MR COMPATIBLE PUNCTURE CATHETER

Abstract

An MR compatible injection catheter is provided. The MR compatible injection catheter includes an inner shaft; an outer shaft circumferentially surrounding the inner shaft; and a means for actively tracking the catheter in a patient within a MRI. The means for actively tracking the catheter includes two or more tracking coils in the outer shaft. The inner shaft is configured to move relative to the outer shaft and includes an inner tube circumferentially surrounded by an outer tube.

Claims

1. An MR compatible injection catheter comprising: an inner shaft; an outer shaft circumferentially surrounding said inner shaft; and a means for actively tracking the catheter in a patient within a MRI.

2. The MR compatible injection catheter of claim 1 wherein said means for actively tracking the catheter in a patient within a MRI comprises at least one tracking coil.

3. The MR compatible injection catheter of claim 1 wherein said means for actively tracking the catheter in a patient within a MRI comprises two or more tracking coils.

4. The MR compatible injection catheter of claim 3 wherein spacing between the two or more tracking coils is configured to vary with the position of the injection needle or cannula.

5. The MR compatible injection catheter of claim 4 wherein the spacing between the two or more tracking coils is configured to determine the location of the puncture tip.

6. The MR compatible injection catheter of claim 1 further comprising one or more electrodes configured to perform one or more electrophysiology measurements.

7. The MR compatible injection catheter of claim 1 wherein the inner shaft is configured to move relative to the outer shaft.

8. The MR compatible injection catheter of claim 1 wherein the inner shaft comprises an inner tube circumferentially surrounded by an outer tube.

9. The MR compatible injection catheter of claim 8 wherein the outer tube includes a spirally-cut deflectable portion.

10. The MR compatible injection catheter of claim 8 wherein said spirally-cut deflectable portion comprises a stiff material.

11. The MR compatible injection catheter of claim 8 wherein said inner tube comprises a flexible material.

12. The MR compatible injection catheter of claim 11 wherein said flexible material is selected from grilamid, polyimide, and PEBAX.

13. The MR compatible catheter of claim 10 wherein said stiff material is selected from fiber reinforced epoxy, ceramic, and liquid crystal polymer.

14. The MR compatible injection catheter of claim 8 wherein a tip of said outer tube is beveled to from a sharpened, puncture tip.

15. The MR compatible injection catheter of claim 7 wherein a distal end of the inner shaft is operably coupled to a cannula section having a sharpened tip.

16. The MR compatible injection catheter of claim 7 wherein the inner shaft includes a puncture tip operably coupled thereto.

17. The MR compatible injection catheter of claim 16 wherein said puncture tip is bonded to said inner shaft.

18. The MR compatible catheter of claim 17 wherein said puncture tip includes a tracking coil.

19. The MR compatible catheter of claim 18 wherein the puncture tip includes a cannula section having a sharpened tip.

20. The MR compatible catheter of claim 19 wherein the cannula is constructed from a material selected from metal, ceramic, PEEK, and fiber-reinforced epoxy.

21. The MR compatible catheter of claim 1 wherein the inner shaft is fixed relative to the outer shaft.

22. The MR compatible catheter of claim 21 wherein the inner shaft includes a puncture tip operably coupled thereto.

23. The MR compatible catheter of claim 22 further comprising a cannula cover slidable between a first extended position and a second retracted position.

24. The MR compatible catheter of claim 23 wherein said cannula cover is biased in the first extended position by biasing means.

25. The MR compatible catheter of claim 24 wherein said biasing means comprises a compression spring.

26. The MR compatible catheter of claim 23 further comprising a pull wire operably coupled to the cannula cover and configured to cause said cannula to slide the second retracted position.

27. The MR compatible catheter of claim 22 wherein the means for actively tracking the catheter comprises two or more tracking coils in the outer shaft.

28. The MR compatible catheter of claim 7 wherein the means for actively tracking the catheter comprises two or more tracking coils in the outer shaft.

29. The MR compatible catheter of claim 28 wherein the inner shaft comprises a polymer extrusion and the tip is coupled to a cannula section having a sharpened tip.

30. The MR compatible catheter of claim 27 wherein said polymer comprises Grilamid, PEEK or polyimide.

31. The MR compatible catheter of claim 29 wherein said cannula is constructed of metal.

32. The MR compatible catheter of claim 31 wherein said metal is Elgiloy, Nitinol, MP35N, Titanium, Stainless Steel, or Tungsten.

33. The MR compatible catheter of claim 29 wherein said cannula is constructed of a non-metallic material such as ceramic or fiber-reinforced epoxy.

34. The MR compatible catheter of claim 8 wherein the inner tube includes a spirally-cut deflectable portion.

35. The MR compatible injection catheter of claim 34 wherein said spirally-cut deflectable portion comprises a stiff material.

36. The MR compatible injection catheter of claim 34 wherein said stiff material is selected from fiber reinforced epoxy, ceramic, and liquid crystal polymer.

37. The MR compatible injection catheter of claim 34 wherein said outer tube comprises a flexible material.

38. The MR compatible injection catheter of claim 37 wherein said flexible material is selected from grilamid, polyimide, and PEBAX.

39. The MR compatible injection catheter of claim 34 wherein a tip of said inner tube is beveled to from a sharpened, puncture tip.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:

[0033] FIG. 1 is a perspective view of the distal section of one aspect of the injection catheter in accordance with the invention.

[0034] FIG. 2A is a perspective view of the puncture tip of the injection catheter of FIG. 1 in the retracted position.

[0035] FIG. 2B is a perspective view of the puncture tip of the injection catheter of FIG. 1 in the extended position.

[0036] FIG. 3 is a perspective view of another aspect of the puncture catheter in accordance with the invention with the puncture tip in the extended position.

[0037] FIG. 4 is a perspective view of another aspect of the invention showing the distal tracking coil and the proximal tracking coil located in fixed positions on the outer shaft.

[0038] FIG. 5 is a side cutaway view of the distal section of the inner shaft showing the inner tube and outer tube.

[0039] FIG. 6 is a perspective view of the distal section of the inner shaft showing the spiral cut region of the outer tube.

[0040] FIG. 7 is a perspective view of the injection catheter in accordance with the invention showing the cannula cover concealing the sharpened puncture tip and the cannula cover being held in the distal position by biasing means.

[0041] FIG. 8 is a perspective view of the injection catheter in accordance with the invention depicting that when tension is placed on the pull wire, the biasing means compress, the cannula cover slides proximally, and the sharpened puncture tip is exposed.

[0042] FIG. 9A is a solid perspective view of the sliding cannula cover in the extended position.

[0043] FIG. 9B is a solid perspective view of the sliding cannula cover in the retracted position with the puncture tip exposed.

DETAILED DESCRIPTION OF THE INVENTION

[0044] Referring now to the figures, FIG. 1 shows the distal end 100 of a first aspect of the invention. The injection catheter includes an inner shaft 101 that slides within an outer shaft 102. The inner shaft 101 is a long hollow tube that may consist of a braided catheter construction or a simple polymer extrusion. A puncture tip 103 is operably connected to the distal tip of the inner shaft 101. The puncture tip 103 has a small, short cannula 104 fixedly attached on its distal surface. The cannula extends distally from the puncture tip and is a hollow tube that has a sharpened tip 105. The cannula is similar in shape to the distal tip section of a traditional transseptal needle. The connection between the puncture tip 103 and the inner shaft 101 is such that the lumen of the cannula is continuous with the lumen of the inner shaft. The inner diameter of the cannula lumen is preferably smaller than the inner diameter of the inner shaft lumen, but they could be the same size, or the lumen of the inner shaft could be smaller than the lumen of the cannula. The cannula 104 could be constructed of metallic materials such as aluminum, inconel, nitinol, gold, etc. or of non-metallic materials such as PEEK, ceramic, zirconia, delrin, epoxy, etc. The puncture tip 103 also contains a tracking coil 106 and an O-ring 107. A second tracking coil 108 is located on the outer shaft. The injection catheter is made deflectable by locating one or more pull wires in the wall of either or both of the inner shaft or the outer shaft. Utilizing a braided catheter shaft construction for one or both of the inner and outer shafts would mean that deflectable regions could be created by placing a lower durometer or softer material in the distal section of the shafts. The one or more pull wires would be connected in the control handle to a mechanism that would allow the clinician to deflect the distal tip of the puncture catheter. This mechanism could be a slide button, rotation knob, etc.

[0045] FIG. 2A shows the distal section of the injection catheter with the puncture tip 203 retracted. FIG. 2B shows the puncture tip 203 extended. In the retracted position, the tracking coil 206 on the puncture tip 203 is a fixed distance from the tracking coil 208 on the outer shaft 202. As the puncture tip 203 is extended, the distance between the tracking coil 203 on the puncture tip 203 and the tracking coil 208 on the outer shaft 202 increase by the distance the tip is extended. The distance between the tracking coils 206 and 208 provides information on the position of the puncture tip and location of the tip of the cannula 204. This information can be used to determine the precise location of the puncture tip and the degree to which it is extended. The position of the puncture tip can then be displayed during active tracking of the catheter.

[0046] FIG. 3 shows an alternative aspect of the injection catheter. In this aspect, both tracking coils 306 and 308 are located on the outer shaft 302 and remain fixed in place on the outer shaft 302. This aspect removes the requirement for a puncture tip. This configuration allows the cannula 304 to be directly bonded to the inner shaft 301. This aspect of the injection catheter does not allow for precise determination of the cannula location as it is extended from the catheter. The advantage is a simplified manufacturing process and a reduction in the number of moving components within the catheter.

[0047] FIG. 4 shows a third aspect of the injection catheter 400 with the inner shaft 401 constructed in a different manner than the previous aspects. In this aspect, puncture catheter 400 has both the distal tracking coil 406 and the proximal tracking coil 408 located in fixed positions on the outer shaft 402. The inner shaft 401 is comprised of two coaxial tubes to form a single elongated cannula with an integrated sharpened tip 405. In such an aspect, the inner shaft 401 can be removable from the outer shaft 402.

[0048] The puncture catheter with a removable inner shaft includes a hemostasis valve and in the handle of the catheter that is connected to an inner lumen through which the inner shaft 401 can be inserted into the puncture catheter. The extent to which the sharpened tip 405 extends from the outer shaft 402 is controlled manually at the proximal end of the inner shaft 401 near the hemostasis valve where it enters the puncture catheter.

[0049] In reference to injection catheter 400, FIG. 5 depicts a cut-away side view of the inner tube 509 and the outer tube 510 comprising the inner shaft 501. The outer tube 510 is constructed of a rigid material such as ceramic or fiber-reinforced epoxy. The inner tube 509 is made from a flexible material such as polyimide, PEBAX, grilamid, etc. This construction allows for a portion of the rigid outer tube 510 to be made flexible while maintaining a continuous lumen for fluid delivery. This is illustrated in FIG. 6.

[0050] FIG. 6 shows the inner shaft 601 with a spiral cut 611 region of the outer tube 610. Cutting the outer tube 610 using a method such as spiral-cutting, spline-cutting, etc. creates a region of the outer tube 610 that can be deflected. The inner tube 609, which is only visible through the spiral cut 611 in the outer tube 610, forms a continuous inner lumen within the outer tube 610. As such, the inner tube 610 allows fluids to be delivered through the inner shaft 601. Those of skill in the art will appreciate that the inner tube 609 and the outer tube 610 could be reversed such that the inner tube 609 is the rigid material that is cut to create a deflectable region while the outer tube 610 is the more flexible material. Constructing the inner shaft 601 in this manner allows for use of a rigid material in construction of the inner shaft 601, which results in more column strength and increased transfer of force to the sharpened tip 605.

[0051] Although inner shaft described in FIGS. 4-6 is described as comprising two coaxial tubes. It is obvious to those of skill in the art that a removable inner shaft can be made of various constructions and is not limited to the specific construction disclosed.

[0052] FIG. 7 shows another aspect of the invention where the inner shaft (not shown), puncture tip 703, and cannula 704 remain in a fixed position relative to two fixed tracking coils 706 and 708, and the outer shaft 702. In this aspect, the tip support 714 that holds the two tracking coils 706 and 708 has an inside diameter that is large enough to support an additional sliding cannula cover piece 712. The sliding cannula cover piece 712 functions to conceal the sharpened puncture tip 705 of the cannula 704 while the catheter is being navigated to the target tissue. Biasing means 713 biases the sliding cannula cover 712 in the distal position to cover the sharpened puncture tip 703. Biasing means 713 is shown as a compression spring but those of skill in the art will appreciate that any biasing means may be utilized.

[0053] FIG. 8 shows the catheter with the cannula cover 812 retracted. This can be accomplished by means of a pull wire (not shown) with one end of the pull wire attached to the proximal edge of the cannula cover 812 and the other end of the pull wire connected to a retraction mechanism in the catheter handle such as rotation knob or sliding lever. When tension is placed on the pull wire, the sliding cannula cover 812 is pulled proximally, the spring 813 is compressed, and the cannula 804 is exposed. When tension is released on the pull wire, the spring 813 extends, and the cannula cover 812 extends and conceals the cannula 804.

[0054] FIG. 9 provides a solid isometric view of an injection catheter with a retractable cannula cover 912. FIG. 9A shows the cannula cover 912 extended from the tip support 914. FIG. 9B shows the cannula cover 912 retracted into the tip support 914 with the sharpened tip 905 of cannula 904 exposed.

[0055] The injection catheter described herein can be made safe from the risk of magnetic displacement force by use of non-magnetic materials. The risk of RF heating can be eliminated by limiting conductive materials to the puncture tip, RF safe electrode lines, and transmission lines with integrated transformers.

[0056] To facilitate electrophysiological measurements during an interventional procedure, the injection catheter can include one or more electrodes. To achieve RF safety of the electrodes, RF safe electrode lines such as those described in U.S. Pat. No. 8,588,934 and U.S. Pat. No. 8,588,938 may be used to connect the electrodes to a connector in the catheter handle.

[0057] In all of the various aspects of the injection catheter disclosed herein, two tracking coils are shown; however, those of skill in the art will appreciate that the invention is not necessarily limited to two tracking coils. Rather injection catheters utilizing only one tracking coil are also intended to fall within the scope of the invention.

[0058] Although the present invention has been described with reference to various aspects of the invention, those of ordinary skill in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.