Medical device with magnetic resonance visibility enhancing structure

• US 7,172,624 B2
• Filed: 02/06/2003
• Issued: 02/06/2007
• Est. Priority Date: 02/06/2003
• Status: Expired due to Fees

• Current Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Inventors: Wang, Lixiao, Weber, Jan
• Primary Examiner(s): McDermott; Corrine
• Assistant Examiner(s): Sweet; Thomas
• Application Number:
  US10/359,970
• Publication Number:
  US 20040158310A1
• Time in Patent Office: 1,461 Days
• Field of Search: 623/1.15, 623/1.16, 623/1.34, 623/1.46, 600/414, 600/420
• US Class Current: 623/1.16
• CPC Class Codes: A61B 2090/3954 magnetic, e.g. NMR or MRI
• CPC Class Codes: A61F 2/885 comprising a coil including a plurality of spiral or helical sections with alternate directions around a central axis
• CPC Class Codes: A61F 2/90 characterised by a net-like or mesh-like structure
• CPC Class Codes: A61F 2/91 made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes
• CPC Class Codes: A61F 2/915 with bands having a meander structure, adjacent bands being connected to each other
• CPC Class Codes: A61F 2002/91533 characterised by the phase between adjacent bands
• CPC Class Codes: A61F 2002/9155 Adjacent bands being connected to each other
• CPC Class Codes: A61F 2002/91558 connected peak to peak
• CPC Class Codes: A61F 2250/0032 differing in radiographic density
• CPC Class Codes: A61F 2250/0043 differing in electric properties, e.g. in electrical conductivity, in galvanic properties
• CPC Class Codes: A61F 2250/0045 differing in electromagnetical properties

Abstract

A medical device that inhibits distortion of medical resonance images taken of the device. In particular, various structures are utilized to allow visibility proximate, and inside of, a tubular member, such as a stent. In one embodiment, the stent does not contain electrically conductive loops. In an alternative embodiment, rings in the stent are arranged such that current in one ring portion is opposed by current in another ring portion.

Claims

1. A stent comprising;

a generally tubular structure having a plurality of non conductive coil-shaped structural members;

a radiopaque layer covering the coil shaped structural members, wherein each coil-shaped structural member defines a gap in the radiopaque layer; and

a coating of insulating material applied to the radiopaque layer, wherein the coating of the insulating material is disposed in the gaps of the radiopaque layer to prevent the formation of an electrical loop across the gaps.

2. The stent of claim 1, wherein the insulating material is a polymeric material.

3. The stent of claim 1 wherein the structural members are selected from the group comprising ceramics and polymers.

4. A stent comprising:

a generally tubular structure having a plurality of non conductive coil shaped structural members;

a radiopaque layer applied to the coil shaped structural members, wherein each coil-shaped structural member defines a gap in the radiopaque layer; and

a coating of insulating material applied to the radiopaque layer to prevent the formation of an electrical loop across the gaps,

said radiopaque layer and said insulating material being adapted to allow magnetic changes in a region immediately proximate the generally tubular structure, induced by a magnetic resonance imaging process, to be substantially unobstructed by the generally tubular structure.

5. The stent of claim 4 wherein the generally tubular structure comprises a plurality of generally coaxially arranged ring connected to one another such that current induced in adjacent ring flows in opposite directions in the adjacent ring.

6. The stent of claim 5 wherein the ring structures comprise:

a first ring portion including a first end and a second end spaced apart from the first end;

a second ring portion including a first end and a second end spaced apart from the first end of the second ring portion;

a first connector connecting the first end of the first ring portion and the first end of the second ring portion; and

a second connector connecting the second end of the first ring portion and the second end of the second ring portion, wherein a current flows in a first direction in the first ring portion and in a second direction, opposite the first direction, in the second ring portion.

7. The stent of claim 6 wherein the first ring portion and the second ring portion are positioned substantially parallel to each other.

8. The stent of claim 6 wherein the first and second ring portions are made of a substantially non-ferromagnetic material.

9. The stent of claim 6 wherein the first ring portion and the second ring portion define a gap in an axial direction along an outer periphery of the generally tubular structure.

10. The stent of claim 5, wherein the generally tubular structure comprises:

a plurality of rings, each ring compromising;

a first ring portion disposed about a central axis and including a first end and a second end spaced apart from the first end;

a second ring portion disposed about the central axis and including a first end and a second end spaced apart from the first end of the second ring portion;

a first connector connecting the first end of the first ring portion and the first end of the second ring portion; and

a second connector connecting the second end of the first ring portion and the second end of the second ring portion, wherein the first ring portion and the second ring portion define a gap in an axial direction along an outer periphery of the ring; and

a plurality of connectors connecting the plurality of rings.

11. The stent of claim 10 wherein an induced current flows in a first direction around the central axis in the first ring portion and in a second direction, opposite the first direction, around the central axis in the second ring portion in each ring.

12. The stent of claim 10 wherein at least one of the gaps in the plurality of rings is spaced radially about a circumference of the generally tubular structure with respect to one other gap.

13. The stent of claim 4 wherein the plurality of electrically conductive structural members each have an overall conformation rendering the electrically conductive structural members electrically discontinuous.

14. The stent of claim 13 wherein the structural members comprise:

a plurality of rings having an insulating material disposed thereon and spaced about a central axis of the generally tubular structure, the plurality of rings being spaced apart from each other by the insulating material.

15. The stent of claim 14 wherein the insulating material is a polymeric material.

16. The stent of claim 14 wherein the insulating material is a ceramic material.

17. The stent of claim 14 wherein each of the plurality of rings extend axially from a first end of the stent to a second end of the stent in a spiral conformation.

18. The stent of claim 17 wherein at least two of the rings intersect at an angle at an intersection point, and wherein at the intersection point, the insulating material from one of the at least two rings engages the insulating material from the other of the at least two rings.

19. The stent of claim 4 wherein the insulating material covers the radiopaque layer.

20. The stent of claim 4 wherein the structural members are selected from the group comprising ceramics and polymers.