System and method for detecting, localizing, and characterizing occlusions, stent positioning, dissections and aneurysms in a vessel

• US 6,193,669 B1
• Filed: 12/11/1998
• Issued: 02/27/2001
• Est. Priority Date: 12/11/1998
• Status: Expired due to Fees

• Current Assignee: Florence Medical Limited
• Original Assignee: Florence Medical Limited
• Inventors: Shalman, Evgeny, Tyomkin, Alexander, Degany, Elhanan, Barak, Chen, Noskowicz, Simon Henri
• Primary Examiner(s): O'Connor, Cary
• Assistant Examiner(s): CARTER, RYAN CHRISTOPHER
• Application Number:
  US09/210,002
• Time in Patent Office: 809 Days
• Field of Search: 600/485-486, 600/500, 600/504-505, 600/454, 600/481, 600/561
• US Class Current: 600/486
• CPC Class Codes: A61B 5/02014 Determining aneurysm
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61B 5/103 Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes A61B5/08 takes precedence; measuring aids for tailors A41H1/00; measuring instruments specially adapted for dentistry A61C19/04
• CPC Class Codes: A61B 5/6851 Guide wires
• CPC Class Codes: A61B 5/6852 Catheters

Abstract

This invention relates to a method and devices for detection, localization and characterization of occlusions, aneurysms, dissections stent position, dissections stent mal-position, wall characteristics and vascular bed. The invention is based on introducing an artificial pressure or flow excitation signal (a single signal or more) into the blood vessel (or in other tubular flowing fluid conduits), measurement and analysis of the pressure and or flow. The invention discloses a method and devices for detection and characterization of partial or total occlusion or aneurysm in blood vessels or in other tubular flowing fluid conduits within a body, such as urine flow in the urethra.

Claims

1. An apparatus for detecting, locating and characterizing changes in a tubular conduit system within a living body for transferring fluids, said apparatus comprising:

a signal generator configured to transmit into said tubular conduit a probe signal that changes in response to encountering changes in said tubular conduit system;

a signal sensor operative to receive said probe signal following transmission into said tubular conduit system;

a processor unit operatively connected to said signal sensor;

a program for controlling the processor unit;

said processor unit operative with said program to receive said probe signal following transmission through said tubular conduit system;

identify changes in said probe signal;

detect characteristics of said tubular conduit system, said characteristics of said tubular conduit system being derived from changes in said probe signal; and

recognize and assign a value of said characteristic of said tubular conduit system.

2. The apparatus according to claim 1, wherein said processor unit is operative to select a method from a plurality of methods to identify changes in said probe signal and therefrom detect changes in said tubular conduit system.

3. The apparatus according to claim 1, wherein said tubular conduit system is a blood vessel system and said processor unit is operative to detect changes in arterial characteristics.

4. The apparatus according to claim 3 wherein said processor unit is operative to detect aneurysms.

5. The apparatus according to claim 3 wherein said processor unit is operative to detect stenosis.

6. The apparatus according to claim 3 wherein said processor unit is operative to detect arterial occlusions.

7. The apparatus according to claim 1 wherein said signal generator is a pressure signal generator.

8. The apparatus according to claim 1 wherein said signal generator is a flow signal generator.

9. The apparatus according to claim 7 wherein said signal sensor is a pressure sensor.

10. The apparatus according to claim 8 wherein said signal sensor is a pressure sensor.

11. The apparatus according to claim 7 wherein said signal sensor is a flow sensor.

12. The apparatus according to claim 7 wherein said signal sensor is adapted to measure change in a cross-sectional diameter of said tubular conduit.

13. The apparatus according to claim 7 wherein said signal sensor is an intravascular flow sensor.

14. The apparatus according to claim 7 wherein said signal sensor is an external imaging device.

15. The apparatus according to claim 3 wherein said arterial characteristics are selected from the group consisting of aneurysms, stenosis, occlusion, dissection and stent multipositioning.

16. The apparatus according to claim 8 wherein said signal sensor is a flow sensor.

17. The apparatus according to claim 8 wherein said signal sensor is adapted to measure change in a cross-sectional diameter of said tubular conduit.

18. The apparatus according to claim 8 wherein said signal sensor is an intravascular flow sensor.

19. The apparatus according to claim 8 wherein said signal sensor is an external imaging device.

20. The apparatus according to claim 3 wherein said signal generator is a pressure signal generator;

said signal sensor is a pressure signal sensor; and

said processor unit is operative to receive a heart beat signal; and

synchronize receipt of said probe signal with said heart beat signal.

21. The apparatus according to claim 3 wherein said probe signal is a plurality of discrete signals;

said processor unit is operative to sample said discrete signals and receive and calculate pressure wave velocity data.

22. The apparatus according to claim 21 wherein said processor unit is operative to perform a single pressure function using said discrete signals and said pressure wave velocity data.

23. The apparatus according to claim 21 wherein said processor unit is adapted to characterize the distensibility and the compliance of lesioned and non-lesioned parts of blood vessels.

24. The apparatus of claim 22 wherein said processor unit when performing said single pressure function is operative to calculate an allpass value and a cepstrum value from said minimum phase component;

separate a regular part and a singular part of said cepstrum value, where said singular part and said regular part form said pressure wave;

calculate an exponential function of singular part;

evaluate a second peak time delay with respect to a forward found in said pressure signal;

evaluate a coefficient by calculation of a second peak amplitude to determine an arterial characteristic; and

evaluate a location and severity of said arterial characteristic.

25. The apparatus of claim 3 wherein said signal sensor includes two sensing transducers disposed in spaced apart relation.

26. The apparatus of claim 25 wherein said processor unit is operative to receive a forward pressure wave signal from a first transducer and a probe signal represented by a plurality of discrete signals sampled overtime.

27. The apparatus according to claim 26 wherein said processor unit is operative to perform a dual pressure function.

28. The apparatus of claim 27 wherein said processor unit when performing said dual pressure function is operative to:

calculate an allpass component and cepstrum component of a minimum phase component of said forward pressure wave signal received from said signal sensor;

apply an inverse filtering of said forward pressure wave signal;

apply smoothing by a B-spline function;

detect a forward peak location by a global maximum calculation;

receive a threshold value;

detect a second peak location by comparison with said threshold, where said threshold is derived from a forward peak maximum value and minimum size of a characteristic;

evaluate a second peak time delay with respect to said forward peak;

evaluate a reflection coefficient by calculating a forward and reflected peak area; and

evaluate a location and severity of said characteristic.

29. The apparatus according to claim 25 wherein said processor unit is operative to calculate a pressure wave velocity from a pressure wave sensed by said first and second transducers.

30. The apparatus according to claim 3 wherein said signal sensor is movable between at least two positions relative to said tubular conduit system and said processor unit is operative to calculate a pressure wave velocity from signals received from said two positions.

31. The apparatus according to claim 1 wherein said processor unit includes an analog to digital convertor.

32. The apparatus according to claim 1 wherein said signal sensor includes a signal conditioner.

33. The apparatus according to claim 1, wherein said tubular conduit system is a urinary vessel system and said processor unit is operative to detect changes in urinary tract characteristics.

34. The apparatus according to claim 1, wherein said processor unit is further operative to ascertain and assign a value corresponding to the location and size of said characteristic of said tubular conduit.

35. The apparatus according to claim 1, wherein said value is representative of a location of said characterized changes.

36. The apparatus according to claim 1, wherein said value is representative of a size of said characterized changes.

37. A method for using a computer to detect, locate and characterize changes in a tubular conduit system within a living body for transferring fluids wherein said computer is operatively connected to a signal generator configured to transmit into said tubular conduit a probe signal that changes in response to encountering changes in said tubular conduit system and a signal sensor operative to receive said probe signal following transmission into said tubular conduit system, said method comprising the steps of:

receiving said probe signal following transmission through said tubular conduit system;

identifying changes in said probe signal;

detecting characteristics of said tubular conduit system, said characteristics of said tubular conduit system being derived from changes in said probe signal; and

recognizing and assigning a value of said characteristic of said tubular conduit said system.

38. The method according to claim 37 including the steps of ascertaining and assigning a value corresponding to the location and size of said characteristic of said tubular conduit.

39. The method according to claim 37 further including selecting a process from a plurality of processes identifying changes in said probe signal and therefrom detecting changes in said tubular conduit system.

40. The method according to claim 37, wherein said tubular conduit system is a blood vessel system, said method further including detecting changes in arterial characteristics.

41. The method according to claim 40 including detecting aneurysms.

42. The method according to claim 40 including detecting stenosis.

43. The method according to claim 40 including detecting arterial occlusions.

44. The method according to claim 40 wherein said signal generator is a pressure signal generator, and said signal sensor is a pressure signal sensor;

said method including receiving a heart beat signal; and

synchronizing receipt of said probe signal with said heart beat signal.

45. The method according to claim 40 wherein said probe signal is a plurality of discrete signals;

said method including sampling said discrete signals and receiving pressure wave velocity data.

46. The method according to claim 45 including the steps of performing a single pressure function using said discrete signals and said pressure wave velocity data.

47. The method of claim 46 wherein said performing step includes the step of calculating an allpass value and a cepstrum value from said minimum phase component.

48. The method of claim 46 wherein said performing step includes the step of separating a regular part and a singular part of said cepstrum value, where said singular part and said regular part form said pressure wave.

49. The method of claim 46 wherein said performing step includes the step of calculating an exponential function of singular part.

50. The method of claim 46 wherein said performing step includes the step of evaluating a second peak time delay with respect to a forward found in said pressure signal.

51. The method of claim 46 wherein said performing step includes the step of evaluating a coefficient by calculation of a second peak amplitude to determine an arterial characteristic.

52. The method of claim 46 wherein said performing step includes the step of evaluating a location of said arterial characteristic.

53. The method of claim 40 wherein said signal sensor includes two sensing transducers disposed in spaced apart relation, said method includes the step of receiving a forward pressure wave signal from a first transducer and a probe signal represented by a plurality of discrete signals sampled overtime.

54. The method according to claim 53 further including the step of calculating a pressure wave velocity from a pressure wave sensed by said first and second transducers.

55. The method according to claim 54 further including the step of performing a dual pressure function.

56. The method of claim 55 wherein said performing step includes the step of calculating an allpass component and cepstrum component of a minimum phase component of said forward pressure wave signal received from said signal sensor.

57. The method of claim 46 wherein said performing step includes the step of applying an inverse filtering of said forward pressure wave signal.

58. The method of claim 56 wherein said performing step includes the step of applying smoothing by a B-spline function.

59. The method of claim 56 wherein said performing step includes the step of detecting a forward peak location by a global maximum calculation.

60. The method of claim 56 wherein said performing step includes the step of receiving a threshold value.

61. The method of claim 56 wherein said performing step includes the step of detecting a second peak location by comparison with said threshold, where said threshold is derived from a forward peak maximum value and minimum size of a characteristic.

62. The method of claim 56 wherein said performing step includes the step of evaluating a second peak time delay with respect to said forward peak.

63. The method of claim 56 wherein said performing step includes the step of evaluating a reflection coefficient by calculating a forward and reflected peak area.

64. The method of claim 56 wherein said performing step includes the step of evaluating a location of said characteristic.

65. The method of claim 56 wherein said performing step includes the step of calculating a pressure wave velocity from a pressure wave sensed by said first and second transducers.

66. The method according to claim 39 wherein said signal sensor is movable between at least two positions relative to said tubular conduit system, said method including the step of calculating a pressure wave velocity from signals received from said two positions.

67. The method according to claim 40 wherein said signal sensor is a flow sensor.

68. The method according to claim 40 wherein said signal sensor is adapted to measure change in a cross-sectional diameter of said tubular conduit.

69. The method according to claim 40 wherein said signal sensor is an intravascular flow sensor.

70. The method according to claim 40 wherein said signal sensor is an external imaging device.

71. The method according to claim 40 wherein said arterial characteristics are selected from the group consisting of aneurysms, stenosis, occlusion, dissection and stent multipositioning.