Acoustic imaging and doppler catheters and guidewires

• US 6,074,349 A
• Filed: 08/11/1997
• Issued: 06/13/2000
• Est. Priority Date: 11/30/1994
• Status: Expired due to Fees

• Current Assignee: Boston Scientific Corporation
• Original Assignee: Boston Scientific Corporation
• Inventors: Crowley, Robert J.
• Primary Examiner(s): Jaworski, Francis J.
• Application Number:
  US08/909,414
• Time in Patent Office: 1,037 Days
• Field of Search: 600/455, 600/439, 600/461-463, 600/468, 600/465-467
• US Class Current: 600/463
• 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 8/13 Tomography A61B8/10, A61B8/12 take precedence; tomography for radiation diagnosis A61B6/02
• CPC Class Codes: A61B 8/445 Details of catheter construction
• CPC Class Codes: A61B 8/4461 Features of the scanning mechanism, e.g. for moving the transducer within the housing of the probe
• CPC Class Codes: G01N 2291/017 Doppler techniques
• CPC Class Codes: G01N 2291/02836 Flow rate, liquid level
• CPC Class Codes: G01N 2291/2636 cylindrical from inside
• CPC Class Codes: G01N 29/0672 by acoustic tomography medical tomography A61B8/13
• CPC Class Codes: G01N 29/221 Arrangements for directing or focusing the acoustical waves electronic orientation or focusing G01N29/262; sound directing or focusing G10K11/26; mechanical steering of sound transducers or their beams G10K11/35
• CPC Class Codes: G01N 29/265 by moving the sensor relative to a stationary material
• CPC Class Codes: G01S 15/894 by rotation about a single axis
• CPC Class Codes: G01S 15/8943 co-operating with reflectors
• CPC Class Codes: G01S 15/8979 Combined Doppler and pulse-echo imaging systems
• CPC Class Codes: G01S 7/52036 using analysis of echo signal for target characterisation
• CPC Class Codes: G10K 11/28 using reflection, e.g. parabolic reflectors

Abstract

The invention features an acoustic medical device for making Doppler measurements and imaging within a body fluid conduit using a single-transducer. The device has an elongated device body, defining a device axis, constructed for positioning a distal end of the device body near a region of interest in the body fluid conduit. Disposed within the device body is an ultrasonic beam directing assembly that is constructed to direct a portion of ultrasonic energy from a single transducer in a direction for imaging within the body fluid conduit and to direct another portion of the ultrasonic energy in a direction for making Doppler measurements within the body fluid conduit.

Claims

1. A medical device for making Doppler measurements and imaging within a body fluid conduit using a single transducer, comprising:

an elongated device body defining a device axis and constructed for positioning a distal end of said device body near a region of interest in said body fluid conduit, and disposed within said device body, an ultrasonic beam-directing assembly constructed to direct a first portion of a given beam of ultrasonic energy from said single transducer in a direction for imaging within said body fluid conduit and to direct a second portion of said given beam of said ultrasonic energy in a different direction for making Doppler measurements within said body fluid conduit.

2. The device of claim 1 wherein said first portion of said ultrasonic energy is directed in a direction generally transverse to said device axis for imaging within said body fluid conduit and said second portion of said ultrasonic energy is directed in a direction generally along said device axis for making Doppler measurements within said body fluid conduit.

3. The device of claim 1 wherein said ultrasonic beam-directing assembly includes an ultrasonic beam splitter to spatially separate ultrasonic energy from said transducer into said first portion for providing an image of a wall of a body lumen and said second portion for making Doppler measurements of the flow of fluid in said body fluid conduit.

4. The device of claim 3 wherein said beam splitter is a partially sonolucent polymeric material spaced from said transducer in the path of said ultrasonic energy.

5. The device of claim 4 wherein said partially sonolucent polymeric material is located transversely with respect to said device axis.

6. The device of claim 4 wherein said partially sonolucent polymeric material forms at least a portion of the wall of said device body.

7. The device of claim 6 wherein the wall of said device body is shaped to efficiently direct said second portion of energy for making Doppler measurements generally along the axis of said device body.

8. The device of claim 7 wherein said device body has a flared distal end.

9. The device of claim 6 wherein said wall of said device body comprises angled ridges formed in a manner so as to gradually redirect said second portion of said ultrasonic energy generally along said device axis for making Doppler measurements within said body fluid conduit.

10. The device of claim 1 wherein said second portion of ultrasonic energy for making Doppler measurements is directed at an exit angle of 15°

or less with respect to the device axis.

11. The device of claim 1 wherein the distal end of said device body is open.

12. The device of claim 1 wherein the distal end of said device body is closed and comprises sonolucent material.

13. The device of claim 12 constructed for varying the transmissivity and reflectivity of said beam-directing assembly by varying the acoustic impedance of said ultrasonic beam splitter.

14. The device of claim 13 constructed for varying the impedance of said ultrasonic beam splitter by flowing fluids of varying impedance behind said ultrasonic beam splitter.

15. The device of claim 13 constructed for varying impedance of said ultrasonic beam splitter by varying the thickness of a partially sonolucent beam directing material.

16. The device of claim 1 further comprising an analysis circuit that includes a timing circuit and a switch such that the ultrasonic imaging signal from said first portion of ultrasonic energy for imaging can be differentiated from the ultrasonic Doppler signal from said second portion of ultrasonic energy for making Doppler measurements by time delay between said signals, and said ultrasonic imaging signal and said Doppler signal can be separately analyzed by imaging and Doppler electronics.

17. The device of claim 1 wherein said beam directing assembly is an acoustically reflective ring disposed within said device body, a portion of said device body being formed from a sonolucent material.

18. The device of claim 1 wherein said transducer is mounted on a hinge constructed to permit said transducer to rotate between at least two angles.

19. The device of claim 1 wherein at least two facets are mounted on said transducer constructed to permit said transducer to emit ultrasonic energy in two spatially separate directions simultaneously.

20. The device of claim 1 wherein said first portion of ultrasonic energy and said second portion of ultrasonic energy are substantially perpendicular with respect to each other.

21. The device of claim 1 wherein the beam directing assembly is rotatable.

22. The device of claim 1 wherein said ultrasonic beam directing assembly is coupled to said transducer.

23. The device of claim 22 wherein said ultrasonic beam directing assembly and said transducer are both simultaneously rotatable.

24. A method for making Doppler measurements and imaging within a body fluid conduit, said method comprising the steps of:

introducing a medical device into a patient'"'"'s body fluid conduit, said medical device including an ultrasonic transducer and an ultrasonic beam-directing assembly near the distal end of said device;

positioning said distal end near a region of interest within said body fluid conduit;

directing ultrasonic energy from said transducer to said beam-directing assembly for directing a first portion of said energy in a first direction for imaging within said body fluid conduit and for simultaneously directing a second portion of said energy in a second, different direction for making Doppler measurements within said body fluid conduit; and

receiving the reflected energy back containing the image and flow information.

25. A method as in claim 24 wherein the ultrasonic beamdirecting assembly is an ultrasonic beam splitter which spatially separates said ultrasonic energy from said transducer into a first portion for providing an image of a wall of said body fluid conduit and a second portion for making Doppler measurements of the flow of fluid in said body fluid conduit.