Patent Description:
Guidewires have been used in the medical field to access passages inside patients. In some cases, it may be desirable for a guidewire to have good torqueability, which allows a torque motion applied about a longitudinal axis of the guidewire at a proximal end of the guidewire to cause a corresponding twisting motion at a distal end of the guidewire.

Also, it may be desirable for a distal segment of a guidewire to retain a certain bent shape during use. This allows the distal segment of the guidewire to access certain passage with specific geometry inside the patient. If the distal segment of the guidewire cannot retain its bent shape during use, then it may not be able to access a target passage.

In addition, it may be desirable for a guidewire to have a soft distal segment. This prevents the guidewire from causing injury to the patient, and also allows the guidewire to elastically flex or bend as it is advanced inside the patient through passages of different shapes.

However, it is difficult for a guidewire to achieve all of the above desirable features. A guidewire may have a soft distal segment, but such guidewire may have poor shape retention ability at the distal segment and poor torqueability. On the other hand, a guidewire may have great shape retention ability at the distal segment and good torqueability. However, such guidewire may have a stiff distal segment. The above desirable features are difficult to accomplish together because a soft distal segment of a guidewire usually cannot achieve good torqueability due to the softness of the material that is used to make the distal segment. Also, the material that is used to make the soft distal guidewire segment may not allow the distal guidewire segment to maintain its shape during use. <CIT> discloses a guidewire having (<NUM>) a flat portion with opposite sides and projections on the opposite sides, and (<NUM>) a coil coupled to the flat portion via the projections.

The aforementioned disadvantages are resolved by means of a guidewire according to the invention as defined in claim <NUM>. Such a guidewire includes: a shaft having a proximal end, a distal end, and a body extending from the proximal end to the distal end; a blunt tip; and a sleeve comprising the blunt tip (<NUM>) or being attached to the blunt tip (<NUM>); wherein the body of the shaft comprises at least a segment that is surrounded by the sleeve, the segment coupled to the blunt tip; and wherein the guidewire further comprises a radiopaque coil surrounding at least a part of the segment, the part of the segment having opposite sides with indentations along each of the opposite sides for allowing the radiopaque coil to be screwed over the part of the segment.

Optionally, the part of the segment comprises a flat portion.

Optionally, the segment comprises a flat portion, and the part of the segment is proximal to the flat portion.

Other and further aspects and features will be evident from reading the following detailed description.

The following description includes reference to non-SI units. These are to be converted to SI units by means of the following factors:.

The drawings illustrate the design and utility of embodiments, in which similar elements are referred to by common reference numerals. These drawings are not necessarily drawn to scale. In order to better appreciate how the above-recited and other advantages and objects are obtained, a more particular description of the embodiments will be rendered, which are illustrated in the accompanying drawings. These drawings depict only exemplary embodiments and are not therefore to be considered limiting in the scope of the claims.

It should be noted that the figures are not drawn to scale and that elements of similar structures or functions are represented by the same reference numerals throughout the figures.

<FIG> illustrates a guidewire <NUM> in accordance with some embodiments. The guidewire <NUM> includes a shaft <NUM> having a proximal end <NUM>, a distal end <NUM>, and a body <NUM> extending from the proximal end <NUM> to the distal end <NUM>. The body <NUM> of the shaft <NUM> comprises a distal segment <NUM> having a plurality of different cross sections along a length of the distal segment <NUM>. At least an outer part <NUM> of the body <NUM> that is proximal to the distal segment <NUM> is made of a material having a shear modulus of at least 13000ksi. By means of non-limiting examples, the material of the outer part <NUM> of the body is Molybdenum Rhenium alloy or Tungsten Rhenium alloy.

In the illustrated embodiments, the shaft <NUM> includes a first layer <NUM>, a second layer <NUM>, and a third layer <NUM>. The third layer <NUM> is outside the second layer <NUM>, and the second layer <NUM> is outside the first layer <NUM>. As shown in the figure, the third layer <NUM> comprises the outer part <NUM> of the body <NUM> that is proximal to the distal segment <NUM>. In some embodiments, the third layer <NUM> of the shaft <NUM> may be made from Molybdenum Rhenium alloy or Tungsten Rhenium alloy. Also, in some embodiments, the first layer <NUM> may be made of Molybdenum Rhenium alloy, Tungsten Rhenium alloy, stainless steel, Nitinol, NeoNickel alloy (e.g., MP35N alloy), or Cobalt-Chromium alloy. The second layer <NUM> may be made from Nitinol, or any of the other materials.

In the illustrated embodiments, a part <NUM> of the first layer <NUM> is distal to a distal end <NUM> of the second layer <NUM>, and a part <NUM> of the second layer <NUM> is distal to a distal end <NUM> of the third layer <NUM>, thereby allowing the part <NUM> of the first layer <NUM> and the part <NUM> of the second layer <NUM> to form at least a portion of the distal segment <NUM> of the body <NUM> of the shaft <NUM>. Such configuration is advantageous because it provides the distal segment <NUM> having a cross sectional dimension that is smaller compared to that of a remaining part of the body <NUM> (that is proximal to the distal segment <NUM>). As a result, the distal segment <NUM> is softer compared to the remaining part of the body <NUM>, and may flex or bend more easily.

In some embodiments, the part <NUM> of the first layer <NUM> may be compressed to form an elongated cross sectional shape for the part <NUM> of the first layer <NUM>. For example, in one implementation, the first layer <NUM> may have a circular cross sectional shape, and the part <NUM> of the first layer <NUM> may be compressed into a planar structure having an elongated cross sectional shape, or any of other non-circular cross sections. This feature is advantageous because it provides a bias in the direction of bending for the part <NUM> of the first layer <NUM>. The compressing of the part <NUM> of the first layer <NUM> may be achieved by stamping the part <NUM> of the first layer <NUM> in some embodiments.

In one specific implementation, both the first and third layers <NUM>, <NUM> are made from Molybdenum Rhenium alloy, and the second layer <NUM> is made from Nitinol that is sandwiched between the two Molybdenum Rhenium alloy layers <NUM>, <NUM>. In another specific implementation, the first layer <NUM> is made from stainless steel or Cobalt-Chromium alloy (e.g., MP35N alloy), the second layer <NUM> is made from Nitinol, and the third layer is made from Molybdenum Rhenium alloy. In either implementation, the Nitinol layer <NUM> provides kink resistance and a softer distal segment <NUM>. The first layer <NUM> is shapeable during use, and provides desirable shape retention capability. Also, because of its relatively high shear modulus, the outer Molybdenum Rhenium alloy layer <NUM> provides a desirable torqueability. Furthermore, because of the axial stiffness of the outer Molybdenum Rhenium alloy layer <NUM>, the guidewire <NUM> also has a desirable pushability.

As shown in <FIG>, in some embodiments, the guidewire <NUM> may also include a sleeve <NUM> disposed around at least a part of the distal segment <NUM> (e.g., the distal end <NUM>) of the shaft <NUM>. As shown in the figure, the sleeve <NUM> has a blunt tip <NUM>. The distal end <NUM> of the shaft <NUM> is coupled to the blunt tip <NUM>. The sleeve <NUM> may be any tubular member, and may be made from any materials, such as metal, polymer, etc. In some embodiments, the sleeve <NUM> may be made from Nitinol. The sleeve <NUM> may have a plurality of slots and/or openings to increase a flexibility of the sleeve <NUM>. By means of non-limiting examples, the sleeve <NUM> may be implemented using slotted hypotube, coiled sleeve, tungsten-loaded polymer sleeve, or a combination of the foregoing.

Referring to <FIG>, in some embodiments, the guidewire <NUM> may also include a marker coil <NUM> disposed inside the sleeve <NUM>. As shown in the figure, one end of the marker coil <NUM> is secured to the tip <NUM>, while a body of the marker coil <NUM> is secured to or is abut against a wall of the sleeve <NUM>. In other embodiments, the coil <NUM> may be coupled to only the tip <NUM>, and not to the wall of the sleeve <NUM> (<FIG>). In other embodiments, the proximal end of the marker coil <NUM> may be secured to the second layer <NUM> (e.g., to the distal end <NUM> of the second layer <NUM>), such as by an adhesive, welding, mechanical connector, fusion, etc. In further embodiments, at least a part of the sleeve <NUM> may be formed by the marker coil <NUM> (<FIG>). As shown in the figure, the marker coil <NUM> has a cross sectional dimension that corresponds with (e.g., is the same as) a cross sectional dimension of the sleeve <NUM>. In some cases, an entirety of the length of the sleeve <NUM> may be made from a coil, such as a marker coil.

In the illustrated embodiments of <FIG>, the distal part <NUM> of the segment <NUM> is malleable. Thus, the distal part <NUM> of the segment <NUM> is bendable to form a bent shape. The distal part <NUM> is made from a material that allows it to retain the bent shape after the distal part <NUM> of the segment <NUM> is bent. In other embodiments, the distal part <NUM> (or the first layer <NUM> comprising the distal part <NUM>) may be made from a material that does not have sufficient shape retention capability. In such cases, the guidewire <NUM> may further include a malleable structure attached to the blunt tip <NUM>. The malleable structure may be inside the sleeve <NUM>. During use, the malleable structure is bendable to form a bent shape and is configured to retain the bent shape after the malleable structure is bent. In some embodiments, the malleable structure may be made from Molybdenum Rhenium alloy or Tungsten Rhenium alloy.

The guidewire <NUM> is advantageous because it provides a desirable torqueability, a desirable pushability, and a desirable shape retention ability, while achieving a desirable softness at the distal segment <NUM>. In particular, the outermost layer <NUM> provides a desirable torqueability due to it being made from a material having a sufficiently high (e.g., of at least 13000ksi) shear modulus. Also, the distal segment <NUM> has a desirable bending stiffness, and the distal part <NUM> also has a desirable bending stiffness and shape retention capability. Accordingly, the guidewire <NUM> has optimal combination of soft distal segment, shapeability, and torqueability.

<FIG> illustrates a member <NUM> for making the guidewire <NUM>. The member <NUM> includes the first layer <NUM>, the second layer <NUM>, and the third layer <NUM>. In some embodiments, a part of the third layer <NUM> may be removed to expose the part <NUM> of the second layer <NUM>. Also, a part of the second layer <NUM> may be removed to expose the part <NUM> of the first layer <NUM>. The above actions will result in the shaft <NUM> having multiple different cross sectional shapes along its length, like that shown in <FIG>1E. In some embodiments, the removing of the part of the third layer <NUM>, and the part of the second layer <NUM>, may be accomplished by grinding, cutting, sanding, or any combination of the foregoing.

In the above embodiments, the shaft <NUM> of the guidewire <NUM> has three layers <NUM>, <NUM>, <NUM>. In other embodiments, the shaft <NUM> of the guidewire <NUM> may have more than three layers, or fewer than three layers (e.g., two layers).

<FIG> illustrates a guidewire <NUM> in accordance with some embodiments. Unlike the guidewire of <FIG>, the guidewire <NUM> of <FIG> has only two layers <NUM>, <NUM>. Refer to <FIG>, the guidewire <NUM> includes a shaft <NUM> having a proximal end <NUM>, a distal end <NUM>, and a body <NUM> extending from the proximal end <NUM> to the distal end <NUM>. The body <NUM> of the shaft <NUM> comprises a distal segment <NUM> having a plurality of different cross sections along a length of the distal segment <NUM>. At least an outer part <NUM> of the body <NUM> that is proximal to the distal segment <NUM> is made of a material having a shear modulus of at least 13000ksi. By means of non-limiting examples, the material of the outer part <NUM> of the body is Molybdenum Rhenium alloy or Tungsten Rhenium alloy.

In the illustrated embodiments, the shaft <NUM> includes a first layer <NUM>, and a second layer <NUM>. The second layer <NUM> is outside the first layer <NUM>. As shown in the figure, the second layer <NUM> comprises the outer part <NUM> of the body <NUM> that is proximal to the distal segment <NUM>. In some embodiments, the second layer <NUM> of the shaft <NUM> may be made from Molybdenum Rhenium alloy or Tungsten Rhenium alloy. Also, in some embodiments, the first layer <NUM> may be made of a material having a shear modulus that is less than the shear modulus of the second layer <NUM>. By means of non-limiting examples, the first layer <NUM> may be made from stainless steel, Nitinol, Cobalt-Chromium alloy (e.g., MP35N alloy), etc..

In the illustrated embodiments, the segment <NUM> of the shaft <NUM> is made from the first layer <NUM>. The segment <NUM> is distal to a distal end <NUM> of the second layer <NUM>. The segment <NUM> of the first layer <NUM> has a first part <NUM>, a second part <NUM>, and a third part <NUM>. The third part <NUM> has a cross sectional dimension that is smaller compared to a cross sectional dimension of the first part <NUM>, and the smaller cross sectional dimension of the third part <NUM> transitions into the larger cross section dimension of the first part <NUM> via the second (intermediate) part <NUM>. Such configuration is advantageous because it provides progressively softer sections in the proximal-to-distal direction. As a result, the distal segment <NUM> is softer compared to the remaining part of the body <NUM>, with the distal part <NUM> providing the softest section, and may flex or bend more easily. In other embodiments, the segment <NUM> may comprise more parts or fewer parts than those described above.

In some embodiments, the third part <NUM> of the segment <NUM> may be compressed to form an elongated cross sectional shape for the part <NUM> of the segment <NUM>. For example, in one implementation, the first layer <NUM> may have a circular cross sectional shape, and the part <NUM> of the first layer <NUM> may be compressed into a planar structure having an elongated cross sectional shape, or any of other non-circular shapes. This feature is advantageous because it provides a bias in the direction of bending for the part <NUM> of the first layer <NUM>. The compressing of the part <NUM> of the first layer <NUM> may be achieved by stamping the part <NUM> of the first layer <NUM> in some embodiments.

In one specific implementation, the second layer <NUM> is made from Molybdenum Rhenium alloy, and the first layer <NUM> is made from Nitinol. The inner Nitinol layer <NUM> provides kink resistance and a soft distal end for the guidewire <NUM>, while the outer layer <NUM> provides a desired pushability and a desired torqueability. In another specific implementation, the second layer <NUM> is made from Molybdenum Rhenium alloy, and the first layer <NUM> is made from stainless steel, or Cobalt-Chromium alloy (e.g., MP35N alloy). The first layer <NUM> provides kink resistance and a softer distal segment <NUM>. The first layer <NUM> may be shapeable during use, and provides desirable shape retention capability (e.g., with or without the aid of a malleable structure). Also, because of its relatively high shear modulus, the outer Molybdenum Rhenium alloy layer <NUM> provides a desirable torqueability. Furthermore, because of the axial stiffness of the outer Molybdenum Rhenium alloy layer <NUM>, the guidewire <NUM> also has a desirable pushability.

In the illustrated embodiments of <FIG>, the distal part <NUM> of the segment <NUM> is malleable. Thus, the distal part <NUM> of the segment <NUM> is bendable to form a bent shape. The distal part <NUM> is made from a material that allows it to retain the bent shape after the distal part <NUM> of the segment <NUM> is bent. In other embodiments, as shown in <FIG>, the distal part <NUM> (or the first layer <NUM> comprising the distal part <NUM>) may be made from a material that does not have sufficient shape retention capability. In such cases, the guidewire <NUM> may further include a malleable structure <NUM> attached to the blunt tip <NUM>. The malleable structure <NUM> may be inside the sleeve <NUM>. During use, the malleable structure <NUM> is bendable to form a bent shape and is configured to retain the bent shape after the malleable structure <NUM> is bent. In some embodiments, the malleable structure <NUM> may be made from Molybdenum Rhenium alloy or Tungsten Rhenium alloy, in order to provide a desirable shape retention ability for the guidewire <NUM>.

Referring to <FIG>, in some embodiments, the guidewire <NUM> may also include a marker coil <NUM> disposed inside the sleeve <NUM>. As shown in the figure, one end of the marker coil <NUM> is secured to the tip <NUM>, while a body of the marker coil <NUM> is secured to or is abut against a wall of the sleeve <NUM>. In other embodiments, the coil <NUM> may be coupled to only the tip <NUM>, and not to the wall of the sleeve <NUM>. In other embodiments, the proximal end of the marker coil <NUM> may be secured to the distal segment <NUM> (e.g., to any location that is proximal to the part <NUM>, such as to the part <NUM>, the part <NUM>, etc.). The securing may be accomplished using an adhesive, welding, mechanical connector, fusion, etc. In further embodiments, at least a part of the sleeve <NUM> may be formed by the marker coil <NUM>. In such cases, the marker coil <NUM> has a cross sectional dimension that corresponds with (e.g., is the same as) a cross sectional dimension of the sleeve <NUM>. In some cases, an entirety of the length of the sleeve <NUM> may be made from a coil, such as a marker coil.

In some embodiments, the guidewire <NUM> may include both the malleable structure <NUM> and the marker coil <NUM> (<FIG>).

<FIG> illustrates a member <NUM> for making a guidewire. The member <NUM> includes the first layer <NUM>, and the second layer <NUM>. In some embodiments, a part of the second layer <NUM> may be removed to expose the first layer <NUM>. Also, parts of the exposed first layer <NUM> may be removed, with more material being removed distally than proximally. The above actions will result in the shaft <NUM> having multiple different cross sectional shapes along its length, like that shown in <FIG>. In some embodiments, the removing of the part of the second layer <NUM>, and the part of the exposed first layer <NUM>, may be accomplished by grinding, cutting, sanding, or any combination of the foregoing.

In further embodiments, the shaft <NUM> of the guidewire <NUM> may have a single layer. <FIG> illustrates a guidewire <NUM> in accordance with some embodiments. Unlike the guidewire of <FIG>, the guidewire <NUM> of <FIG> has only one layer in each of a distal segment and a proximal segment of the shaft <NUM>. Refer to <FIG>, the guidewire <NUM> includes a shaft <NUM> having a proximal end <NUM>, a distal end <NUM>, and a body <NUM> extending from the proximal end <NUM> to the distal end <NUM>. The body <NUM> of the shaft <NUM> comprises a distal segment <NUM> having a plurality of different cross sections along a length of the distal segment <NUM>. At least an outer part <NUM> of the body <NUM> that is proximal to the distal segment <NUM> is made of a material having a shear modulus of at least 13000ksi. By means of non-limiting examples, the material of the outer part <NUM> of the body is Molybdenum Rhenium alloy or Tungsten Rhenium alloy.

In the illustrated embodiments, the shaft <NUM> includes a proximal segment <NUM> made of a first material, and the distal segment <NUM> is made from a second material that is different from the first material. In some embodiments, the proximal segment <NUM> may be made from Molybdenum Rhenium alloy or Tungsten Rhenium alloy. Also, in some embodiments, the distal segment <NUM> may be made from Nitinol, stainless steel, or Cobalt-Chromium alloy (e.g., MP35N alloy).

As shown in the figure, the distal segment <NUM> has a single layer, and includes a first part <NUM>, a second part <NUM>, a third part <NUM>, a fourth part <NUM>, and a fifth part <NUM>. The fifth part <NUM> has a cross sectional dimension that is smaller compared to a cross sectional dimension of the third part <NUM>, and the smaller cross sectional dimension of the fifth part <NUM> transitions into the larger cross section dimension of the third part <NUM> via the fourth (intermediate) part <NUM>. Similarly, the third part <NUM> has a cross sectional dimension that is smaller compared to a cross sectional dimension of the first part <NUM>, and the smaller cross sectional dimension of the third part <NUM> transitions into the larger cross section dimension of the first part <NUM> via the second (intermediate) part <NUM>. Such configuration is advantageous because it provides progressively softer sections in the proximal-to-distal direction. As a result, the distal segment <NUM> is softer compared to the remaining part of the body <NUM>, with the distal part <NUM> providing the softest section, and may flex or bend more easily. In other embodiments, the distal segment <NUM> may comprise more parts or fewer parts than those described above.

The proximal segment <NUM> also has a single layer. The proximal segment <NUM> may be attached to the distal segment <NUM> via an adhesive, weld, mechanical connector, or fusion.

As shown in the figure, an inner part <NUM> of the body <NUM> that is proximal to the segment <NUM> and the outer part <NUM> of the body <NUM> that is proximal to the segment <NUM> are made from the same material (as shown by the shaded cross section). In one implementation, the outer part <NUM> and the inner part <NUM> of the body <NUM> are made from a same piece of raw material (e.g., Molybdenum Rhenium alloy, Tungsten Rhenium alloy, etc.), so that they have an unity configuration.

In some embodiments, the part <NUM> of the segment <NUM> may be compressed to form an elongated cross sectional shape for the part <NUM>. For example, in one implementation, the part <NUM> may have a circular cross sectional shape, and the part <NUM> of the segment <NUM> may be compressed into a planar structure having an elongated cross sectional shape, or any of other non-circular cross sectional shapes. This feature is advantageous because it provides a bias in the direction of bending for the part <NUM>. The compressing of the part <NUM> may be achieved by stamping the part <NUM> in some embodiments.

In the illustrated embodiments, the guidewire <NUM> also includes a sleeve <NUM> disposed around the distal end <NUM> of the shaft <NUM>. As shown in the figure, the sleeve <NUM> has a blunt tip <NUM>. The distal end <NUM> of the shaft <NUM> is coupled to the blunt tip <NUM>. The sleeve <NUM> may be any tubular member, and may be made from any materials, such as metal, polymer, etc. In some embodiments, the sleeve <NUM> may be made from Nitinol. The sleeve <NUM> may have a plurality of slots and/or openings to increase a flexibility of the sleeve <NUM>. By means of non-limiting examples, the sleeve <NUM> may be implemented using slotted hypotube, coiled sleeve, tungsten-loaded polymer sleeve, or a combination of the foregoing.

In one specific implementation, the proximal segment <NUM> is made from Molybdenum Rhenium alloy, and the distal segment <NUM> is made from Nitinol. In another specific implementation, proximal segment <NUM> is made from Molybdenum Rhenium alloy, and the distal segment <NUM> is made from stainless steel, or Cobalt-Chromium alloy (e.g., MP35N alloy). In either implementation, the distal segment <NUM> provides kink resistance and a soft distal end for the guidewire <NUM>, while the proximal segment <NUM> provides a desired pushability and a desired torqueability. The distal segment <NUM> may be shapeable during use, and provides desirable shape retention capability (e.g., with or without the aid of the malleable structure <NUM>). Also, because of its relatively high shear modulus, the Molybdenum Rhenium alloy proximal segment <NUM> provides a desirable torqueability. Furthermore, because of the axial stiffness of the Molybdenum Rhenium alloy segment <NUM>, the guidewire <NUM> also has a desirable pushability.

Referring to <FIG>, in some embodiments, the guidewire <NUM> may also include a marker coil <NUM> disposed inside the sleeve <NUM>. As shown in the figure, one end of the marker coil <NUM> is secured to the tip <NUM>. In other embodiments, the proximal end of the marker coil <NUM> may be secured to distal segment <NUM> (e.g., to any location that is proximal to the part <NUM>, such as to the part <NUM>, the part <NUM>, or the part <NUM>, etc.). In other embodiments, the coil <NUM> may also be coupled to the wall of the sleeve <NUM>. In further embodiments, at least a part of the sleeve <NUM> may be formed by the marker coil <NUM>. In such cases, the marker coil <NUM> has a cross sectional dimension that corresponds with (e.g., is the same as) a cross sectional dimension of the sleeve <NUM>. In some cases, an entirety of the length of the sleeve <NUM> may be made from a coil, such as a marker coil.

In the illustrated embodiments of <FIG>, the distal part <NUM> of the segment <NUM> is malleable. Thus, the distal part <NUM> of the segment <NUM> is bendable to form a bent shape. The distal part <NUM> is made from a material that allows it to retain the bent shape after the distal part <NUM> of the segment <NUM> is bent. In other embodiments, the distal part <NUM> may be made from a material that does not have sufficient shape retention capability. In such cases, the guidewire <NUM> may further include a malleable structure <NUM> attached to the blunt tip <NUM> (<FIG>). The malleable structure <NUM> may be inside the sleeve <NUM>. During use, the malleable structure <NUM> is bendable to form a bent shape and is configured to retain the bent shape after the malleable structure <NUM> is bent. In some embodiments, the malleable structure <NUM> may be made from Molybdenum Rhenium alloy or Tungsten Rhenium alloy, in order to provide a desirable shape retention ability for the guidewire <NUM>.

In further embodiments, the guidewire may include the malleable structure <NUM> without the marker coil <NUM> (<FIG>).

It should be noted that the guidewire <NUM> is not limited to the examples of <FIG>, and that the guidewire <NUM> may have other configurations in other embodiments. In other embodiments, the guidewire <NUM> may include more than two segments. For example, in other embodiments, the guidewire <NUM> may include three or more segments that are connected in series along a longitudinal axis of the guidewire <NUM>. Also, in other embodiments, at least one of the segments may have multiple layers instead of a single layer.

In further embodiments, the proximal segment <NUM> and the distal segment <NUM> of the guidewire <NUM> may be made from a same piece of raw material. <FIG> illustrates a guidewire <NUM> in accordance with some embodiments. The guidewire <NUM> includes a shaft <NUM> having a proximal end <NUM>, a distal end <NUM>, and a body <NUM> extending from the proximal end <NUM> to the distal end <NUM>. The body <NUM> of the shaft <NUM> comprises a distal segment <NUM> having a plurality of different cross sections along a length of the distal segment <NUM>. At least an outer part <NUM> of the body <NUM> that is proximal to the distal segment <NUM> is made of a material having a shear modulus of at least 13000ksi. By means of non-limiting examples, the material of the outer part <NUM> of the body is Molybdenum Rhenium alloy or Tungsten Rhenium alloy.

In the illustrated embodiments, the shaft <NUM> also includes a proximal segment <NUM>, wherein the proximal segment <NUM> and the distal segment <NUM> are made from the same material. In some embodiments, the material of the proximal segment <NUM> and the distal segment <NUM> may be Molybdenum Rhenium alloy or Tungsten Rhenium alloy. As shown by the shaded cross section, as a result of using the same piece of raw material to make the segments <NUM>, <NUM> of the shaft <NUM>, an inner part <NUM> and the outer part <NUM> of the segment <NUM>, and the segment <NUM>, have an unity configuration.

As shown in the figure, the proximal segment <NUM> and the distal segment <NUM> comprise a single layer, and includes a first part <NUM>, a second part <NUM>, a third part <NUM>, a fourth part <NUM>, and a fifth part <NUM>. The fifth part <NUM> has a cross sectional dimension that is smaller compared to a cross sectional dimension of the third part <NUM>, and the smaller cross sectional dimension of the fifth part <NUM> transitions into the larger cross section dimension of the third part <NUM> via the fourth (intermediate) part <NUM>. Similarly, the fifth third <NUM> has a cross sectional dimension that is smaller compared to a cross sectional dimension of the first part <NUM>, and the smaller cross sectional dimension of the third part <NUM> transitions into the larger cross section dimension of the first part <NUM> via the second (intermediate) part <NUM>. Such configuration is advantageous because it provides progressively softer sections in the proximal-to-distal direction. As a result, the distal segment <NUM> is softer compared to the remaining part of the body <NUM>, with the distal part <NUM> providing the softest section, and may flex or bend more easily. In other embodiments, the distal segment <NUM> may comprise more parts or fewer parts than those described above.

In some embodiments, the part <NUM> may be compressed to form an elongated cross sectional shape for the part <NUM>. For example, in one implementation, the part <NUM> may have a circular cross sectional shape, and the part <NUM> may be compressed into a planar structure having an elongated cross sectional shape, or any of other non-circular cross sectional shape. This feature is advantageous because it provides a bias in the direction of bending for the part <NUM>. The compressing of the part <NUM> may be achieved by stamping the part <NUM> in some embodiments.

As shown in the figure, the guidewire <NUM> also includes a marker coil <NUM> disposed inside the sleeve <NUM>. The marker coil <NUM> is coupled to the tip <NUM>. In some embodiments, the marker coil <NUM> may also be coupled to the wall of the sleeve <NUM>. In other embodiments, the proximal end of the marker coil <NUM> may be secured to distal segment <NUM> (e.g., to any location that is proximal to the part <NUM>, such as to the part <NUM>, the part <NUM>, or the part <NUM>, etc.). The securing may be accomplished using an adhesive, welding, mechanical connector, fusion, etc. In other embodiments, the marker coil <NUM> may form at least a part of the sleeve <NUM>, or may form an entirety of the sleeve <NUM>. In further embodiments, the guidewire <NUM> may not include the marker coil <NUM>.

The guidewire <NUM> of <FIG> is advantageous because it provides an optimal combination of shapeability, shape retention capability, and torqueability. Due to the entirety of the shaft <NUM> of the guidewire <NUM> being made from the same material (e.g., a single raw member), and the resulting shaft <NUM> may have a small profile (e.g., smaller than that in the embodiments of <FIG>). Accordingly, the guidewire <NUM> may be used to access smaller blood vessels, such as distal blood vessels in a brain, thereby reaching more aneurysms that cannot be accessed before. The distal part <NUM> provides kink resistance and a soft distal end for the guidewire <NUM>. The distal part <NUM> and/or the part <NUM> may be shapeable during use, and provides desirable shape retention capability (without the aid of a malleable structure). However, in other embodiments, the guidewire <NUM> may optionally further include a malleable structure to enhance the shape retention capability, as similarly discussed. Also, because of its relatively high shear modulus, the shaft <NUM> made from Molybdenum Rhenium alloy or Tungsten Rhenium alloy provides a desirable torqueability. Furthermore, because of the axial stiffness of shaft <NUM> made from Molybdenum Rhenium alloy or Tungsten Rhenium alloy, the guidewire <NUM> also has a desirable pushability.

It should be noted that the materials for making the shaft <NUM> of the guidewire <NUM> should not be limited to the examples described, and that the shaft <NUM> may be made from other materials in other embodiments. For example, in other embodiments, the shaft <NUM> of the guidewire <NUM> may be made from other materials, as long as a desired torqueability is achieved. In other embodiments, the shaft <NUM> may be made from any material having a Young's Modulus (under annealed condition) of at least <NUM> ksi, or more preferably at least <NUM> ksi, or even more preferably at least <NUM> ksi. Also, in other embodiments, the shaft <NUM> may be made from any material having an ultimate tensile strength (under annealed condition) of at least <NUM> ksi, and more preferably at least <NUM> ksi, and even more preferably at least <NUM> ksi. By means of non-limiting examples, specific materials that may be used include, but are not limited to, Mo-<NUM>. 5Re, W-25Re, SS304, etc..

In addition, it should be noted that the shaft <NUM> of the guidewire <NUM> may have different dimensions in different embodiments. For example, in some embodiments, the shaft <NUM> of the guidewire <NUM> may have a total length that is anywhere from <NUM> inches to <NUM> inches, such as a length that is anywhere from <NUM> inches to <NUM> inches. Also, in some embodiments, the distal segment <NUM> may have a length that is <NUM> inches to <NUM> inches, such as a length that is anywhere from <NUM> inches to <NUM> inches, or a length that is anywhere from <NUM> inches to <NUM> inches. Furthermore, in some embodiments, the distal part <NUM> / <NUM> / <NUM> may have a length that is anywhere from <NUM> inch to <NUM> inch, such as a length that is anywhere from <NUM> inch to <NUM> inch. In some embodiments in which the distal part <NUM> / <NUM> / <NUM> is stamped, the stamped distal part may have a portion with a constant width, wherein the portion may have a longitudinal length of at least <NUM> inch, such as at least <NUM> inch. In addition, in some embodiments, the distal segment <NUM> may have a cross sectional dimension (e.g., diameter) that is anywhere from <NUM> to <NUM> and the distal part <NUM> / <NUM> / <NUM> may have a cross sectional dimension (e.g., diameter) that is anywhere from <NUM> to <NUM><NUM>. In other embodiments, the distal segment <NUM> and/or the distal part <NUM> / <NUM> / <NUM> may have dimensions that are different from those mentioned above.

Furthermore, the number of different cross sections along the length of the distal segment <NUM> is not limited to the examples described previously. In other embodiments, the number of different cross sections along the length of the distal segment <NUM> may be more, or fewer, than the ones described herein.

In addition, in one or more embodiments described herein, a part of the segment <NUM> may have a flat portion. For example, the part <NUM> (in the embodiments of <FIG>), the part <NUM> (in the embodiments of <FIG>), or the part <NUM> (in the embodiments of <FIG> or <FIG>), may be stamped to create a flat portion. Also, in some embodiments, the flat portion of the segment <NUM> may include one or more openings extending through a thickness of the flat portion. This feature is advantageous because it may assist the guidewire <NUM> in achieving a soft distal end without compromising other performance, such as shapeability and/or shape retention of the guidewire <NUM>. <FIG> illustrates a guidewire <NUM> that includes a flat portion <NUM> with an opening <NUM>. In the illustrated embodiments, the flat portion <NUM> may be created by stamping a distal end of a shaft, such as the shaft <NUM> described with reference to any of the embodiments of <FIG>. As described, the shaft <NUM> has a proximal end <NUM>, a distal end <NUM>, and a body <NUM> extending from the proximal end <NUM> to the distal end <NUM>. The body <NUM> of the shaft <NUM> comprises a distal segment <NUM> having a plurality of different cross sections along a length of the distal segment <NUM>. In other embodiments, the shaft that includes the flat portion <NUM> may be any elongated member, such as a core wire. The elongated member may have a cross-sectional dimension that is the same along the length of the elongated member, or may have different cross-sectional dimensions along the length of the elongated member.

As shown in <FIG>, the opening <NUM> of the flat portion <NUM> extends through the thickness of the flat portion <NUM>. The flat portion <NUM> has a long side <NUM> that is parallel to a longitudinal axis <NUM> of the flat portion <NUM>. The opening <NUM> is in a form of an elongated slot, and has a long side <NUM> that is parallel to the long side <NUM> of the flat portion <NUM>. The opening <NUM> of the flat portion <NUM> is advantageous because it reduces the cross-sectional characteristic (such as moment of inertia) of the flat portion <NUM>. Because a bending stiffness of the flat portion <NUM> depends on the moment of inertia of the cross-section of the flat portion <NUM>, by reducing the moment of inertia of the cross-section of the flat portion <NUM>, the bending stiffness of the flat portion <NUM> is also reduced accordingly. Thus, the opening <NUM> of the flat portion <NUM> has the benefit of making the flat portion <NUM> more flexible. The dimension of the opening <NUM> may be configured to achieve a desired stiffness for the flat portion <NUM>.

In the illustrated embodiments, the guidewire <NUM> also includes a tapering portion <NUM> that is proximal the flat portion <NUM>. Also, the guidewire <NUM> comprises a cylinder portion <NUM> that is proximal the tapering portion <NUM>. In some embodiments, the cylinder portion <NUM>, the tapering portion <NUM>, and the flat portion <NUM> may be parts of a shaft (such as, parts of the segment <NUM> of the shaft <NUM>).

In some embodiments, the flat portion <NUM> is bendable to form a bent shape and is configured to retain the bent shape after the flat portion <NUM> is bent. In other embodiments, the flat portion <NUM> may be made from a material that allows the flat portion <NUM> to be elastically bendable, so that the flat portion <NUM> can springs back after being bent.

In other embodiments, instead of having a single opening <NUM>, the flat portion <NUM> may include a series of openings <NUM> arranged along the longitudinal axis <NUM> of the flat portion <NUM> (<FIG>). As shown in the figure, each of the openings <NUM> in the series is a rectangular slot extending through the thickness of the flat portion <NUM>. Alternatively, each of the openings <NUM> in the series may be a circular slot extending through the thickness of the flat portion <NUM> (<FIG>). The openings <NUM> may have other shapes in other embodiments. Furthermore, in other embodiments, the shapes and/or the dimensions of openings <NUM> of the flat portion <NUM> may be different. For example, the flat portion <NUM> may have a first opening <NUM> with a first shape, and a second opening <NUM> with a second shape that is different from the first shape.

In the embodiments of <FIG>, the openings <NUM> are arranged in a row along the longitudinal axis <NUM> of the flat portion <NUM>. In other embodiments, as shown in <FIG>, the openings <NUM> may be in multiple rows arranged along the longitudinal axis <NUM>, with the openings <NUM> being in a staggered configuration.

It should be noted that the number of openings <NUM>, the size of the openings <NUM>, the geometry of the openings <NUM>, and the arrangement of the openings <NUM> are not limited to the examples illustrated. In other embodiments, the number of openings <NUM>, the size of the openings <NUM>, the geometry of the openings <NUM>, the arrangement of the openings <NUM>, or any combination of the foregoing, may be selected or optimized to achieve a desired softness and/or shape retention ability for the distal end of the guidewire <NUM>, depending on the particular application or requirements. Also, in some embodiments, a desired shape retention characteristic of the distal end of the guidewire <NUM> may be achieved by configuring a thickness of the flat portion <NUM> of the guidewire <NUM>. For example, the flat portion <NUM> may be made thicker in some embodiments to enhance the shape retention ability of the distal end of the guidewire <NUM>.

In any of the embodiments of <FIG>, the guidewire <NUM> may include other components, such as those similarly described with references to <FIG>. For example, as shown in <FIG>, in other embodiments, the guidewire <NUM> in any of the embodiments of <FIG> may also include a sleeve <NUM> disposed around at least a part of the segment <NUM>. A side view of the flat portion <NUM> with openings <NUM> extending through the thickness of the flat portion <NUM> is also shown. The sleeve <NUM> may be made from any materials, including but not limited to Nitinol. In some embodiments, the sleeve <NUM> may include one or more slots extending partially or completely through a thickness of a wall of the sleeve <NUM>. In one implementation, the sleeve <NUM> may be a slotted Nitinol sleeve. The guidewire <NUM> may also include a blunt tip <NUM> to which the segment <NUM> and/or the sleeve <NUM> is attached. The guidewire <NUM> may further include a coil <NUM> disposed around the segment <NUM>. The coil <NUM> is located between the segment <NUM> (e.g., the flat portion <NUM> of the segment <NUM>) and the sleeve <NUM>. In some embodiments, the coil <NUM> may be made from a radiopaque material so that that coil <NUM> can function as a radiopaque coil. In one implementation, the coil <NUM> may be made from Platinum Tungsten. This is advantageous because the softer radiopaque material of the coil <NUM> may further increase the softness of the distal tip of the guidewire. In other embodiments, the coil <NUM> may be made from other materials.

In addition, in one or more embodiments described herein, the guidewire <NUM> may also include a radiopaque marker coupled to the flat portion <NUM> of the segment <NUM>. For example, the radiopaque marker may be coupled to the opening <NUM> at the flat portion <NUM>. <FIG> illustrates a method of making a guidewire that includes a flat portion, and a radiopaque marker coupled to the flat portion. First, a raw wire <NUM> is provided (<FIG>). In some embodiments, the raw wire <NUM> has a circular cross-section. In other embodiments, the raw wire <NUM> may have other cross-sectional shapes, such as a square shape, an elliptical shape, a hexagon, an octagon, etc. Next, the raw wire <NUM> is grounded, cut, and/or sanded to create a shaft <NUM> having different cross-sectional dimensions along the longitudinal axis of the shaft <NUM> (<FIG>). In other embodiments, the shaft <NUM> with different cross-sectional dimensions along the longitudinal axis of the shaft <NUM> may be created using any of the techniques described with reference to <FIG>, <FIG>, or <FIG>. In further embodiments, the creation of different cross-sectional dimensions along the longitudinal axis of the shaft <NUM> is optional, and the shaft <NUM> may have an uniform cross-sectional dimensions along the longitudinal axis of the shaft <NUM>. Next, a portion of the shaft <NUM> may be stamped to create the flat portion <NUM> (<FIG>). The created flat portion <NUM> has a first major planar surface, and a second major planar surface that is opposite from the first major planar surface. Then, an opening <NUM> extending through the thickness of the flat portion <NUM> may be created. The opening <NUM> may be created by cutting (e.g., laser cutting, mechanical cutting, etc.) or by puncturing the flat portion <NUM> in some embodiments (<FIG> illustrates a side cross-sectional view of the guidewire <NUM>, particularly showing the opening <NUM> extending through the thickness of the flat portion <NUM>. Next, as shown in <FIG>, a radiopaque marker <NUM> may be inserted into the opening <NUM> of the flat portion <NUM>. In the illustrated embodiments, the radiopaque marker <NUM> has a first portion <NUM> abutting a first side of the flat portion <NUM>, and a second portion <NUM> configured (e.g., sized and/or shaped) for placement into the opening <NUM> of the flat portion <NUM>. After the second portion <NUM> of the radiopaque marker <NUM> has been placed into the opening <NUM>, a third portion <NUM> of the radiopaque marker <NUM> extending from the second portion <NUM> is located on the opposite side of the flat portion <NUM>. Next, the third portion <NUM> of the radiopaque marker <NUM> may be stamped to flatten out the third portion <NUM>. The flattened third portion <NUM> abuts the second side of the flat portion <NUM>, thereby anchoring the radiopaque marker <NUM> at the second side of the flat portion (<FIG>). As shown in the figure, the first portion <NUM> of the radiopaque marker <NUM> has a first cross sectional dimension, the second portion <NUM> of the radiopaque marker <NUM> has a second cross sectional dimension, and the third portion <NUM> of the radiopaque marker <NUM> has a third cross sectional dimension; wherein the first cross sectional dimension is larger than the second cross sectional dimension; and wherein the third cross sectional dimension is larger than the second cross sectional dimension. <FIG> illustrates a top / planar view of the flat portion <NUM> of the guidewire <NUM>, particularly showing the radiopaque marker <NUM> being secured to the flat portion <NUM>.

In other embodiments, multiple openings <NUM> may be created at the flat portion <NUM> (like those shown in the examples of <FIG>). In such cases, multiple radiopaque markers <NUM> may be secured to the flat portion <NUM> using the technique described with reference to <FIG>.

In other embodiments, instead of anchoring the radiopaque marker <NUM> against opposite sides of the flat portion <NUM>, other techniques may be utilized to secure the radiopaque marker <NUM> relative to the flat portion <NUM>. <FIG> illustrates another flat portion <NUM> of a segment of a guidewire <NUM>. The flat portion <NUM> may be a stamped core wire, as similarly described. As shown in the figure, the flat portion <NUM> has a first major surface <NUM> and a second major surface <NUM> opposite from the first major surface <NUM>. The flat portion <NUM> comprises a first radiopaque marker <NUM> secured on the first major surface <NUM> of the flat portion <NUM>, and a second radiopaque marker <NUM> secured on the second major surface <NUM> of the flat portion <NUM>. In other embodiments, the second radiopaque marker <NUM> is optional, and the guidewire <NUM> may not include the second radiopaque marker <NUM>.

As shown in <FIG>, each of the radiopaque marker <NUM> and the radiopaque marker <NUM> is a planar marker having a width that is the same as a width of the flat portion <NUM>. In other embodiments, the radiopaque marker <NUM> and/or the radiopaque marker <NUM> may have a width that is less than the width of the flat portion <NUM>. In further embodiments, the radiopaque marker <NUM> and/or the radiopaque marker <NUM> may have a width that is longer than the width of the flat portion <NUM>.

Various techniques may be employed to secure the marker <NUM> and/or the marker <NUM> onto the flat portion <NUM>. For example, the marker <NUM> and/or the marker <NUM> may be plated onto the flat portion <NUM> in some embodiments. In other embodiments, the marker <NUM> and/or the marker <NUM> may be secured onto the flat portion <NUM> via adhesive. In further embodiments, the marker <NUM> and/or the marker <NUM> may be applied onto the flat portion <NUM> through material-deposition techniques. For example, the marker <NUM> and/or the marker <NUM> may be achieved by depositing (e.g., electroplating) radiopaque material onto the surface of the flat portion <NUM>. The radiopaque material may be Au, Pt, or other materials. In other embodiments, the flat portion <NUM> may be dipped into a solution of radiopaque material, which then hardens to form a radiopaque marker circumferentially disposed around the flat portion <NUM>. In such cases, the marker <NUM> and the marker <NUM> on opposite sides of the flat portion <NUM> are parts of the circumferential radiopaque marker surrounding the flat portion <NUM>. The marker <NUM> and/or the marker <NUM> is advantageous because, besides being radiopaque for imaging purpose, they also provide shape retention property for the flat portion <NUM>. Accordingly, this feature may eliminate the need to provide a separate bendable structure (that has shape retention characteristic) between the shaft of the guidewire and an outer sleeve of the guidewire.

In other embodiments, instead of having only one radiopaque marker on one side of the flat portion <NUM> of the guidewire <NUM>, the flat portion <NUM> may have first multiple radiopaque markers <NUM> secured on the first major surface <NUM> of the flat portion <NUM> (<FIG>). The first multiple radiopaque markers <NUM> are arranged in a row along a longitudinal axis of the flat portion <NUM>. Each of the radiopaque markers <NUM> are spaced apart from each other. As shown in the figure, the guidewire <NUM> also includes second multiple radiopaque markers <NUM> secured on the second major surface <NUM> of the flat portion <NUM>. The second multiple radiopaque markers <NUM> are arranged in a row along a longitudinal axis of the flat portion <NUM>. Each of the radiopaque markers <NUM> are spaced apart from each other. In other embodiments, the second multiple radiopaque markers <NUM> on the second major surface <NUM> of the flat portion <NUM> is optional, and the guidewire <NUM> may not include the second multiple radiopaque markers <NUM>. Various techniques may be employed to secure the markers <NUM> and/or the markers <NUM> onto the flat portion <NUM>. For example, the markers <NUM> and/or the markers <NUM> may be plated onto the flat portion <NUM> in some embodiments. In other embodiments, the markers <NUM> and/or the markers <NUM> may be secured onto the flat portion <NUM> via adhesive. In further embodiments, the markers <NUM> and/or the markers <NUM> may be applied onto the flat portion <NUM> through material-deposition techniques. For example, the markers <NUM> and/or the markers <NUM> may be achieved by selectively depositing radiopaque material by photolithography or other process onto the surfaces of the flat portion <NUM>. As shown in <FIG>, the markers <NUM> and the markers <NUM> are in the form of radiopaque strips. The markers <NUM> and/or the markers <NUM> are advantageous because, besides being radiopaque for imaging purpose, they also serve as stress concentrators and may help in shape retention for the flat portion <NUM>. In other embodiments, the markers <NUM> and/or the markers <NUM> may not be in the form of strips, and other patterns of the markers <NUM>/<NUM> may be used.

In the above embodiments, the flat portion <NUM> is described as having one or more openings for reducing a stiffness of the flat portion <NUM>. In other embodiments, other techniques may be employed to reduce a stiffness of the flat portion <NUM>. For example, in other embodiments, the flat portion <NUM> may include one or more grooves <NUM> at an exterior surface of the flat portion <NUM> (<FIG>). The grooves <NUM> may be implemented as patterned grooves in some embodiments. The groove(s) <NUM> reduces the cross-sectional dimension of the flat portion <NUM>, thereby reducing a stiffness (e.g., bending stiffness) of the flat portion <NUM>. In other embodiments, the flat portion <NUM> may include both groove(s) <NUM> and opening(s), like the opening(s) <NUM> described with reference to <FIG>, to achieve a desired stiffness for the flat portion <NUM>. In further embodiments, the guidewire <NUM> of <FIG> may also include one or more markers secured to the flat portion <NUM>.

In addition, in one or more embodiments described herein, instead of having just one flat portion <NUM>, the segment <NUM> of the guidewire <NUM> may include multiple flat portions <NUM> (<FIG>). In some embodiments, the flat portions <NUM> may be created by stamping multiple parts of a core wire that are spaced apart from each other. As a result, each flat portion <NUM> may have a flat or planar configuration, and adjacent flat portions <NUM> are connected to each other via a cylindrical portion of the core wire. In other words, a part of the core wire between adjacent flat portions <NUM> functions as a connecting portion that connects the adjacent flat portions <NUM>. Since the connecting portion and the adjacent flat portions are all made from the same core wire, they have an unity configuration. The flat portions <NUM> may have the same thickness in some embodiments. In other embodiments, the flat portions <NUM> may have different respective thicknesses. The number of flat portions <NUM>, the thicknesses of the flat portions <NUM>, the spacing between the flat portions <NUM>, or any combination of the foregoing, may be selected or optimized to achieve a desired softness and/or shape retention ability for the distal end of the guidewire <NUM>. In some embodiments, the guidewire <NUM> of <FIG> may also include one or more markers secured to one or each of the flat portions <NUM>.

Furthermore, it should be noted that the marker <NUM> described is not limited to having a planar configuration, and that the manner in which the marker <NUM> is secured to the shaft is not limited to the examples described. In other embodiments, the marker <NUM> may have different shapes, and/or the marker <NUM> may be secured to the shaft in other manners. According to the invention, as shown in <FIG>, the marker <NUM> of the guidewire <NUM> is a radiopaque coil <NUM> surrounding at least a part of a segment <NUM> of a shaft of the guidewire <NUM>. The part of the segment <NUM> has opposite sides <NUM>, <NUM> with indentations <NUM> along each of the opposite sides for allowing the radiopaque coil <NUM> to be screwed over the part of the segment <NUM>. In some embodiments, the part of the segment <NUM> surrounded by the radiopaque coil <NUM> may be a flat portion (e.g., the flat portion <NUM> described herein). In such cases, the indentations <NUM> may be grooves extending through the thickness of the flat portion <NUM>. The indentations <NUM> may be implemented as cutouts in some embodiments. In other embodiments, the part of the segment <NUM> surrounded by the radiopaque coil <NUM> may be another part of the segment <NUM> that is proximal to the flat portion <NUM>. In further embodiments, the segment <NUM> surrounded by the radiopaque coil <NUM> may not be any flat portion. Instead, the segment <NUM> surrounded by the radiopaque coil <NUM> may be an un-flattened portion of a core wire or shaft. The technique shown in <FIG> for attaching the radiopaque coil <NUM> to the segment <NUM> is advantageous because it provides mechanical interaction between the segment <NUM> and the radiopaque coil <NUM>, and it also save space inside an outer distal sleeve of the guidewire <NUM>.

In any of the embodiments of <FIG>, the guidewire <NUM> may include other components, such as those similarly discussed with references to <FIG>. For example, as similarly discussed with reference to <FIG>, in other embodiments, the guidewire <NUM> in any of the embodiments of <FIG> may also include a sleeve <NUM> disposed around at least a part of the segment <NUM>. The sleeve <NUM> may be made from any materials, including but not limited to Nitinol. In some embodiments, the sleeve <NUM> may include one or more slots extending partially or completely through a thickness of a wall of the sleeve <NUM>. In one implementation, the sleeve <NUM> may be a slotted Nitinol sleeve. The guidewire <NUM> may also include a blunt tip <NUM> to which the segment <NUM> and/or the sleeve <NUM> is attached. The guidewire <NUM> may further include a coil <NUM> disposed around at least a part of the segment <NUM>. The coil <NUM> is located between the segment <NUM> (e.g., the flat portion <NUM> of the segment <NUM>) and the sleeve <NUM>. In some embodiments, the coil <NUM> may be made from a radiopaque material so that that coil <NUM> can function as a radiopaque coil. In one implementation, the coil <NUM> may be made from Platinum Tungsten. This is advantageous because the softer radiopaque material of the coil <NUM> may further increase the softness of the distal tip of the guidewire. In other embodiments, the coil <NUM> may be made from other materials.

Also, in any of the embodiments described herein, the guidewire <NUM> may be provided as a part of a medical device. For example, a medical device may include a catheter, and the guidewire <NUM>, wherein the catheter includes a lumen for accommodating the guidewire <NUM>. By means of non-limiting examples, the medical device may be a microcatheter, a balloon catheter, a stent delivery catheter, a catheter for removing blockage in a vessel, a delivery catheter for the guidewire <NUM>, etc..

In one method of use of the guidewire <NUM>, a doctor first bends the distal segment of the guidewire <NUM> into a desired shape, depending on the geometry of the anatomy that the guidewire <NUM> will access. For example, the distal segment of the guidewire <NUM> may be bent to have a L shape, a C shape, a U shape, a S shape, a shape with two or more curves in different planes, etc. The guidewire <NUM> is then placed in a delivery catheter. Then, an incision is made at a skin of a patient. The delivery catheter with the guidewire <NUM> therein is inserted through the incision, and into a blood vessel in the patient. The delivery catheter and the guidewire <NUM> may be advanced distally until the distal end of the guidewire <NUM> and/or the delivery catheter reaches a target site. The target site may be anywhere in the patient's body, such as a blood vessel in a limb, in a torso, in a neck, in a head, etc. The delivery catheter houses the guidewire <NUM> as the delivery catheter is advanced distally. When the delivery catheter reaches a location in the patient that requires the bent shape of the distal segment of the guidewire <NUM> to access, at least a part of the distal segment may be deployed out of the delivery catheter to let the distal segment assumes its bent shape. The bent shape of the distal segment of the guidewire <NUM> steers the guidewire <NUM> into a desired direction, thereby allowing the guidewire <NUM> and the delivery catheter to be advanced distally into a desired passage. The guidewire <NUM> described herein is advantageous because it allows a bent shape of the distal segment of the guidewire <NUM> to be retained, so that the bent shape will not return back to the pre-bent configuration even after the distal segment has traversed different paths in a vessel with different curvatures (or even after the bent distal segment has been placed in a tube, such as a delivery tube). The guidewire <NUM> is also advantageous because it allows the doctor to effectively torque the guidewire <NUM> due to the enhanced torqueability of the guidewire <NUM>, and allows the doctor to push the guidewire <NUM> distally inside the patient without kinking.

Claim 1:
A guidewire (<NUM>) comprising:
a shaft (<NUM>) having a proximal end (<NUM>), a distal end (<NUM>), and a body (<NUM>) extending from the proximal end (<NUM>) to the distal end (<NUM>);
a blunt tip (<NUM>); and
a sleeve (<NUM>) comprising the blunt tip (<NUM>) or being attached to the blunt tip (<NUM>);
wherein the body (<NUM>) of the shaft (<NUM>) comprises a segment (<NUM>) that is surrounded by the sleeve (<NUM>) and coupled to the blunt tip (<NUM>); and
wherein the guidewire (<NUM>) further comprises a radiopaque coil (<NUM>) surrounding at least a part of the segment (<NUM>);
characterized in that the part of the segment (<NUM>) comprises opposite sides (<NUM>, <NUM>) with indentations (<NUM>) along each of the opposite sides (<NUM>, <NUM>) for allowing the radiopaque coil (<NUM>) to be screwed over the part of the segment (<NUM>).