Patent CA-2342047-A1 (CA)
Title: Device with field-modifying structure
Inventor: RAGHAVAN RAGHU
IPC: A61B5/055
Filed: 2001-03-20
Abstract: A device, such as a medical device, having a distribution of microcoils may be used within an organism under Magnetic Resonant Imaging visualization. The distribution of microcoils on the device being selected from the group consisting of a) at least one pair of opposed RF receiver microcoils having a space between each microcoil of said pair of microcoils, at least one of the coils of said microcoils having at least one adjacent pair of windings on at least one microcoil in which a diameter of one winding on the at least one microcoil increases in winding diameter with respect to a diameter of an adjacent winding; b) at least one pair of radially opposed microcoils physically associated with the solid body, each microcoil having an outside microcoil diameter of 6mm or less, individual windings of said each microcoil together defining a geometric plane for each microcoil, and the plane of each microcoil being parallel to the plane of another microcoil in the pair of radially opposed microcoils; c) at least one RF receiver, the coils of said microcoils defining a cross-section that lies in a plane oriented at 0 to 80 degrees to the longest axis of the device; d) at least one wound microcoil with at least three windings on the microcoil, each winding having an aspect ratio of greater than one, the aspect ratio of each winding being measured as the ratio of longest to shortest dimension in a cross section situated approximately transverse to the winding axis of the coil windings, said winding axis also being transverse to the longest axis of said device; e) at least one microcoil in which a diameter of one winding on the at least one microcoil increases in winding diameter with respect to a diameter of an adjacent winding; f) diameters of at least three consecutive windings within a microcoils increase in diameter with respect to an adjacent winding while moving along the same direction parallel to an axis of the microcoil; g) an element having at least one RF receiver microcoil, the coils of said microcoils defining a cross-sectional contour having an alignment value of at least 0.75 with the longest axis of the device; h) said device is cylindrical, and in response to radiofrequency transmission, generates a reception field which has an average strength that diminishes by a factor of at least 10 from an area defined by a cylinder of 1.5 cm about a core axis of said cylindrical device to an area defined by a cylinder of 4.0 cm about the core axis of said cylindrical device; i) a solid body having at least one pair of opposed microcoils physically associated with the solid body, each microcoil having an outside microcoil diameter of 6mm or less, collective individual windings of said each microcoil defining a geometric plane, and the plane of each microcoil being parallel to the plane of another microcoil in the pair of opposed microcoils; j) a solid body having at least one pair of opposed microcoils physically associated with the solid body, each microcoil having an outside microcoil diameter of 6mm or less, at least 50 number % of individual windings of said each microcoil intersecting a geometric plane, and the geometric plane of each microcoil being parallel to the plane of another microcoil in the pair of opposed microcoils, and there being at least four windings within each microcoil in said at least one pair of opposed microcoils; k) a solid body having at least one pair of radially opposed microcoils physically associated with the solid body, each microcoil having an outside microcoil diameter of 6mm or less, with at least one pair of opposed microcoils physically associated with the solid body at a distal end, at least 50 number % of individual windings of said each microcoil lying within a geometric plane; 1) a solid body having at least one pair of radially opposed microcoils physically associated with the solid body, each microcoil having an outside microcoil diameter of 6mm or less, all individual windings of said each microcoil intersecting a geometric plane, and the plane of each microcoil being parallel to the plane of another microcoil in the pair of radially opposed microcoils; m) a solid body having at least one microcoil physically associated with the solid body, each microcoil having an outside microcoil diameter of 6mm or less, at least 50 number % of individual windings of said each microcoil intersecting a geometric plane perpendicular to an axis of said microcoil; and n) a solid body having at least one microcoil physically associated with the solid body, each microcoil having an outside microcoil diameter of 6mm or less and a common axis, with at least one microcoil physically associated with the solid body at a distal end, at least 50% of individual windings of said each microcoil intersecting a geometric plane perpendicular to said common axis.