Medical diagnostic ultrasound catheter with dielectric isolation

• US 7,232,433 B1
• Filed: 09/22/1999
• Issued: 06/19/2007
• Est. Priority Date: 09/22/1999
• Status: Expired due to Term

• Current Assignee: Siemens Medical Solutions USA Incorporated (Siemens AG)
• Original Assignee: Siemens Medical Solutions USA Incorporated (Siemens AG)
• Inventors: Schlesinger, Randall L., Rahimi, Mathew
• Primary Examiner(s): WILLIAMS, CATHERINE SERKE
• Application Number:
  US09/401,632
• Time in Patent Office: 2,827 Days
• Field of Search: 604 20- 22, 604/523, 604/524, 604/527, 600443-447, 600/437, 600/462, 600/466, 600/467
• US Class Current: 604/527
• CPC Class Codes: A61B 8/12 in body cavities or body tracts, e.g. by using catheters catheters per se A61M25/00
• CPC Class Codes: A61B 8/445 Details of catheter construction
• CPC Class Codes: A61M 2025/0034 characterized by elements which are assembled, connected or fused, e.g. splittable tubes, outer sheaths creating lumina or separate cores making of catheters A61M25/0009
• CPC Class Codes: A61M 2025/0036 with more than four lumina
• CPC Class Codes: A61M 25/0032 characterized by at least one unconventionally shaped lumen, e.g. polygons, ellipsoids, wedges or shapes comprising concave and convex parts
• CPC Class Codes: A61M 25/005 with embedded materials for reinforcement, e.g. wires, coils, braids

Abstract

Medical diagnostic ultrasound catheters are provided with improved materials for dielectric withstand strength. In one aspect, the catheter includes a braid of non-conductive material. The non-conductive braid reduces the capacitive: coupling effects and allows smaller catheters or a greater number of conductors. The non-conductive braid provides both compressive and tensile strength to transmit the torque applied to the catheter. The non-conductive braid also allows fusing of components while decreasing the risk of defective manufacture. In another aspect, a dielectric film, such as a polyester film, is positioned between the transducer and any lens or window. The dielectric film allows thinner window lenses to be used, allowing smaller catheters or larger transducers. The dielectric film may also increase the sensitivity of the transducer to acoustic energy. The dielectric film prevents the lens or window material from filling kerfs in the transducer, which may eliminate the need for filling the kerfs of the transducer.

Claims

1. A medical diagnostic ultrasound catheter for imaging from within a body, the catheter comprises:

a conductor;

a shaft surrounding at least a portion of the conductor;

a non-conductive braid connected with the shaft; and

an ultrasound transducer connected with the shaft and electrically connected with the conductor

wherein the ultrasound transducer is positioned in a tip portion of the shaft, the tip portion of the shaft being free of the non-conductive braid;

wherein the shaft is free of electrically conductive material.

2. The catheter of claim 1 wherein the non-conductive braid comprises a braid of mono-filament material.

3. The catheter of claim 1 wherein the non-conductive braid comprises mono-filament nylon material.

4. The catheter of claim 1 wherein the non-conductive braid comprises a material selected from the group consisting of:

glass, plastic, nylon and combinations thereof.

5. The catheter of claim 1 wherein the non-conductive braid is embedded within the shaft.

6. The catheter of claim 1 wherein the shaft comprises a tip portion fused to a body portion, the non-conductive braid connected with the body portion.

7. The catheter of claim 1 wherein the non-conductive braid comprises a configuration selected from the group consisting of:

spiral, diamond weave and combinations thereof.

8. The catheter of claim 1 further comprising a dielectric film adjacent an emitting surface of the ultrasound transducer.

9. The catheter of claim 1 wherein the non-conductive braid comprises liquid crystal polymer material.

10. A medical diagnostic ultrasound catheter for imaging from within a body, the catheter comprising:

a catheter shaft;

an ultrasound transducer connected with the catheter shaft;

a lens adjacent the ultrasound transducer, the lens having a focus; and

a dielectric solid film adjacent the ultrasound transducer, the dielectric solid film comprising a polyester film;

wherein;

the catheter shaft comprises a tip portion;

the ultrasound transducer connects with the tip portion; and

the dielectric film surrounds a circumference of the ultrasound transducer, the circumference being over an emitting surface, a back and at least two sides of the ultrasound transducer.

11. The catheter of claim 10 wherein the dielectric film is positioned between the lens or window and the ultrasound transducer.

12. The catheter of claim 10 wherein the dielectric film-comprises a tape material.

13. The catheter of claim 10 wherein the polyester film comprises Mylar.

14. The catheter of claim 10 wherein the dielectric film comprises a film having a thickness less than 7 microns.

15. The catheter of claim 10 wherein the dielectric film is positioned adjacent an emitting surface of the ultrasound transducer.

16. The catheter of claim 10 further comprising a non-conductive braid connected with the shaft.

17. The catheter of claim 10 wherein the dielectric surrounds the circumference and one end of the ultrasound transducer.

18. The catheter of claim 11 further comprising a flexible circuit connected with the ultrasound transducer, the dielectric film being separate from the flexible circuit, the flexible circuit being between the transducer and the dielectric film.

19. A medical diagnostic ultrasound catheter for imaging from within a body, the catheter comprising:

a shaft;

an ultrasound transducer connected within the shaft; and

a dielectric solid film positioned between a portion of the shaft and the ultrasound transducer, wherein the dielectric surrounds at least a portion of a circumference and one end of the ultrasound transducer, the dielectric solid film having a thickness less than 7 microns.

20. The catheter of claim 19 further comprising a lens adjacent the ultrasound transducer, wherein the dielectric film is positioned between the lens and the ultrasound transducer.

21. The catheter of claim 19 wherein the dielectric film comprises a polyester film.

22. The catheter of claim 19 further comprising a non-conductive braid connected with the shaft.

23. A medical catheter for insertion into a body, the catheter comprising:

a shaft;

an electrical conductor connected with a transducer within the shaft; and

a nonconductive braid connected with the shaft to transmit torque to the shaft wherein the ultrasound transducer is positioned in a tip portion of the shaft, the tip portion of the shaft being fee of the non-conductive braid;

wherein the shaft is free of electrically conductive material.

24. The catheter of claim 23 wherein the non-conductive braid comprises a braid of mono-filament material.

25. The catheter of claim 23 wherein the non-conductive braid comprises mono-filament liquid crystal polymer material.

26. The catheter of claim 23 wherein the non-conductive braid comprises a material selected from the group consisting of:

glass, plastic, nylon and combinations thereof.

27. The catheter of claim 23 wherein the non-conductive braid is embedded within the shaft.

28. The catheter of claim 23 further comprising;

an ultrasound transducer electrically connected to the conductor.

29. The catheter of claim 23 further comprising a control within the shaft.

30. A medical diagnostic ultrasound catheter for imaging from within a body, the catheter comprising:

a catheter shaft;

an ultrasound transducer connected with the catheter shaft;

a dielectric film positioned between a portion of the catheter shaft and the ultrasound transducer; and

a lens adjacent the ultrasound transducer, wherein the dielectric film is positioned between the lens and the ultrasound transducer;

wherein the dielectric film surrounds a circumference of the ultrasound transducer.

31. The catheter of claim 30 further comprising a flexible circuit connected with the ultrasound transducer, the dielectric film being separate from the flexible circuit, the flexible circuit being between the transducer and the dielectric film.