Ultrasound probe for use with transport catheter and method of making same

• US 5,363,853 A
• Filed: 06/22/1993
• Issued: 11/15/1994
• Est. Priority Date: 11/08/1991
• Status: Expired due to Term

• Current Assignee: Edwards Lifesciences Corporation
• Original Assignee: Baxter International Inc.
• Inventors: Taimisto, Miriam H., Busse, Lawrence J., Konno, Mark A., Skidmore, Robert, Swendson, David L., Lieber, Clement E.
• Primary Examiner(s): JAWORSKI, FRANCIS J
• Application Number:
  US08/080,884
• Time in Patent Office: 511 Days
• Field of Search: 128/661.07-661.10, 128/662.06, 310/334, 29/25.35
• US Class Current: 600/468
• CPC Class Codes: A61B 8/06 Measuring blood flow measuring volume flow in general G01F, e.g. G01F1/66, G01F1/72; measuring speed of fluids in general G01P5/00
• 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 25/0029 characterized by features relating to least one lumen located at the middle part of the catheter, e.g. slots, flaps, valves, cuffs, apertures, notches, grooves or rapid exchange ports catheter shaft surface irregularities A61M2025/006
• CPC Class Codes: A61M 25/003 characterized by features relating to least one lumen located at the distal part of the catheter, e.g. filters, plugs or valves catheter tips A61M25/0067
• 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: Y10T 29/42 Piezoelectric device making

Abstract

A probe for use within a catheter is disclosed. The probe transducer portion is constructed of a crystal hollow cylinder with an inside lead attached to the inner surface of the crystal cylinder. One end of the outside lead is positioned close to the outer surface, in a plane tangential to the outer surface, and is coupled to the outer surface of the crystal cylinder by a thin sputtered layer of conductive material. The probe transducer also includes a layer of acoustically absorbing material on the proximal end of the crystal, and layer of acoustically coupling material on the distal end of the crystal cylinder. The transducer element simultaneously generates an axially oriented signal beam at one frequency and a radially oriented signal beam at 2 different frequency. The signal beams are analyzed to calculate the blood flow area and the blood flow velocity, the product of which is the blood flow rate.

Claims

1. An ultrasound probe for use within a transport catheter, comprising:

a probe body having a distal and a proximal end; and

a transducer portion attached to the probe body distal end, the transducer portion further comprising;

a piezoelectric crystal hollow cylinder having a distal end and a proximal end, and further defining an inner surface and an outer surface,

an inside lead connected to the inner surface of the crystal cylinder,

a conductive material having an inner surface and an outer surface coupled to the outer surface of the crystal cylinder and extending proximally in a plane substantially tangential to the cylinder outer surface; and

an L-shaped outside lead coupled to the inner surface of the conductive material, wherein the L-shaped outside lead has a short portion and a long portion, wherein the short portion of the L-shape is positioned in close proximity to the proximate end of the crystal cylinder in the plane substantially tangential to the cylinder outer surface, such that the long portion of the L-shape extends toward the probe body and is positioned within the cylindrical volume defined by the crystal cylinder and extending proximally thereto.

2. An ultrasound probe for use within a transport catheter in accordance with claim 1 wherein the conductive material is a thin layer of conductive material selected from the group of gold and chromium.

3. An ultrasound probe for use within a transport catheter in accordance with claim 1 further comprising a layer of acoustically coupling material deposited adjacent the distal end of the crystal cylinder.

4. An ultrasound probe for use within a transport catheter in accordance with claim 3 wherein the acoustically coupling layer is comprised of an epoxy material.

5. An ultrasound probe for use within a transport catheter in accordance with claim 1 further comprising a layer of acoustically absorbing material deposited adjacent the proximal end of the crystal cylinder.

6. An ultrasound probe for use within a transport catheter in accordance with claim 5 wherein the acoustically absorbing layer is comprised of an epoxy material doped with approximately twenty-five percent rubber material.

7. An ultrasound probe for use within a transport catheter in accordance with claim 1 further comprising a connector coupled to the first and second leads at the probe body proximal end.

8. An ultrasound probe for use within a transport catheter in accordance with claim 1 wherein the probe further comprises an electrical isolation coating layer applied over crystal cylinder outer surface.

9. An ultrasound probe for use within a transport catheter in accordance with claim 1 wherein the probe body is comprised of:

a stiffener member extending from the probe body proximal end to the probe body distal end, wherein a central portion of the first and second leads are twisted around the stiffener member; and

a spring coiled and surrounding the stiffener member and twisted leads.

10. An ultrasound probe for use within a transport catheter in accordance with claim 9 wherein the stiffener member distal end is connected to the transducer by a urethane casting layer.

11. An ultrasound probe for use within a transport catheter in accordance with claim 1 wherein the probe body further includes a depth mark in close relation to the probe body proximal end, wherein the depth mark is visible when the probe is properly positioned within the catheter.

12. An ultrasound probe for use within a transport catheter in accordance with claim 1 wherein the crystal cylinder inner and outer surfaces are plated with a conductive material before the leads are coupled to the cylinder.

13. An ultrasound probe for use within a transport catheter in accordance with claim 1 further comprising;

means for providing electrical energy to the transducer element;

means for generating a radially oriented ultrasound signal beam at a first frequency from the transducer element;

means for generating an axially oriented ultrasound signal beam at a second frequency from the transducer element;

means for analyzing the radially oriented signal beam to calculate the cross-sectional area of the blood vessel;

means for analyzing the axially oriented signal beam to calculate the blood flow velocity in the blood vessel; and

means for analyzing the cross-sectional area and the blood flow velocity to calculate the blood flow rate in the blood vessel.

14. A method of manufacturing an ultrasound probe comprising the steps of:

forming an elongated probe body having a proximal and a distal end;

providing a crystal hollow cylinder having an inner surface, an outer surface, a proximal end, and a distal end;

connecting an inside lead to the inner surface of the cylinder;

forming an outside lead into an L-shape having a short portion and a long portion;

applying a thin layer of conductive material having an inner surface and an outer surface to the outer surface of the crystal cylinder and extending proximally in a plane substantially tangential to the cylinder outer surface;

positioning the short portion of the outside lead in close proximity to the proximal end of the crystal cylinder outer surface and coupling the short portion to the inner surface of the conductive material in the plane substantially tangential to the cylinder outer surface, such that the long portion of the L-shape extends toward the probe body and is positioned within the cylindrical volume defined by the crystal cylinder outer surface and extending proximally thereto; and

connecting the probe body distal end to the crystal cylinder proximal end.

15. A method of manufacturing an ultrasound probe in accordance with claim 14 further comprising the step of disposing the crystal cylinder within a casting layer and depositing an acoustically coupling layer adjacent the distal end of the crystal cylinder.

16. A method of manufacturing an ultrasound probe in accordance with claim 14 further comprising the step of disposing the crystal cylinder within a casting layer and depositing an acoustically absorbing layer adjacent the proximal end of the crystal cylinder.

17. A method of manufacturing an ultrasound probe in accordance with claim 14 further comprising the step of plating the inner surface and the outer surface of the crystal cylinder with a conductive material before attaching the leads to the crystal cylinder.

18. A method of manufacturing an ultrasound probe in accordance with claim 14 wherein the step of forming the probe body further comprises the steps of:

providing a stiffener member that extends from the probe body distal end to the probe body proximal end;

twisting a central portion of the inside and outside leads around the stiffener member; and

surrounding the stiffener member and twisted leads with a flat spring.

19. A method of manufacturing an ultrasound probe in accordance with claim 14 further comprising the step of marking the probe body with a depth mark in close relation to the probe body proximal end, wherein the depth mark is positioned such that the depth mark is visible when the probe is properly positioned within the catheter.

20. A method of manufacturing an ultrasound probe in accordance with claim 14 further comprising the step of connecting the probe body to the transducer portion by a urethane casting layer.

21. A method of manufacturing an ultrasound probe in accordance with claim 14 further comprising the step of selecting the conductive material from a group consisting of gold and chromium.

22. A catheter for accepting an ultrasound probe and other probes, and for introducing fluid through the catheter and into a body cavity comprising:

a catheter, the catheter comprising a catheter body having a continuous outer edge surface with a corresponding maximum outer dimension and having a proximal end and a distal end and having walls defining in transverse cross-section, lumens including;

a first wall defining a first lumen having a cross-sectional dimension approximately half the outer dimension of the catheter body;

a second wall defining a curved lumen wherein the lumen occupies at least a quarter of an arc around the catheter body; and

an ultrasound probe for use within the first lumen, the probe having a cross-sectional dimension less than the first lumen cross-sectional dimension and including;

a probe body having a proximal end and a distal end;

a transducer portion attached to the probe body distal end, the transducer portion further comprising;

a piezoelectric crystal hollow cylinder having a proximal end and a distal end, and further defining an inner surface and an outer surface;

an inside lead connected to the inner surface of the crystal cylinder;

a thin layer of conductive material having an inner surface and an outer surface coupled to the outer surface of the crystal cylinder and extending proximally in a plane substantially tangential to the cylinder outer surface; and

an L-shaped outside lead coupled to the inner surface of the conductive material, wherein the L-shaped outside lead has a long portion and a short portion, wherein the short portion is positioned in close proximity to the proximal end of the crystal cylinder in the plane substantially tangential to the cylinder outer surface, such that the long portion of the L-shape extends toward the probe body and is positioned within the cylindrical volume defined by the crystal cylinder outer surface and extending proximally thereto.

23. A catheter for accepting probes and for introducing fluid through the catheter and the body in accordance with claim 22 wherein the transducer portion further comprises a layer of acoustically coupling material deposited adjacent the distal end of the crystal.

24. A catheter for accepting probes and for introducing fluid through the catheter and the body in accordance with claim 23 wherein the acoustically coupling layer is comprised of an epoxy material.

25. A catheter for accepting probes and for introducing fluid through the catheter and the body in accordance with claim 22 wherein the transducer portion further comprises a layer of acoustically absorbing material deposited adjacent the proximal end of the crystal cylinder.

26. A catheter for accepting probes and for introducing fluid through the catheter and the body in accordance with claim 25 wherein the acoustically absorbing layer is comprised of an epoxy material doped with approximately twenty-five percent rubber material.

27. A catheter for accepting probes and for introducing fluid through the catheter and the body in accordance with claim 22 wherein the probe body is comprised of:

a stiffener member extending from the probe body proximal end to the probe body distal end, wherein a central portion of each of the inside and outside leads are twisted around the stiffener member; and

a spring surrounding the stiffener member and twisted leads.

28. A catheter for accepting probes and for introducing fluid through the catheter and the body in accordance with claim 22 wherein the probe body further includes a depth mark, wherein the probe body is visible when the probe is properly positioned within the catheter.

29. A transducer for use in an ultrasound probe comprising:

a piezoelectric crystal hollow cylinder having a distal end and a proximal end, and further defining an inner surface and an outer surface;

an inside lead having a first end connected to the inner surface of the crystal cylinder;

a thin layer of conductive material having an inner surface and an outer surface coupled to the outer surface of the crystal cylinder and extending proximally in a plane substantially tangential to the cylinder outer surface;

an outside lead having a first end coupled to the inner surface of the conductive material, wherein the outside lead first end is positioned in close proximity to the proximal end of the crystal cylinder in the plane substantially tangential to the cylinder outer surface, such that substantially all of the outside lead is positioned within the cylindrical volume defined by the crystal cylinder and extending proximally thereto.

30. A transducer for use in an ultrasound probe in accordance with claim 29 wherein the thin layer of conductive material is selected from the group consisting of gold and chromium.

31. A transducer for use in an ultrasound probe in accordance with claim 29 further comprising a layer of acoustically coupling material deposited adjacent the distal end of the crystal cylinder.

32. A transducer for use in an ultrasound probe in accordance with claim 29 further comprising a layer of acoustically absorbing material deposited adjacent the proximal end of the crystal cylinder.

33. A transducer for use in an ultrasound probe in accordance with claim 29 further comprising an electrical isolation coating layer applied over the crystal cylinder outer surface.

34. A transducer for use in an ultrasound probe in accordance with claim 29 wherein the crystal cylinder inner and outer surfaces are plated with a conductive material before the leads are coupled to the cylinder.

35. A transducer for use in an ultrasound probe in accordance with claim 29 further comprising:

means for providing electrical energy to the transducer element;

means for generating a radially oriented ultrasound signal beam at a first frequency from the transducer element;

means for generating an axially oriented ultrasound signal beam at a second frequency from the transducer element;

means for analyzing the radially oriented signal beam to calculate the cross-sectional area of the blood vessel;

means for analyzing the axially oriented signal beam to calculate the blood flow velocity in the blood vessel; and

means for analyzing the cross-sectional area and the blood flow velocity to calculate the blood flow rate in the blood vessel.

36. An ultrasound probe for measuring the blood flow rate in a blood vessel comprising:

a single cylindrical transducer element defining an axis and a radius;

means for providing electrical energy to the transducer element;

means for generating a radially oriented ultrasound signal beam at a first frequency from the transducer element;

means for generating an axially oriented ultrasound signal beam at a second frequency from the transducer element;

means for analyzing the radially oriented signal beam to calculate the cross-sectional area of the blood vessel;

means for analyzing the axially oriented signal beam to calculate the blood flow velocity in the blood vessel; and

means for analyzing the cross-sectional area and the blood flow velocity to calculate the blood flow rate in the blood vessel.

37. An ultrasound probe for measuring the blood flow in a blood vessel in accordance with claim 36 further comprising means for simultaneously generating the radially oriented and axially oriented beams from the transducer element.

38. An ultrasound probe for use within a transport catheter, comprising:

a probe body having a distal and a proximal end;

a transducer portion attached to the probe body distal end, the transducer portion further comprising;

a piezoelectric crystal hollow cylinder having a distal end and a proximal end, and further defining an inner surface and an outer surface,

an inside lead connected to the inner surface of the crystal cylinder,

a conductive material having an inner surface and an outer surface coupled to the outer surface of the crystal cylinder and extending proximally in a plane substantially tangential to the cylinder outer surface; and

an L-shaped outside lead coupled to the inner surface of the conductive material, wherein the L-shaped outside lead has a short portion and a long portion, wherein the short portion of the L-shape is positioned in close proximity to the proximate end of the crystal cylinder in the plane substantially tangential to the cylinder outer surface, such that the long portion of the L-shape extends toward the probe body and is positioned within the cylindrical volume defined by the crystal cylinder and extending proximally thereto;

means for providing electrical energy to the transducer element;

means for generating a radially oriented ultrasound signal beam at a first frequency from the transducer element;

means for generating an axially oriented ultrasound signal beam at a second frequency from the transducer element;

means for analyzing the radially oriented signal beam to calculate the cross-sectional area of the blood vessel;

means for analyzing the axially oriented signal beam to calculate the blood flow velocity in the blood vessel; and

means for analyzing the cross-sectional area and the blood flow velocity to calculate the blood flow rate in the blood vessel.

39. A transducer for use in an ultrasound probe comprising:

a piezoelectric crystal hollow cylinder having a distal end and a proximal end, and further defining an inner surface and an outer surface;

an inside lead having a first end connected to the inner surface of the crystal cylinder;

a thin layer of conductive material having an inner surface and an outer surface coupled to the outer surface of the crystal cylinder and extending proximally in a plane substantially tangential to the cylinder outer surface;

an outside lead having a first end coupled to the inner surface of the conductive material, wherein the outside lead first end is positioned in close proximity to the proximal end of the crystal cylinder in the plane substantially tangential to the cylinder outer surface, such that substantially all of the outside lead is positioned within the cylindrical volume defined by the crystal cylinder and extending proximally thereto;

means for providing electrical energy to the transducer element;

means for generating a radially oriented ultrasound signal beam at a first frequency from the transducer element;

means for generating an axially oriented ultrasound signal beam at a second frequency from the transducer element;

means for analyzing the radially oriented signal beam to calculate the cross-sectional area of the blood vessel;

means for analyzing the axially oriented signal beam to calculate the blood flow velocity in the blood vessel; and

means for analyzing the cross-sectional area and the blood flow velocity to calculate the blood flow rate in the blood vessel.