Acoustic detection of vascular conditions

• US 6,780,159 B2
• Filed: 01/15/2002
• Issued: 08/24/2004
• Est. Priority Date: 01/16/2001
• Status: Active Grant

• Current Assignee: Biomedical Acoustic Research Corporation
• Original Assignee: Biomedical Acoustic Research Corporation
• Inventors: Sandler, Richard H., Mansy, Hussein A.
• Primary Examiner(s): Nasser, Robert L.
• Application Number:
  US10/046,863
• Publication Number:
  US 20020099286A1
• Time in Patent Office: 952 Days
• Field of Search: 600/505, 600/586, 600/587, 600/528, 600/504
• US Class Current: 600/504
• CPC Class Codes: A61B 2562/0204 Acoustic sensors
• CPC Class Codes: A61B 5/026 Measuring blood flow A61B3/1233, A61B3/1241 take precedence
• CPC Class Codes: A61B 5/6824 Arm or wrist
• CPC Class Codes: A61B 7/00 Instruments for auscultation
• CPC Class Codes: A61B 7/026 comprising more than one sound collector
• CPC Class Codes: A61M 1/3656 Monitoring patency or flow at connection sites; Detecting disconnections
• CPC Class Codes: A61M 2205/3375 Acoustical, e.g. ultrasonic, measuring means

Abstract

A system and method of detecting a vascular condition within a body receives vibrations emitted in response to blood flowing through a vascular structure within the body and converts the received vibrations into vibration information. The system and method generates spectral information from the vibration information, calculates a spectral parameter based on the spectral information and detects the vascular condition based on the spectral parameter.

Claims

1. A method of detecting a vascular condition, the method comprising:

receiving sound information associated with blood flowing through a vascular structure;

converting the sound information into temporal data associated with a plurality of cardiac cycles;

averaging the temporal data to form a set of average data; and

detecting the vascular condition based on a difference between the temporal data and the set of average data.

2. The method of claim 1, wherein receiving the sound information includes receiving a signal from at least one vibration sensor.

3. The method of claim 1, wherein receiving the sound information includes receiving sound emitted in response to the blood flowing through one of a shunt, a vein and an artery.

4. The method of claim 1, further comprising generating spectral information associated with the difference between the temporal data and the set of average data.

5. The method of claim 4, wherein detecting the vascular condition includes detecting the vascular condition based on a spectral parameter associated with the spectral information.

6. The method of claim 5, wherein detecting the vascular condition based on the spectral parameter includes comparing the spectral parameter to a reference value.

7. The method of claim 6, wherein comparing the spectral parameter to the reference value includes comparing the spectral parameter to a value indicative of an abnormal vascular condition.

8. The method of claim 7, wherein comparing the spectral parameter to the value indicative of the abnormal vascular condition includes comparing the spectral parameter to a value associated with at least one of a vascular patency, a vascular occlusion and a vascular stenosis.

9. The method of claim 1, wherein converting the sound information into the temporal data associated with the plurality of cardiac cycles includes aligning groups of data, each of which is associated with one of the plurality of cardiac cycles.

10. The method of claim 1, wherein averaging the temporal data to form the set of average data includes identifying groups of temporal data, each of which is associated with one of the plurality of cardiac cycles, and averaging the groups of temporal data to generate data representative of an average cardiac cycle.

11. A method of detecting a vascular condition, the method comprising:

receiving vibrations emitted in response to blood flowing through a vascular structure;

converting the received vibrations into vibration information;

generating spectral information from the vibration information;

calculating a spectral parameter based on the spectral information, wherein calculating the spectral parameter based on the spectral information includes calculating a time dependent amplitude signal and calculating an amplitude ratio based on the time dependent amplitude signal; and

detecting the vascular condition based on the spectral parameter.

12. The method of claim 11, further comprising calculating the spectral parameter based on a plurality of energy values associated with a respective plurality of frequency bands within the spectral information and calculating an energy ratio based on the plurality of energy values.

13. A method of detecting a vascular condition, the method comprising:

receiving vibrations emitted in response to blood flowing through a vascular structure;

converting the received vibrations into vibration information;

generating spectral information from the vibration information, wherein generating spectral information from the vibration information includes identifying groups of temporal data, each of which is associated with one of a plurality of cardiac cycles, and averaging the groups of temporal data to generate an average time domain signal representative of an average cardiac cycle, and wherein generating spectral information from the vibration information further includes subtracting the average time domain signal from each of the groups of temporal data;

calculating a spectral parameter based on the spectral information; and

detecting the vascular condition based on the spectral parameter.

14. A system for detecting a vascular condition body, the system comprising:

a memory; and

a processor communicatively coupled to the memory, wherein the processor is programmed to receive sound information, wherein the processor is programmed to convert the sound information into temporal data associated with a plurality of cardiac cycles, wherein the processor is programmed to average the temporal data to form a set of average data, and wherein the processor is programmed to detect the vascular condition based on a difference between the temporal data and the set of average data.

15. The system of claim 14, further comprising at least one vibration sensor operatively coupled to the processor and configured to detect the sound information.

16. The system of claim 15, wherein the vibration sensor is adapted to detect vibrations associated with blood flowing through a vascular structure.

17. The system of claim 16, wherein the vascular structure is one of a shunt, an artery and a vein.

18. The system of claim 14, wherein the processor is further programmed to generate spectral information associated with the difference between the temporal data and the set of average data.

19. The system of claim 18, wherein the processor is further programmed to detect the vascular condition based on a spectral parameter associated with the spectral information.

20. The system of claim 19, wherein the processor is further programmed to compare the spectral parameter to a reference value.

21. The system of claim 19, wherein the processor is further programmed to compare the spectral parameter to a value indicative of an abnormal vascular condition.

22. The system of claim 21, wherein the the abnormal vascular condition is associated with at least one of a vascular patency, a vascular occlusion and a vascular stenosis.

23. The system of claim 14, wherein the processor is further programmed to convert the sound information into the temporal data by aligning groups of data, each of which is associated with one of the plurality of cardiac cycles.

24. The system of claim 14, wherein the processor is further programmed to average the temporal data to form the set of average data by identifying groups of temporal data, each of which is associated with one of the plurality of cardiac cycles, and averaging the groups of temporal data to generate an average time domain signal representative of an average cardiac cycle.

26. The system of claim 19, wherein the processor is further programmed to calculate the spectral parameter based on a plurality of energy values associated with a respective plurality of frequency bands within the spectral information and to calculate an energy ratio based on the plurality of energy values.

25. A system for detecting a vascular condition, the system comprising:

a memory; and

a processor communicatively coupled to the memory, wherein the processor is programmed to receive vibration information, wherein the processor is programmed to generate spectral information from the vibration information and to calculate a spectral parameter based on the spectral information, and wherein the processor is programmed to detect the vascular condition based on the spectral parameter, and wherein the processor is further programmed to calculate a time dependent amplitude signal and to calculate an amplitude ratio based on the time dependent amplitude signal.

27. A system for detecting a vascular condition, the system comprising:

a memory; and

a processor communicatively coupled to the memory, wherein the processor is adapted to receive vibration information, wherein the processor is programmed to generate spectral information from the vibration information and to calculate a spectral parameter based on the spectral information, wherein the processor is programmed to detect the vascular condition based on the spectral parameter and to identify groups of temporal data, each of which is associated with one of a plurality of cardiac cycles, and to average the groups of temporal data to generate an average time domain signal representative of an average cardiac cycle, and wherein the processor is further programmed to subtract the average time domain signal from each of the groups of temporal data.

28. A machine readable medium having instructions stored thereon that, when executed, cause a machine to:

receive sound information associated with a vascular condition;

convert the sound information into temporal data associated with a plurality of cardiac cycles;

average the temporal data to form a set of average data; and

detect the vascular condition based on a difference between the temporal data and the set of average data.

29. The machine readable medium of claim 28, wherein the instructions, when executed, cause the machine to receive the sound information from a plurality of vibration sensors.

30. The machine readable medium of claim 28, wherein the instructions, when executed, cause the machine to generate spectral information associated with the difference between the temporal data and the set of average data.

31. The machine readable medium of claim 30, wherein the instructions, when executed, cause the machine to detect the vascular condition based on a spectral parameter associated with the spectral information.

32. The machine readable medium of claim 31, wherein the instructions, when executed, cause the machine to compare the spectral parameter to a reference value.

33. The machine readable medium of claim 32, wherein the reference value is associated with an abnormal vascular condition.

34. The machine readable medium of claim 33, wherein the the abnormal vascular condition includes at least one of a vascular patency, a vascular occlusion and a vascular stenosis.

35. The machine readable medium of claim 28, wherein the instructions, when executed, cause the machine to convert the sound information into the temporal data by aligning groups of data, each of which is associated with one of the plurality of cardiac cycle.

36. The machine readable medium of claim 28, wherein the instructions, when executed, cause the machine to identify groups of temporal data, each of which is associated with one of a plurality of the cardiac cycles, and to average the groups of temporal data to generate data representative of an average cardiac cycle.

37. A machine readable medium having instructions stored thereon that, when executed, cause a machine to:

receive vibration information associated with a vascular condition;

generate spectral information from the vibration information;

calculate a spectral parameter based on the spectral information by calculating a time dependent amplitude signal and calculating an amplitude ratio based on the time dependent amplitude signal; and

detect the vascular condition based on the spectral parameter.

38. The machine readable medium of claim 37, wherein the the instructions, when executed, cause the machine to calculate the spectral parameter by calculating a plurality of energy values associated with a respective plurality of frequency bands within the spectral information and calculating an energy ratio based on the plurality of energy values.

39. A machine readable medium having instructions stored thereon that, when executed, cause a machine to:

receive vibration information associated with a vascular condition;

generate spectral information from the vibration information;

calculate a spectral parameter based on the spectral information;

detect the vascular condition based on the spectral parameter; and

identify groups of temporal data, each of which is associated with one of a plurality of cardiac cycles, and to average the groups of temporal data to generate an average time domain signal representative of an average cardiac cycle and to subtract the average time domain signal from each of the groups of temporal data.