the aneurysm is desirable, the user may pull on the pusher  2056  to pull the occlusion device  2040  out of the aneurysm and into the lumen of the delivery catheter. However, then the occlusion device  2040  has been delivered into the aneurysm in an acceptable manner, the user may detach by any detachment manner (to deform, damage, or destroy the fingers  2060 ), via modes including but not limited to pressurized detachment, electrolytic detachment mechanisms, hydraulic detachment mechanisms, mechanical or interlocking detachment mechanisms, chemical detachment mechanisms, heat-activated detachment systems, or frictional detachment systems. In one embodiment, mechanical detachment is achieved by pushing the distal end of the microcatheter against the proximal end  2054  of the mesh cover  2042  while pulling on the pusher  2056 , thus bending the fingers  2060 , and removing the pusher  2056  from the occlusion device  2040 . The internal tube  2046  provides for a smooth proximal end  2054  of the mesh cover  2042 , and thus no remnant wire protruding proximally. Remnant protruding wires could cause thrombosis, which may cause embolic stroke. In some embodiments, the distal end  2058  of the pusher  2056  may taper down to as small as 0.001 inch or 0.002 inch, for example, if the distal end  2058  comprises a stainless steel wire. The internal tube  2046  may comprise a polyimide tube, and may have an internal diameter as small as 0.002 inch to 0.010 inch and an outer diameter of between about 0.003 inch and about 0.014 inch. In some embodiments there may be two fingers  2060 , or three fingers  2060 , or four fingers  2060 , or five fingers  2060 , of six fingers,  2060 , or more. 
     The flush or adjacent relation of the proximal end  2052  of the internal tube  2046  to a proximal end  2054  of the mesh cover  2042  assures that there is no detachment remnant extending substantially proximal to the proximal end  2054  of the mesh cover  2042  (and into the parent artery). Thus, any potentially related thromboembolic events may be avoided, in cases wherein such a remnant would be a risk.  FIG. 96B  illustrates an alternative distal end  2058   b  comprising a ball  2062  having a spherical or globular shape. The detachment may occur at the ball  2062 , or at a portion  2064  of the distal end  2058   b  proximal to the ball  2062 , or at both. The ball  2064  may be attached to the pusher  2056  by epoxy, adhesive, welding, brazing, or soldering, or may be formed from the material of distal end  2058   b  by welding.  FIG. 96C  illustrates an alternative distal end  2058   c  comprising a disk  2066  having a flattened, circular shape. The detachment may occur at the disk  2066 , or at a portion  2068  of the distal end  2058   c  proximal to the disk  2066 , or at both. The disk  2066  may be attached to the pusher  2056  by epoxy, adhesive, welding, brazing, or soldering, or may be formed from the material of distal end  2058   c  by welding.  FIG. 96D  illustrates an alternative distal end  2058   d  comprising a tip  2070  having a frustoconical shape. The detachment may occur at the tip  2070 , or at a portion  2072  of the distal end  2058   d  proximal to the tip  2070 , or at both. The tip  2070  may be attached to the pusher  2056  by epoxy, adhesive, welding, brazing, or soldering, or may be formed from the material of distal end  2058   d  by welding.  FIG. 96E  illustrates an alternative distal end  2058   e  comprising a tip  2076  having a flattened reverse spear shape. The detachment may occur at the tip  2076 , or at a portion  2078  of the distal end  2058   e  proximal to the tip  2076 , or at both. The tip  2076  may be attached to the pusher  2056  by epoxy, adhesive, welding, brazing, or soldering, or may be formed from the material of distal end  2058   e  by welding, or may be a flattened portion of the pusher  2056  wire, e.g., by rolling or pressing. In each of the alternative embodiments, the diameter (or maximum transverse dimension) of the ball  2062 , the disk  2066 , the proximal end  2074  of the tip  2070 , or the distal end  2080  of the tip  2076  are greater than the diameter of the lumen  2048  of the internal tube  2046 , thus allowing the occlusion device  2040  to be detachably locked to the pushed  2056 . Any of the tip configurations displayed in  FIGS. 10A-10E and 96A-96E  may be incorporated into a variety of different occlusion devices, including any of the occlusion devices disclosed herein. 
     The following clauses include examples of apparatus of the disclosure. 
     Clause 201: In one example, a vaso-occlusive system configured for embolizing an aneurysm, the aneurysm having a neck and a sac, includes an elongate pusher configured to be slidably disposed within a delivery catheter, the delivery catheter having a proximal end, a distal end, and a delivery lumen extending therebetween, an implantable vaso-occlusive device coupled to a distal end of the pusher, the vaso-occlusive device configured for implantation in the aneurysm sac and having a collapsed delivery configuration when restrained within the delivery lumen of the delivery catheter, and an expanded, deployed configuration after being delivered out of the delivery lumen of the delivery catheter and into the aneurysm sac, wherein the vaso-occlusive device includes a proximal face configured to seat against a lower wall portion of the sac of the aneurysm against the neck of the aneurysm and a concavity, opposite the proximal face, and having a perimeter extending into the sac and away from the neck of the aneurysm, the concavity arranged around a longitudinal axis, and wherein the vaso-occlusive device is configured to be releasably coupled to the distal end of the pusher at a releasable joint, the distal end of the pusher extending from the releasable joint at an angle formed with the central longitudinal axis of between about 30 degrees and about 120 degrees. 
     Clause 202: In some examples, the system includes clause 201, wherein the pusher extends from the releasable joint at an angle formed with the central longitudinal axis of between about 40 degrees and about 100 degrees. 
     Clause 203: In some examples, the system includes clause 201, wherein the pusher extends from the releasable joint at an angle formed with the central longitudinal axis of between about 45 degrees and about 90 degrees. 
     Clause 204: In some examples, the system includes clause 201, wherein the pusher extends from the releasable joint at an angle formed with the central longitudinal axis of between about 75 degrees and about 90 degrees. 
     Clause 205: In some examples, the system includes any one of clauses 201-204, wherein the releasable joint is coupled to the proximal face of the vaso-occlusive device. 
     Clause 206: In some examples, the system includes clause 205, wherein the releasable joint is coupled at a location on the proximal face of the vaso-occlusive device that is radially offset from the central longitudinal axis. 
     Clause 207: In some examples, the system includes clause 206, wherein the vaso-occlusive device in its expanded, deployed configuration has a maximum radius, and wherein the location on the proximal face is offset at least 50% of the maximum radius. 
     Clause 208: In some examples, the system includes clause 206, wherein the vaso-occlusive device in its expanded, deployed configuration has a maximum radius, and wherein the location on the proximal face is offset at least 75% of the maximum radius. 
     Clause 209: In some examples, the system includes clause 206, wherein the vaso-occlusive device in its expanded, deployed configuration has a maximum radius, and wherein the location on the proximal face is at a radial edge. 
     Clause 210: In another example, a vaso-occlusive system configured for embolizing an aneurysm, the aneurysm having a neck and a sac, includes an elongate pusher configured to be slidably disposed within a delivery catheter, the delivery catheter having a proximal end, a distal end, and a delivery lumen extending therebetween, an implantable vaso-occlusive device coupled to a distal end of the pusher, the vaso-occlusive device configured for implantation in the aneurysm sac and having a collapsed delivery configuration when restrained within the delivery lumen of the delivery catheter, and an expanded, deployed configuration after being delivered out of the delivery lumen of the delivery catheter and into the aneurysm sac, wherein the vaso-occlusive device includes a proximal face configured to seat against a lower wall portion of the sac of the aneurysm against the neck of the aneurysm and a concavity, opposite the proximal face, and having a perimeter extending into the sac and away from the neck of the aneurysm, the concavity arranged around a longitudinal axis, and wherein the vaso-occlusive device is configured to be releasably coupled to the distal end of the pusher at a releasable joint, and wherein the releasable joint is coupled at a location on the proximal face of the vaso-occlusive device that is radially offset from the central longitudinal axis. 
     Clause 211: In some examples, the system includes clause 210, wherein the vaso-occlusive device in its expanded, deployed configuration has a maximum radius, and wherein the location on the proximal face is offset at least 50% of the maximum radius. 
     Clause 212: In some examples, the system includes clause 210, wherein the vaso-occlusive device in its expanded, deployed configuration has a maximum radius, and wherein the location on the proximal face is offset at least 75% of the maximum radius. 
     Clause 213: In some examples, the system includes clause 210, wherein the vaso-occlusive device in its expanded, deployed configuration has a maximum radius, and wherein the location on the proximal face is at a radial edge. 
     Clause 214: In some examples, the system includes any one of clauses 201-213, wherein the vaso-occlusive device includes a cover having a first side and a second side, wherein the proximal face includes the first side of the cover and the concavity includes the second side of the cover. 
     Clause 215: In some examples, the system includes any one of clauses 201-214, wherein the vaso-occlusive device is formed from a mesh material 
     Clause 216: In some examples, the system includes clause 215, wherein the mesh material includes a plurality of filaments. 
     Clause 217: In some examples, the system includes clause 216, wherein the plurality of filaments includes filaments including a nickel-titanium alloy. 
     Clause 218: In some examples, the system includes clause 216, wherein the plurality of filaments includes filaments including a radiopaque material. 
     Clause 219: In some examples, the system includes clause 216, wherein the plurality of filaments includes filaments including drawn filled tubes. 
     Clause 220: In some examples, the system includes any one of clauses 217-219, wherein the plurality of filament includes filaments including platinum. 
     Clause 221: In another example, a vaso-occlusive system configured for embolizing an aneurysm, the aneurysm having a neck and a sac, includes an elongate pusher configured to be slidably disposed within a delivery catheter, the delivery catheter having a proximal end, a distal end, and a delivery lumen extending therebetween, an implantable vaso-occlusive device coupled to a distal end of the pusher, the vaso-occlusive device configured for implantation in the aneurysm sac and having a collapsed delivery configuration when restrained within the delivery lumen of the delivery catheter, and an expanded, deployed configuration after being delivered out of the delivery lumen of the delivery catheter and into the aneurysm sac, wherein the vaso-occlusive device includes a proximal face configured to seat against a lower wall portion of the sac of the aneurysm against the neck of the aneurysm and a concavity, opposite the proximal face, and having a perimeter extending into the sac and away from the neck of the aneurysm, the concavity arranged around a longitudinal axis, and wherein the vaso-occlusive device is configured to be releasably coupled to the distal end of the pusher at a releasable joint, and wherein the releasable joint has a characteristic chosen from the list consisting of: (1) the distal end of the pusher extends from the releasable joint at an angle formed with the central longitudinal axis of between about 30 degrees and about 120 degrees, and (2) the releasable joint is coupled at a location on the proximal face of the vaso-occlusive device that is radially offset from the central longitudinal axis. 
     Clause 222: In another example, a system for embolizing an aneurysm includes an expandable implant configured for placement within an aneurysm, the implant having a collapsed configuration and an expanded configuration, the expanded configuration having an asymmetric shape in relation to a longitudinal axis, and a delivery catheter having a proximal end and a distal end and a lumen extending from the proximal end to the distal end, the lumen having a non-circular cross-section at least at a distal region adjacent the distal end of the delivery catheter, wherein expandable implant in its collapsed configuration is configured to fit into the lumen in the distal region in a keyed manner, such that the expandable implant is deliverable from the lumen at the distal end of the delivery catheter in a particular rotational position in relation to the longitudinal axis. 
     Clause 223: In some examples, the system includes clause 222, further including an elongate pusher having a distal end, the distal end releasably coupled to the expandable implant. 
     Clause 224: In some examples, the system includes either one of clauses 222 or 223, wherein the non-circular cross section of the lumen includes an oval. 
     Clause 225: In some examples, the system includes either one of clauses 222 or 223, wherein the non-circular cross section of the lumen includes an ellipse. 
     Clause 226: In some examples, the system includes either one of clauses 222 or 223, wherein the non-circular cross section of the lumen includes a dogbone shape. 
     Clause 227: In some examples, the system includes either one of clauses 222 or 223, wherein the non-circular cross section of the lumen includes a guitar shape. 
     Clause 228: In some examples, the system includes either one of clauses 222 or 223, wherein the non-circular cross section includes a polygonal shape. 
     Clause 229: In some examples, the system includes either one of clauses 222 or 227, wherein the lumen of the delivery catheter has a circular cross-section at its proximal end. 
     Clause 230: In some examples, the system includes clause 229, wherein the circular cross-section extends from the proximal end of the delivery catheter to a proximal end of the distal region. 
     Clause 231: In some examples, the system includes any one of clauses 222-230, wherein the expandable implant in its collapsed configuration has a first transverse axis in relation to the longitudinal axis and a second transverse axis in relation to the longitudinal axis, the first transverse axis orthogonal to the second transverse axis, wherein a first transverse dimension along the first transverse axis is different from a second transverse dimension along the second transverse axis. 
     Clause 232: In some examples, the system includes any one of clauses 222-231, further including a introducer having a proximal end and a distal end and an introducer lumen extending between the proximal end of the introducer and the distal end of the introducer, the introducer lumen configured to hold the expandable implant in its collapsed configuration while the expandable implant is introduced into the lumen of the delivery catheter at its proximal end. 
     Clause 233: In some examples, the system includes clause 232, wherein the introducer includes an outwardly extending collar adjacent its distal end. 
     Clause 234: In some examples, the system includes clause 233, wherein the collar has a proximal end coupled to the distal end of the introducer and a distal end, wherein the collar has a first inner transverse dimension at its proximal end, the first inner transverse dimension about the same as a transverse dimension of the lumen of the introducer at the distal end of the introducer. 
     Clause 235: In some examples, the system includes clause 234, wherein the collar has a second inner transverse dimension at its distal end, the second inner transverse dimension greater than the first inner transverse dimension. 
     Clause 236: In some examples, the system includes clause 235, wherein there is a gradual increase along the collar between the first inner transverse dimension and the second inner transverse dimension. 
     Clause 237: In some examples, the system includes any one of clauses 233-236, wherein the collar is removable from the introducer. 
     Clause 238: In some examples, the system includes either one of clauses 229 or 230, further including a continuously smooth transition region between the circular cross section and the non-circular cross-section. 
     Clause 239: In another example, a method for inserting an expandable implant includes providing an introducer having a proximal end and a distal end and an introducer lumen extending between the proximal end of the introducer and the distal end of the introducer, the introducer lumen configured to hold an expandable implant in its collapsed configuration while the expandable implant is introduced into the lumen of the delivery catheter at its proximal end, wherein the lumen of the delivery catheter has a non-circular shape, and wherein the expandable implant in its collapsed configuration has a substantially non-circular shape, pushing the expandable implant out of the introducer lumen and into the lumen of the delivery catheter such that the substantially non-circular shape of the expandable implant in its collapsed configuration is oriented in a keyed manner with the non-circular shape of the lumen of the delivery catheter, and advancing the expandable implant such that it is entirely within the lumen of the delivery catheter. 
     Clause 240: In another example, a vaso-occlusive system configured for embolizing an aneurysm, the aneurysm having a neck and a sac, includes an elongate pusher configured to be slidably disposed within a delivery catheter, the delivery catheter having a proximal end, a distal end, and a delivery lumen extending therebetween, an implantable vaso-occlusive device coupled to a distal end of the pusher, the vaso-occlusive device configured for implantation in the aneurysm sac and having a collapsed delivery configuration when restrained within the delivery lumen of the delivery catheter, and an expanded, deployed configuration after being delivered out of the delivery lumen of the delivery catheter and into the aneurysm sac, wherein the vaso-occlusive device includes a proximal end configured to seat against the aneurysm adjacent the neck of the aneurysm, a distal end configured to extend in the sac and away from the neck of the aneurysm, and a central longitudinal axis, and wherein the vaso-occlusive device is configured to be releasably coupled to the distal end of the pusher at a releasable joint, wherein the releasable joint includes either one or both of the configurations in the list consisting of: (1) the distal end of the pusher extends from the releasable joint at an angle formed with the central longitudinal axis of between about 30 degrees and about 120 degrees, and (2) the releasable joint is coupled at a location on the proximal end of the vaso-occlusive device that is radially offset from the central longitudinal axis. 
     Clause 241: In some examples, the system includes clause 240, wherein the distal end of the pusher extends from the releasable joint at an angle formed with the central longitudinal axis of between about 40 degrees and about 100 degrees. 
     Clause 242: In some examples, the system includes clause 240, wherein the distal end of the pusher extends from the releasable joint at an angle formed with the central longitudinal axis of between about 45 degrees and about 90 degrees. 
     Clause 243: In some examples, the system includes clause 240, wherein the distal end of the pusher extends from the releasable joint at an angle formed with the central longitudinal axis of between about 75 degrees and about 90 degrees. 
     Clause 244: In some examples, the system includes clause 240, wherein the releasable joint is directly attached to the proximal end of the vaso-occlusive device. 
     Clause 245: In some examples, the system includes clause 240, wherein the vaso-occlusive device in its expanded, deployed configuration has a maximum radius, and wherein the location on the proximal end of the vaso-occlusive device is radially offset from the central longitudinal axis at least 10% of the maximum radius. 
     Clause 246: In some examples, the system includes clause 240, wherein the vaso-occlusive device in its expanded, deployed configuration has a maximum radius, and wherein the location on the proximal end of the vaso-occlusive device is radially offset from the central longitudinal axis at least 50% of the maximum radius. 
     Clause 247: In some examples, the system includes clause 240, wherein the vaso-occlusive device in its expanded, deployed configuration has a maximum radius, and wherein the location on the proximal end of the vaso-occlusive device is radially offset from the central longitudinal axis at least 75% of the maximum radius. 
     Clause 248: In some examples, the system includes clause 240, wherein the vaso-occlusive device in its expanded, wherein the location on the proximal end of the vaso-occlusive device is at a radial edge of the vaso-occlusive device. 
     Clause 249: In some examples, the system includes clause 240, wherein the vaso-occlusive device includes a cover, and wherein the proximal end of the vaso-occlusive device includes a proximal face of the cover, the cover further including a concavity opposite and distal to the proximal face. 
     Clause 250: In some examples, the system includes clause 249, wherein the concavity is generally arranged around the central longitudinal axis. 
     Clause 251: In some examples, the system includes clause 249, wherein the cover has a generally circular outer shape. 
     Clause 252: In some examples, the system includes clause 240, wherein the vaso-occlusive device is formed from a mesh material 
     Clause 253: In some examples, the system includes clause 252, wherein the mesh material includes a plurality of filaments. 
     Clause 254: In some examples, the system includes clause 253, wherein the plurality of filaments includes filaments including a nickel-titanium alloy. 
     Clause 255: In some examples, the system includes clause 253, wherein the plurality of filaments includes filaments including a radiopaque material. 
     Clause 256: In some examples, the system includes clause 253, wherein the plurality of filaments includes filaments including drawn filled tubes. 
     Clause 257: In some examples, the system includes clause 252, wherein the mesh material includes an inverted mesh tube having an outer layer and an inner layer, the outer layer transitioning to the inner layer at an inversion fold. 
     Clause 258: In some examples, the system includes clause 240, further including a selective orientation catheter having a proximal end, a distal end, and a lumen extending from the proximal end to the distal end, wherein the lumen of the selective orientation catheter includes a non-circular cross-section at least at a distal region adjacent the distal end of the selective orientation catheter, wherein the vaso-occlusive device in its collapsed delivery configuration has a substantially non-circular cross-section configured to fit into at least the distal region of the lumen of the selective orientation catheter in a keyed manner, such that the vaso-occlusive device is deliverable from the lumen of the selective orientation catheter in a particular rotational position. 
     Clause 259: In some examples, the system includes clause 258, wherein the non-circular cross-section of the lumen of the selective orientation catheter includes an oval. 
     Clause 260: In some examples, the system includes clause 258, wherein the non-circular cross-section of the lumen of the selective orientation catheter includes an ellipse. 
     Clause 261: In some examples, the system includes clause 258, wherein the non-circular cross-section of the lumen of the selective orientation catheter includes a shape selected from the list consisting of: a dogbone shape, a guitar shape, and a polygonal shape. 
     Clause 262: In some examples, the system includes clause 258, wherein the lumen of the selective orientation catheter has a circular cross-section located at least at its proximal end. 
     Clause 263: In some examples, the system includes clause 262, wherein the circular cross-section of the lumen of the selective orientation catheter includes a circular cross-section region extending from the proximal end of the selective orientation catheter and distally toward a proximal end of the distal region. 
     Clause 264: In some examples, the system includes clause 263, further including a continuously smooth transition region mating the circular cross-section region and the distal region. 
     Clause 265: In some examples, the system includes clause 258, wherein the vaso-occlusive device in its collapsed delivery configuration has a first transverse axis and a second transverse axis, the first transverse axis orthogonal to the second transverse axis, wherein a first transverse dimension along the first transverse axis is different from a second transverse dimension along the second transverse axis. 
     Clause 266: In some examples, the system includes clause 258, further including a introducer having a proximal end, a distal end, and an introducer lumen extending between the proximal end of the introducer and the distal end of the introducer, the introducer lumen configured to hold the expandable implant in its collapsed configuration while the expandable implant is introduced into the lumen of the delivery catheter at its proximal end, wherein the introducer includes collar adjacent its distal end having an inner transverse dimension that increases from a proximal collar end to a distal collar end, the collar configured to facilitate the transitioning of the vaso-occlusive device from its expanded, deployed configuration to its collapsed delivery configuration when traction is placed on the elongate pusher by a user. 
     Clause 267: In some examples, the system includes clause 266, wherein the collar is removable from the introducer by the user, after the vaso-occlusive device has been placed into its collapsed delivery configuration within the introducer lumen of the introducer. 
     Clause 268: In some examples, the system includes clause 240, further including a connection tube having a proximal end substantially flush with a proximal end of the vaso-occlusive device, a distal end extending within the vaso-occlusive device, and a lumen, wherein the distal end of the pusher extends through the lumen of the connection tube and includes a plurality of radially extending protrusions located distal to the distal end of the connection tube, the plurality of radially extending protrusions forming a maximum transverse dimension that is greater than a maximum diameter of the lumen of the connection tube. 
     Clause 269: In some examples, the system includes clause 258, further including an activator configured to modify the plurality of radially extending protrusions such that the distal end of the pusher can be fully removed from the lumen of the connection tube. 
     The ranges disclosed herein also encompass any and all overlap, sub-ranges, and combinations thereof. Language such as “up to,” “at least,” “greater than,” “less than,” “between,” and the like includes the number recited. Numbers preceded by a term such as “approximately”, “about”, and “substantially” as used herein include the recited numbers (e.g., about 10%=10%), and also represent an amount close to the stated amount that still performs a desired function or achieves a desired result. For example, the terms “approximately”, “about”, and “substantially” may refer to an amount that is within less than 10% of, within less than 5% of, within less than 1% of, within less than 0.1% of, and within less than 0.01% of the stated amount. 
     For purposes of the present disclosure and appended claims, the conjunction “or” is to be construed inclusively (e.g., “an apple or an orange” would be interpreted as “an apple, or an orange, or both”; e.g., “an apple, an orange, or an avocado” would be interpreted as “an apple, or an orange, or an avocado, or any two, or all three”), unless: (i) it is explicitly stated otherwise, e.g., by use of “either . . . or,” “only one of,” or similar language; or (ii) two or more of the listed alternatives are mutually exclusive within the particular context, in which case “or” would encompass only those combinations involving non-mutually-exclusive alternatives. For purposes of the present disclosure and appended claims, the words “comprising,” “including,” “having,” and variants thereof, wherever they appear, shall be construed as open-ended terminology, with the same meaning as if the phrase “at least” were appended after each instance thereof.