Method and apparatus for non-invasive detection and analysis of turbulent flow in a patient's blood vessels

• US 5,727,561 A
• Filed: 04/23/1996
• Issued: 03/17/1998
• Est. Priority Date: 04/23/1996
• Status: Expired due to Term

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: The United States of America As Represented By The Secretary of Agriculture
• Inventors: Owsley, Norman L.
• Primary Examiner(s): Kamm, William R.
• Assistant Examiner(s): EVANISKO, GEORGE ROBERT
• Application Number:
  US08/641,049
• Time in Patent Office: 693 Days
• Field of Search: 128/672, 128/687-691
• US Class Current: 600/504
• CPC Class Codes: A61B 7/00 Instruments for auscultation

Abstract

A method and apparatus for the diagnosis of pathological turbulent arteriallood flow in a patient includes energy wave detectors for sensing at a plurality of spaced positions on the patient forces generated by turbulent arterial blood flow. The detectors generate a plurality of space time signals that are arranged in a vectorized data structure. A processor converts the vectorized data structures into an output that indicates the form of the waves propagated from the site of the turbulent arterial blood flow, the location and spatial configuration of that site.

Claims

1. Apparatus for the diagnosis of pathologic turbulent arterial blood flow in a patient comprising:

wave sensing means positioned at a plurality of spaced sites on the patient for generating a corresponding plurality of space time signals responsive to energy waves propagated from a site of arterial blood flow;

interfacing means responsive to each of the space time signals from said wave sensing means for generating a vectorized data structure corresponding to the energy waves, said interfacing means including a frequency domain transform means for transforming desired portions of said plurality of said space time signals into a continuous sequence of time sampled sensor data; and

processing means responsive to the vectorized data structures from said interfacing means for generating a report signal indicating the temporal waveform of the energy wave propagating from the site of turbulent arterial blood flow, the location and spatial configuration of that site.

2. Apparatus as recited in claim 1 wherein said wave sensing means comprises a plurality of discrete auscultatory sensors.

3. Apparatus as recited in claim 2 wherein each of said auscultatory sensors is supported in a predetermined spaced relationship with others of said auscultatory sensors to define an array.

4. Apparatus as recited in claim 3 wherein the predetermined spaced relationship of adjacent ones of said auscultatory sensors is a specific distance that is less than the maximum speed of the wave front in the patient divided by twice the maximum frequency of the space time signals processed by said processing means.

5. Apparatus as recited in claim 1 wherein said interfacing means further comprises means for providing a cardiac timing signal and means for gating the generated plurality of space time signals to produce an array of time sampled data.

6. Apparatus for the diagnosis of pathologic turbulent arterial blood flow in a patient comprising:

wave sensing means positioned at a plurality of spaced sites on the patient for generating a corresponding plurality of space time signals responsive to energy waves propagated from a site of arterial blood flow;

interfacing means responsive to each of the space time signals from said wave sensing means for generating a vectorized data structure corresponding to the energy waves, said interfacing means including;

a means for providing a cardiac timing signal;

a means for gating the generated plurality of space time signals to produce an array of time sampled data; and

a Fourier transform means for transforming desired portions of said plurality of said space time signals into a continuous sequence of time sampled sensor data; and

processing means responsive to the vectorized data structures from said interfacing means for generating a report signal indicating the temporal waveform of the energy wave propagating from the site of turbulent arterial blood flow, the location and spatial configuration of that site.

7. Apparatus as recited in claim 6 wherein said interfacing means includes means for producing a vectorized data structure in a frequency-time domain.

8. Apparatus as recited in claim 7 wherein said processing means includes means for estimating a cross-spectral density matrix from said vectorized data structure.

9. Apparatus as recited in claim 8 said processing means includes means for computing an eigenstructure from the estimated cross-spectral density to determine dominant modal wave forms.

10. Apparatus as recited in claim 9 wherein said processing means generates an imaging signal from the eigenstructure and an imaging vector for the patient.

11. A method for providing diagnostic information with respect to arterial blood flow in a patient comprising the steps of:

sensing at a plurality of spaced locations on the patient over a time interval, energy waves generated by a turbulent blood flow volume as the energy waves propagate through the patient'"'"'s tissue, said energy waves producing corresponding signals;

selecting said signals for at least one time interval;

generating vectorized data structures of said signals corresponding to the energy waves sensed at the plurality of locations at the selected time intervals by said sensing step, said generating step including transforming said selected signals to the frequency domain and producing a continuous sequence of time sampled sensor data for use as said vectorized data structure; and

processing each of the data structures to produce a reporting signal corresponding to the patient'"'"'s tissue through which the energy waves pass to the spaced locations to indicate the temporal waveform, location and spatial configuration of the turbulent flow volume.

12. A method as recited in claim 11 wherein said sensing step comprises providing an array of spaced detectors for sensing the energy waves, placing the array on the patient with the detectors at the plurality of locations and generating signals corresponding to the energy waves.

13. A method as recited in claim 11 wherein said generating step comprises temporally gating the signals corresponding to the energy waves sensed at the plurality of locations at the selected time intervals, Fourier transforming the temporally gated signal and arranging the transformed signals in the vectorized data structure.

14. A method as recited in claim 13 wherein said processing step further includes computing a low-rank cross-spectral density matrix and a low-rank cross-spectral density inverse matrix from said vectorized data structure, defining an imaging vector corresponding to the patient'"'"'s tissue, and determining imaging signals from the imaging vector and the cross-spectral density matrix and its inverse.

15. A method as recited in claim 14 wherein said processing step further includes selecting a spatial imaging point, employing the defined imaging vector for the selected point, inverse Fourier transforming the vectorized data structure including the selected point and spectrum analyzing the inverse Fourier transformed data structure to produce a time domain report signal.

16. A method as recited in claim 11 wherein said processing step further includes computing a low-rank cross-spectral density matrix and a low-rank cross-spectral density inverse matrix from said vectorized data structure, defining an imaging vector corresponding to the patient'"'"'s tissue, and determining imaging signals from the imaging vector and the cross-spectral density matrix and its inverse.

17. A method as recited in claim 16 wherein said processing step further includes selecting a spatial imaging point, employing the defined imaging vector for the selected point, inverse Fourier transforming the vectorized data structure including the selected point and spectrum analyzing the inversely transformed data structure to produce a report signal.

18. A method as recited in claim 16 wherein said processing step further includes selecting a spatial imaging volume, employing the defined imaging vectors for the selected volume, inverse Fourier transforming the vectorized data structure including the selected volume, and spectrum analyzing the inversely transformed data structure to produce a report signal.

19. A method for providing diagnostic information with respect to arterial blood flow in a patient comprising the steps of:

sensing at a plurality of spaced locations on the patient over a time interval, energy waves generated by a turbulent blood flow volume as the energy waves propagate through the patient'"'"'s tissue said energy waves producing corresponding signals;

selecting said signals for at least one time interval;

generating vectorized data structures of said signals corresponding to the energy waves sensed at the plurality of locations at the selected time intervals by said sensing step, said generating step comprising temporally gating the signals corresponding to the energy waves sensed at the plurality of locations at the selected time intervals, Fourier transforming the temporally gated signal and arranging the transformed signals in the vectorized data structure; and

processing each of the data structures to produce a reporting signal corresponding to the patient'"'"'s tissue through which the energy waves pass to the spaced locations to indicate the temporal waveform, location and spatial configuration of the turbulent flow volume.

20. A method as recited in claim 19 wherein said processing step further includes computing a low-rank cross-spectral density matrix and a low-rank cross-spectral density inverse matrix from said vectorized data structure, defining an imaging vector corresponding to the patient'"'"'s tissue, and determining imaging signals from the imaging vector and the cross-spectral density matrix and its inverse.

21. A method as recited in claim 20 wherein said processing step further includes selecting a spatial imaging point, employing the defined imaging vector for the selected point, inverse Fourier transforming the vectorized data structure including the selected point, and spectrum analyzing the inverse Fourier transformed data structure to produce a time domain report signal.