Apparatus, system and method for measuring spatial average velocity and/or volumetric flow of blood in a vessel

• US 4,967,753 A
• Filed: 01/13/1989
• Issued: 11/06/1990
• Est. Priority Date: 04/10/1987
• Status: Expired due to Term

• Current Assignee: Volcano Corporation (Koninklijke Philips N.V.)
• Original Assignee: Cardiometrics, Inc. (Koninklijke Philips N.V.)
• Inventors: Christian, Jeffrey J., Haase, Wayne C., Corl, Paul D., Segal, Jerome, Williams, Ronald G.
• Primary Examiner(s): Jaworski, Francis
• Application Number:
  US07/297,111
• Time in Patent Office: 662 Days
• Field of Search: 128/772, 128/662.06, 128/4, 606/194
• 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 2025/09175 having specific characteristics at the distal tip
• CPC Class Codes: G01F 1/663 by measuring Doppler frequency shift

Abstract

System for measuring a characteristic of flow of liquid in a vessel of a patient comprising a transducer positioned in a vessel in a patient for supplying ultrasonic energy. The transducer produces a substantially uniform beam which encompasses the vessel. The transducer receives ultrasonic energy back scattered from the red blood cells and provides an electrical output signal. A first moment detector is provided which receives the electrical output from the transducer and provides a first moment signal. Normalization is provided to the output of the first moment detector to provide an electrical output representing a characteristic of the flow of the liquid in the vessel.

Claims

1. In a device for use in measuring a characteristic of liquid flow in a vessel, a flexible elongate tubular member having proximal and distal extremities having an exterior diameter of 0.018 inches or less, a coil spring carried by the distal extremity of the flexible elongate tubular member and having an exterior diameter of 0.018 inches or less, the coil spring having a distal extremity, a transducer carried by the distal extremity of the coil spring and having an exterior diameter of 0.018 inches or less, conductive means connected to the transducer and extending interiorly of the coil spring and of the flexible elongated tubular member and protective means carried by the coil spring and engaging the elongated tubular member and serving to prevent liquid in the vessel from coming into contact with the conductive means extending through the coil spring and the flexible elongate tubular member.

2. A device as in claim 1 wherein said flexible elongate member is in the form of a guide wire.

3. A device as in claim 1 wherein said protective means includes a conformal coating carried by the coil spring.

4. A device as in claim 1 together with a core wire extending from the tubular member and into the coil spring, first and second joints for connecting the coil spring to the core wire and wherein said protection means includes a protective sheath surrounding the conductive means and extending between the first and second joints to protect the conductive means from liquid in the vessel.

5. A device as in claim 4 wherein said protective means includes a conformal coating disposed on said coil spring and on said transducer.

6. In a guide wire for use in measuring a characteristic of liquid flow in a vessel, a flexible elongate tubular element having proximal and distal extremities, a core wire extending through at least a portion of the flexible elongate tubular element and having a tapered distal extremity extending beyond the distal extremity of the tubular element, a coil extending over and beyond the distal extremity of the core wire, the coil having a proximal extremity and a distal extremity, means securing the proximal extremity of the coil to the distal extremity of the tubular element, transducer means secured to the distal extremity of the coil, first and second conductor means carried by the tubular element and connected to the transducer and extending to the proximal extremity of the tubular element, means bonding the tubular element and the coil to the core wire so that torsional forces applied to the tubular element are supplied to the coil and protective means associated with the coil and the tubular element for preventing liquid in the vessel from coming into contact with the first and second conductor means extending through the coil and the tubular element.

7. A guide wire as in claim 6 wherein said first conductor means includes the flexible tubular element and said second conductor means includes the core wire together with electrical insulation means disposed between the tubular element and the core wire.

8. A guide wire as in claim 6 wherein said first conductor means includes a conductive wire helically wound onto said core wire and insulation means insulating said helically wound conductive wire from said tubular element and from said core wire, said insulating means also serving to insulate the tubular element from the core wire so that the tubular element can serve as an electrical noise shield and wherein said second conductor means includes said core wire.

9. A guide wire as in claim 6 wherein said second conductor means also includes a braided conductive element extending from said transducer to said core wire and being electrically connected to said transducer and to said core wire.

10. A guide wire as in claim 6 together with a braided wire-like element connecting the distal extremity of said core wire to said transducer.

11. A guide wire as in claim 10 wherein said braided wire-like element is formed of at least three strands of a beryllium copper wire.

12. A guide wire as in claim 6 wherein said transducer means has a forwardly facing surface together with a lens having a rounded surface mounted on said forwardly facing surface.

13. A guide wire as in claim 12 wherein the lens is formed of a plastic and wherein the rounded surface is formed by the use of surface tension to provide a rounded surface having a high quality lens surface finish which facilitates the formation of a beam pattern of ultrasonic energy without substantial scattering of ultrasonic energy.

14. A guide wire as in claim 6 wherein said first and second conductor means are helically wound onto said core wire together with insulating means for separating said first and second conductor means from said core wire and from said flexible elongate element.

15. A guide wire as in claim 6 wherein said tubular element and said core wire are formed of stainless steel.

16. A guide wire as in claim 6 wherein said coil has at least a portion thereof formed of a material which is relatively opaque to x-rays.

17. A guide wire as in claim 6 together with a conductor cable secured to the proximal extremity of said tubular element and having conductors connected to said first and second conductor means.

18. A guide wire as in claim 6 wherein said core wire extends through the length of the flexible elongate tubular element.

19. A guide wire as in claim 6 wherein the core wire terminates in the tubular element at a point which is spaced a substantial distance from the proximal extremity of the tubular element.

20. A guide wire as in claim 6 wherein said first and second conductor means are in the form of first and second conductive wires extending from the transducer to the proximal extremity of the flexible tubular element interior of the flexible tubular element.

21. A guide wire as in claim 20 together with a braid extending from the transducer interiorly of the coil and a joint for securing the braid to the coil at a point spaced from the distal extremity of the coil.

22. A guide wire as in claim 21 wherein the core wire terminates at a point which is spaced from the transducer.

23. A guide wire as in claim 21 wherein said braid is formed of stainless steel.

24. A guide wire as in claim 6 wherein said protective means includes a conformal coating extending over the coil.

25. A guide wire as in claim 24 together with a conformal coating disposed on the transducer.

26. A guide wire as in claim 6 wherein said means for bonding the tubular element and the coil to the core wire includes first and second joints together with a sheath of protective material disposed within the coil and extending between the first and second joints to protect the first and second conductor means extending therethrough from exposure to the liquid in the vessel and from mechanical abrasion.