Method for detecting blockage in a fluid flow vessel

Abstract

A method for determining stenosis of the carotid artery in a human patient consisting of a first step of placing a sensing device comprising an array and three sensing elements onto the patient, wherein a first sensing element is placed near the heart and the two remaining sensing elements are placed adjacent to the carotid arteries; the sensing elements then measure sounds from each of the three sensing elements, resulting in sound from three channels. The sound is measured in analog and modified to digital format and then each of the three channels are analyzed before a power spectral density analysis is performed. The power spectral density graph reveals peaks that are not due to noise that are then analyzed to provide for a calculation of percent stenosis or complete occlusion of the carotid artery.

What is claimed is: 
     
         1 . A method for measuring sound from vortices in a carotid artery comprising:
 a. performing a first quality control procedure on at least two sensing elements, wherein said first quality control procedure is performed by playing a predetermined set of tones within a base unit, wherein said at least two sensing elements detect said set of tones and wherein said detected set of tones are compared to said predetermined set of tones, wherein the sensing elements are replaced if the comparison between said detected set of tones and said predetermined set of tones has a frequency variance of more than 10%;   b. performing a second quality control procedure on the at least two sensing elements, wherein said second quality control procedure is performed by detecting sounds of blood flow through the carotid artery and comparing said detected sounds to a predetermined sound signature, wherein the sensing element is repositioned if the detected sounds compared to the predetermined sound signature have a second frequency variance of more than 25%, wherein if the second frequency variance in the second quality control procedure is more than 100%, step (a) is repeated; and   c. detecting sounds generated by the vortices in the carotid artery for at least 30 seconds.   
     
     
         2 . The method of  claim 1  wherein the sounds detected from the vortices in the carotid artery are detected at between 40 Hz and 3,000 Hz. 
     
     
         3 . The method of  claim 1  wherein a further step (d) comprises eliminating sounds from the carotid artery that are outside of the range of 40 Hz to 3,000 Hz. 
     
     
         4 . The method of  claim 3  comprising a further step (e) comprising generating a power spectral density graph of the sounds from step (d). 
     
     
         5 . The method of  claim 1  comprising three sensor elements. 
     
     
         6 . The method of  claim 3  further comprising:
 e. downsampling the detected sounds from step (c) from analog to digital at a sampling rate of 20 kHz. 
 
     
     
         7 . The method of  claim 4  comprising a further step (f) of determining a percent stenosis from at least one peak in said power spectral density graph by calculating (1−f 1 /f 2 )×100. 
     
     
         8 . The method of  claim 1  wherein in step (a) if the comparison between said detected set of tones and said predetermined set of tones has a variance of more than 10% relative to frequency, then the sensing element needs to be replaced. 
     
     
         9 . The method of  claim 1  wherein in step (b) the sensing element is repositioned if the detected sounds compared to the predetermined sound signature have a variance of more than 25% relative to frequency. 
     
     
         10 . The method of  claim 8  wherein if the variance in the second quality control procedure is more than 100% relative to frequency, then step (a) is repeated. 
     
     
         11 . A method of detecting an occlusion in a fluid flow vessel comprising:
 a. placing a sensor pod having a listening device onto said fluid flow vessel;   b. detecting sounds passing through said fluid flow vessel;   c. performing wavelet analysis and removing low frequency sounds below 60 Hz;   d. performing Burg's Method, Welch's method, or both to denoise the data;   e. plotting a power spectral density plot of the frequency in the x-axis and intensity in the y-axis to generate at least two primary peaks in the power spectral density plot;   f. calculating the primary two peaks in the power spectral density plot; and   g. determining an occlusion percentage of the fluid flow vessel by calculating (1−f 1 /f 2 )×100.   
     
     
         12 . The method of  claim 11  comprising performing a first quality control procedure on said listening device before step (a) comprising:
 a1. playing a predetermined sound signature from a base; 
 a2. detecting said sound signature with said listening device; 
 a3. comparing said detected sound signature to the predetermined sound signature; and 
 a4. confirming proper function of the listening device if the difference between the frequency of the detected sound and the predetermined sound signature is 10% or less. 
 
     
     
         13 . The method of  claim 11  wherein the sounds detected passing through said fluid flow vessel are detected at between 40 Hz and 3,000 Hz. 
     
     
         14 . The method of  claim 11  wherein step (b) comprises eliminating sounds detected passing through said fluid flow vessel that are outside of the range of 40 Hz to 3,000 Hz. 
     
     
         15 . The method of  claim 11  further comprising downsampling the detected sounds from step (c) from analog to digital at a sampling rate of 20 kHz. 
     
     
         16 . A method of detecting an occlusion in an arterial vessel comprising:
 a. placing a sensor pod having a listening device on the skin of a patient adjacent to said arterial vessel;   b. detecting sounds passing through said arterial vessel;   c. performing wavelet analysis and removing low frequency sounds below 60 Hz;   d. performing Burg's Method, Welch's method, or both to denoise the data;   e. plotting a power spectral density plot of the frequency in the x-axis and intensity in the y-axis to generate at least two primary peaks in the power spectral density plot;   f. calculating the primary two peaks in the power spectral density plot; and   g. determining stenosis of the arterial vessel by calculating (1−f 1 /f 2 )×100.   
     
     
         17 . The method of  claim 16  wherein said arterial vessel is a carotid artery or a coronary artery. 
     
     
         18 . The method of  claim 16  comprising performing a first quality control procedure on said listening device before step (a) comprising:
 a1. playing a predetermined sound signature from a base; 
 a2. detecting said sound signature with said listening device; 
 a3. comparing said detected sound signature to the predetermined sound signature; 
 a4. confirming proper function of the listening device if the difference between the frequency of the detected sound and the predetermined sound signature is 10% or less; and 
 a5. performing a second quality control procedure on said listening device wherein said second quality control procedure is performed by detecting sounds of blood flow through the arterial vessel and comparing said detected sounds to a predetermined sound signature, wherein the listening device is repositioned if the detected sounds compared to the predetermined sound signature have a second frequency variance of more than 25%, wherein if the second frequency variance in the second quality control procedure is more than 100%, step (a) is repeated. 
 
     
     
         19 . The method of  claim 18  wherein detecting sounds of blood flow through the arterial vessel is detecting the detected sounds at a frequency of between 60 Hz and 260 Hz. 
     
     
         20 . The method of  claim 16  wherein the calculation of stenosis is a binary calculation of greater than or less than 50% stenosis.