JP2010029434A - Vasoconstriction level determination program, recording medium, information terminal device, vasoconstriction level determination system and vasoconstriction level determination method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vasoconstriction level determination program supporting a doctor's diagnosis by digitizing the constriction level of a shunt and at the same time being useful for a self check by a hemodialysis patient himself/herself. <P>SOLUTION: This program allows a computer to function: a pulse sound energy data acquisition procedure P1 for acquiring pulse sound energy data D1 from collected blood flow sound signals S; a frequency analysis procedure P2 executing the frequency analysis of the blood sound signals S for acquiring frequency spectrum envelope data D2; and a constriction level determination procedure P3 for determining the vasoconstriction level using the respective data D1 and D2 of the pulse sound energy and the frequency spectrum envelop acquired by the procedures P1 and P2, as parameters. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vascular stenosis degree determination program, a recording medium, an information terminal device, a vascular stenosis degree determination system, and a vascular stenosis degree determination method, and particularly supports a doctor's diagnosis by quantifying the stenosis degree of a shunt, The present invention relates to a vascular stenosis degree determination program, a recording medium, an information terminal device, a vascular stenosis degree determination system, and a vascular stenosis degree determination method that can be used for self-examination by hemodialysis patients themselves.

  When performing artificial dialysis of blood, in order to circulate a large amount of blood outside the body, it is necessary to create a bypass of a blood vessel called an “shunt” (see FIG. 8) by an anastomosis between an artery and a vein.

  When this shunt stenosis has a serious effect on hemodialysis patients, a specialist auscultates the sound of the blood flow flowing through the shunt, that is, the shunt sound, and diagnoses the shunt stenosis by experience. Furthermore, when examining a shunt in detail, it is highly dependent on the skill and experience of a doctor for diagnosis and inspection, such as using angiographic photographs.

  Conventionally, technical proposals have also been made regarding shunt sound processing and handling techniques. Patent Document 1 listed later installs a shunt sound acquisition device at an arbitrary position of the extracorporeal circulation blood circuit for the purpose of obtaining an accurate shunt sound, thereby converting vibration of the blood circuit caused by the shunt sound into an electrical signal. The frequency analysis is performed at arbitrary time intervals, the frequency band in which the frequency component of the shunt sound exists is extracted, the sound pressure sum of the band is calculated, and the sound pressure sum exceeding the predetermined set value is 1 pulse. The method of detecting it as a pulse of this is disclosed.

Japanese Patent Laying-Open No. 2005-328941 “Shunt Sound Acquisition Method and Device, Pulse Measurement Method Using the Shunt Sound and Device”

  Now, there is a problem in the conventional shunt sound measurement including the above-mentioned patent document. As mentioned above, the diagnosis of the degree of stenosis of the shunt must be relied on by auscultation of shunt sounds by experienced specialists, and detailed examination and diagnosis require more skill and experience of the doctor. is there. It would be convenient if judgment and examination of the degree of shunt stenosis, which has a significant impact on hemodialysis patients, can be easily performed by non-experts or even patients themselves.

  Therefore, the problem to be solved by the present invention is that, except for the above-mentioned problems of the prior art, the diagnosis of the doctor is supported by quantifying the degree of stenosis of the shunt, and at the same time, it is useful for self-examination by the hemodialysis patient itself. An object is to provide a vascular stenosis degree determination program, a recording medium, an information terminal device, a vascular stenosis degree determination system, and a vascular stenosis degree determination method.

  The inventor of the present application has studied the above problems. First, we tried to analyze the frequency characteristics of shunt sounds collected by microphones using a frequency analysis method using Fourier transform. However, with this method, the frequency characteristics are discrete, and it has been found that it is extremely difficult to determine whether or not there is stenosis.

  Therefore, the shunt sound and shunt vibration (hereinafter, included in the shunt sound) data is processed using a linear prediction method with smooth frequency characteristics and a frequency analysis method using the cepstrum method to determine the degree of stenosis of the shunt. Focusing on the fact that the determination of the presence or absence of stenosis is facilitated by digitization, the present invention has been completed. That is, the invention claimed in the present application, or at least the disclosed invention, as means for solving the above-described problems is as follows.

(1) A blood vessel stenosis degree determination program that can be executed by a computer or other information terminal device,
Pulse sound energy data acquisition procedure for obtaining pulse sound energy data from collected blood flow sound signals;
Frequency analysis processing procedure for obtaining a frequency spectrum envelope by performing frequency analysis processing on the blood flow sound signal;
Vessel stenosis that causes a computer or other information terminal device to function as a stenosis degree determination procedure for determining the degree of stenosis of a blood vessel using each data of pulse sound energy and frequency spectrum envelope obtained by these procedures as parameters Degree determination program.

    (2) The stenosis degree determination procedure is a procedure for outputting a calculation result by inputting actual data based on a predetermined calculation method using predetermined data of the pulse sound energy and frequency spectrum envelope as parameters. And the calculation method is associated with the actual degree of stenosis, according to (1).

(3) The blood vessel stenosis degree determination program according to (2), wherein the calculation method is a method shown in steps A to D below.
Step A: From the envelope of the frequency spectrum, in order of increasing peak,
The maximum peak value and the related frequency, the second peak value and the related frequency, ..., the kth peak value and the related frequency are obtained,
Step B: A vector v having components of pulse energy, maximum peak value, maximum peak frequency, second peak value, second peak frequency,..., K-th peak value, and k-th peak frequency is generated. ,
Step C: Each function related to the vascular stenosis degree determination step by inputting the vector v to the function f created in advance by the same number n as the determination stage number n of the vascular stenosis degree determination using the vector v as an argument. Stage R1 = function f1 (v)
Stage R2 = function f2 (v)
...
Stage Rn = function fn (v) is obtained,
Step D:
The stage having the maximum value among {stage R1, stage R2,..., Stage Rn} is the stage where the degree of vascular stenosis is determined.

(4) The blood vessel stenosis degree determination program according to (3), wherein the calculation method is performed in a neural network having the function as a component.
(5) The stenosis degree determination program according to any one of (1) to (4), wherein the stenosis degree determination procedure determines a stenosis degree of a blood vessel in three or more stages.

    (6) In the frequency analysis processing procedure, at least one of an LPC (Linear Predictive Coating) analysis method and a cepstrum method is used to obtain a frequency spectrum envelope. (1) to (5) The vascular stenosis degree determination program according to any one of the above.

    (7) Prior to each of the procedures, an initial setting procedure for determining the degree of vascular stenosis based on the collected blood flow sound signal is provided, and the initial setting procedure includes processing conditions in the frequency analysis processing procedure. The blood vessel stenosis degree determination program according to any one of (1) to (6), characterized in that a setting is included.

(8) The blood vessel stenosis degree determination program according to (7), wherein the initial setting procedure includes setting of the collection condition of the blood flow sound.
(9) The blood vessel stenosis degree determination program according to any one of (1) to (8), wherein the blood flow sound signal is a shunt sound signal and is used for determination of a shunt stenosis degree.

(10) A recording medium readable by a computer or other information terminal device on which the blood vessel stenosis degree determination program according to any one of (1) to (9) is recorded.
(11) The blood vessel stenosis degree determination program according to any one of (1) to (9) is stored, or the program can be executed, and a display unit for displaying the blood vessel stenosis degree determination result is provided. A computer or other information terminal device.

(12) The computer or other information terminal device according to (11), wherein waveform data of the pulse sound energy can be displayed on the display unit.
(13) An electronic stethoscope for collecting the blood flow sound signal is attached, and the collection portion of the electronic stethoscope is formed to be narrow enough to obtain the blood flow sound signal. The computer or other information terminal device according to (11) or (12).

(14) Pulse sound processing means for obtaining pulse sound energy data from the collected blood flow sound signal, and frequency analysis processing means for obtaining a frequency spectrum envelope by performing frequency analysis processing on the blood flow sound signal And a stenosis degree determination system including stenosis degree determination means for determining the degree of stenosis of the blood vessel using each parameter of pulse sound energy and frequency spectrum envelope obtained by each processing means as parameters. .
(15) A blood vessel stenosis degree determination method that can be executed by a computer or other information terminal device, the method comprising:
Pulse sound energy data acquisition procedure for obtaining pulse sound energy data from collected blood flow sound signals;
Frequency analysis processing procedure for obtaining a frequency spectrum envelope by performing frequency analysis processing on the blood flow sound signal;
A stenosis degree determination method comprising: a stenosis degree determination procedure for determining a stenosis degree of a blood vessel by using each data of pulse sound energy and frequency spectrum envelope obtained by each procedure as parameters.

(16) The stenosis degree determination procedure is a procedure for outputting a calculation result by substituting these actual data based on a certain calculation method using each data of pulse sound energy and frequency spectrum envelope as parameters. The method for determining the degree of vascular stenosis according to (15), wherein the calculation method is associated with the actual degree of stenosis and is the method shown in steps A to D below.
Step A: From the envelope of the frequency spectrum, in order of increasing peak,
The maximum peak value and the related frequency, the second peak value and the related frequency, ..., the kth peak value and the related frequency are obtained,
Step B: A vector v having components of pulse energy, maximum peak value, maximum peak frequency, second peak value, second peak frequency,..., K-th peak value, and k-th peak frequency is generated. ,
Step C: Each function related to the vascular stenosis degree determination step by inputting the vector v to the function f created in advance by the same number n as the determination stage number n of the vascular stenosis degree determination using the vector v as an argument. Stage R1 = function f1 (v)
Stage R2 = function f2 (v)
...
Stage Rn = function fn (v) is obtained,
Step D:
The stage having the maximum value among {stage R1, stage R2,..., Stage Rn} is the stage where the degree of vascular stenosis is determined.

  In other words, in the best mode of the present invention, the frequency analysis method using the linear prediction method or the cepstrum method is used, and the stenosis degree of the shunt is quantified by comparing the frequency characteristics, so that the multistage determination of the stenosis degree can be performed. It is.

  Since the blood vessel stenosis degree determination program, recording medium, information terminal device, vascular stenosis degree determination system, and vascular stenosis degree determination method of the present invention are configured as described above, according to this, the stenosis degree of the shunt is quantified. Therefore, it is possible to support a doctor's diagnosis, and at the same time, it can be used for self-examination by hemodialysis patients themselves.

  That is, according to the present invention, the frequency characteristic of the shunt sound can be analyzed by the linear prediction method or the cepstrum method, and the stenosis degree can be converted into a numerical value, so that the stenosis degree can be divided into a plurality of patterns. Thereby, it can be used for daily management not only by doctors but also by hemodialysis patients themselves.

Hereinafter, the present invention will be described in more detail with reference to the drawings.
FIG. 1 is a flowchart showing the configuration of the blood vessel stenosis degree determination program of the present invention. As shown in the figure, this program is a program that can be executed by a computer or other information terminal device, and a pulse sound energy data acquisition procedure P1 for obtaining pulse sound energy data D1 from the collected blood flow sound signal S. A frequency analysis processing procedure P2 for obtaining a frequency spectrum envelope data D2 by performing a frequency analysis process on the blood flow sound signal S, and the pulse sound energy data D1 and the frequency spectrum envelope obtained by the procedures P1 and P2. The program comprises a stenosis degree determination procedure P3 for determining the degree of stenosis of the blood vessel using the data D2 as a parameter and obtaining a determination result R, and is a program for causing these procedures to function on a computer or other information terminal device. Is the main configuration.

  In the figure, the stenosis degree determination procedure P3 is a procedure for outputting a calculation result by inputting these actual data based on a certain calculation method using the pulse sound energy data D1 and the frequency spectrum envelope data D2 as parameters. is there. The calculation method is configured in association with the actual degree of stenosis.

With this configuration, the program of the present invention
First, in the pulse sound energy data acquisition procedure P1, pulse sound energy data D1 is obtained from the collected blood flow sound signal S, and in the frequency analysis processing procedure P2, the blood flow sound signal S is subjected to frequency analysis processing. The frequency spectrum envelope data D2 is obtained, and in the stenosis degree determination procedure P3, the pulse sound energy data D1 and the frequency spectrum envelope data D2 obtained by the procedures P1 and P2 are used as parameters to determine the degree of stenosis of the blood vessel. Thus, the procedure of obtaining the determination result R is caused to function in a computer or other information terminal device. Therefore, these procedures are executed in the computer or other information terminal device.

In the stenosis degree determination procedure P3, based on a certain calculation method using the pulse sound energy data D1 and the frequency spectrum envelope data D2 as parameters, a calculation result is output by inputting these actual data.

The calculation method according to the stenosis degree determination procedure P3 of the program of the present invention is configured in association with the actual stenosis degree. Specifically, the following steps A to D can be executed in order. That is,
Step A starts from the envelope data D2 of the frequency spectrum in descending order of peak.
In this step, the maximum peak value and the related frequency, the second peak value and the related frequency,..., The k th peak value and the related frequency are obtained.

  Step B is the maximum peak value, the maximum peak frequency, the second peak value, the second peak frequency,..., The k-th peak value, from the pulse sound energy data D1 and the frequency spectrum envelope data D2. This is a step in which a vector v having the frequency of k peak as a component is created.

  On the other hand, the function f is prepared and prepared in advance by the same number n as the determination stage number n of the vascular stenosis degree determination using the vector v generated in step B as an argument.

Then, in step C, the vector v is input to these functions f, and the values of the respective functions related to the vascular stenosis degree determination stage are as follows:
Stage R1 = function f1 (v), stage R2 = function f2 (v),... Stage Rn = function fn (v)

  Finally, step D is a step in which the stage having the maximum value among {stage R1, stage R2,..., Stage Rn} is the stage where the degree of vascular stenosis is determined.

The calculation method according to the stenosis degree determination procedure P3 of the vascular stenosis degree determination program of the present invention can be configured specifically in a neural network. Hereinafter, a method for obtaining a determination rank indicating the degree of shunt stenosis from the frequency spectrum envelope data of the shunt sound will be described. First, a nonlinear element having an input / output relationship as shown in Equation 1 is prepared.
2A is a conceptual diagram showing a nonlinear element having an input / output relationship according to Equation 1. FIG.

Next, a neural network having a three-layer structure is prepared in which I, J, and K nonlinear elements are prepared for the input layer, the intermediate layer, and the output layer, respectively. The threshold values of the intermediate layer and the output layer are θ1j (j = 1, 2,..., J) and θ2k (k = 1, 2,..., K), respectively. In order to handle the threshold value in the same way as the weighting factor, an input whose input value is always 1 and whose weighting factors are −θ1j and −θ2k is added. Then, the relationship between the input xi and the intermediate output yj, and the intermediate output yj and the final output zk is expressed by Equation 2.
FIG. 2B is a conceptual diagram showing a three-layered neural network whose relationship is expressed by Equation 2.

  Finally, when a data set, that is, a vector extracted from the shunt sound frequency spectrum envelope is input to the neural network, the most similar shunt sound frequency spectrum pattern can be output. In the stenosis degree determination procedure, the number of stages for determining the degree of stenosis of the blood vessel is not particularly limited, but it is desirable that the determination includes an intermediate stage. In other words, it is desirable that the degree of stenosis of a blood vessel such as a shunt can be classified into a plurality of stages of three or more stages by quantification, not just two stages with and without stenosis.

  FIG. 3 is a graph showing a frequency analysis method used in the frequency analysis processing procedure of the program of the present invention. The upper graph shows the shunt sound waveform, the middle graph shows a partially enlarged waveform of the upper shunt sound, and the lower graph shows the frequency characteristics of the waveform obtained by the Fourier transform method, LPC (linear predictive coating) method, and cepstrum method. It is a graph to show. As shown in the figure, the LPC analysis method and the cepstrum method are easier to analyze than the Fourier transform method. In the program of the present invention, frequency spectrum envelope data is obtained using at least one of the LPC analysis method and the cepstrum method. I will do it.

  FIG. 4 is a flowchart showing another configuration of the blood vessel stenosis degree determination program of the present invention. As shown in the figure, in the program of the present invention, an initial setting procedure P0 for determining the degree of vascular stenosis based on the collected blood flow sound signal S is provided prior to the above-described procedures P1, P2 and P3. The procedure P0 can be configured to include setting of processing conditions in the frequency analysis processing procedure P2. Furthermore, the initial setting procedure P0 can be configured to include the setting of blood flow sound collection conditions.

  The blood vessel stenosis degree determination program of the present invention can be widely used for blood vessel stenosis degree determination, but as described above, it is particularly effective for determination of shunts. That is, this program is extremely useful as a program that can determine the degree of shunt stenosis based on a shunt sound signal.

  The blood vessel stenosis degree determination program of the present invention can be provided using an appropriate medium such as a communication line such as the Internet, a recording medium readable by a computer or other information terminal device. Of course, a form of a dedicated or non-dedicated computer or other information terminal device storing the vascular stenosis degree determination program of the present invention is also within the scope of the present invention.

  In addition, it is convenient if such a computer or other information terminal device is provided with a display unit for displaying a result of determining the degree of vascular stenosis. In that case, it is more convenient if the waveform data of the pulse sound energy can be displayed on the display unit. For example, doctors or hemodialysis patients themselves can easily visually inspect the degree of stenosis of blood vessels such as shunts on a screen. It is convenient to set a pattern for judging the degree of stenosis so that it can be displayed.

  The computer or other information terminal device may further include an electronic stethoscope for collecting blood flow sound signals. The area of the collection portion of the electronic stethoscope may be as narrow as necessary to obtain a blood flow sound signal in order to increase the S / N ratio and efficiently collect blood flow sound. In other words, it is a pinpoint sound collection directivity.

Based on the vascular stenosis degree determination program of the present invention described above, a vascular stenosis degree determination system can be configured. The system includes a pulse sound processing means for obtaining data of the pulse sound energy from the collected blood flow sound signal, and a frequency analysis processing means for obtaining a frequency spectrum envelope by performing frequency analysis processing on the blood flow sound signal. And stenosis degree determination means for determining the degree of stenosis of the blood vessel using the pulse sound energy and frequency spectrum envelope data obtained by each processing means as parameters.
FIG. 5 is an explanatory diagram showing a configuration example of such a vascular stenosis degree determination system.

Hereinafter, although the example which constructed | assembled the shunt stenosis degree determination system is demonstrated as an Example of this invention, this invention is not limited to this Example.
<1 Achievement target>
1-1 A system that can classify and examine and determine the degree of stenosis of a shunt not only in two stages of presence / absence of stenosis but also in multiple stages of three or more stages.
1-2 Create a practical pattern that allows doctors and hemodialysis patients to visually check the degree of stenosis on the screen for each stage of stenosis degree determination.

<2 System configuration>
2-1 Shunt sound collection means Shunt sounds are collected with an electronic stethoscope.
The blood pumped out along with the heartbeat flows through the artery as a pulsation. When this pulsation passes through the constricted portion of the shunt, turbulence is generated, causing the blood vessel wall to vibrate. The vibration of the blood vessel wall is collected as a shunt sound by an electronic stethoscope.

2-2 Shunt Sound Analysis Program A shunt sound analysis program is created as a method for determining the degree of stenosis of the shunt portion for each stage division from the collected shunt sounds.
The input to the program is shunt sound data collected with an electronic stethoscope. This is processed by the LPC analysis method and / or the cepstrum analysis method, or both to obtain frequency spectrum envelope data as an output.

  In this program, the frequency spectrum envelope and the degree of stenosis were combined. This is a point not found in the prior art. As a result, the pattern of the frequency spectrum envelope and the stenosis degree of the shunt portion can be associated with each other, and the stenosis degree can be determined for each stage division.

2-3 Processing in the Program The entire shunt stenosis degree determination program is divided into four blocks, and the processing method is described for each block. Note that any of the following four patterns may be selected as the flow of each block.
(1)-(2)-(4),
(1)-(3)-(4),
(1)-(2)-(3)-(4) or (1)-(3)-(2)-(4)

(1) Initial setting block This block sets the time length of the shunt sound to be collected, the time length of the collected data used for analysis, and the like. Specific items to be set are as follows.
A Set the length of the shunt sound to be collected.
B) Set the length of shunt sound data used for frequency spectrum envelope. It may be different from the length of a.
C Set the start signal (mouse click or fixed time) for collecting shunt sound.
D) Set whether to collect the collected shunt sound data.
E Set up a program that removes circuit noise from electronic stethoscopes.
Sets the window frame, waveform size, position, pen color used for drawing, etc. when displaying the waveform of the sound waveform and frequency spectrum envelope on the display.
Set whether the frequency spectrum envelope to be used is based on the LPC analysis method, the cepstrum analysis method, or both.

(2) LPC analysis method block The input is shunt sound data collected by an electronic stethoscope, and the following processing is performed in the block.
Performs Fourier transform on the quantant sound data.
* Calculate the autocorrelation function using the result.
E Find the linear prediction coefficient.
Obtain the gain of the transfer function.
This analysis method finally provides a frequency spectrum envelope that changes slowly as an output. The frequency spectrum envelope has a characteristic that it is represented by a continuous curve. Therefore, partial enlargement can be performed, so that the determination of the degree of stenosis becomes easy.

(3) Cepstrum method block Input is shunt sound data collected as in (2), and the following processing is performed in the block.
Performs Fourier transform on the shunt sound data.
Obtain the absolute value of the frequency spectrum.
Then, the inverse Fourier transform is obtained.
Separate into finely changing parts and slowly changing parts.
The Fourier transform is performed again.

From the above processing, a frequency spectrum envelope that changes slowly as an output is obtained. The frequency spectrum envelope of this output has the characteristic of becoming discrete. Unlike the LPC analysis method shown in (2), there is no continuity, but there is an advantage that the calculation time is shorter than in (2).
FIG. 6 is a flowchart showing the main part of the configuration example of the shunt stenosis degree determination program according to the flow of blocks (1)-(3)-(4).

(4) Screen display block The shunt sound waveform and the frequency spectrum envelope are displayed on the set window frame in the set size, at the set position, in the set pen color, in an easy-to-understand manner on the display.

<3 System construction experiment plan>
Hereinafter, the plan of the construction experiment of the shunt stenosis degree determination system is described in four periods.
1st period Select a microphone to collect shunt sound efficiently and make a prototype of an amplifier circuit to expand the signal from the microphone.
Second period A matching test between the amplifier circuit and the frequency analysis program is repeatedly performed as preparation for establishing a reliable association between the frequency characteristics of the shunt sound and the degree of stenosis of the shunt.

Third period <1> Prototype a test system for the degree of shunt stenosis for field tests.
<2> A field test is carried out at the clinical site using the prototype inspection system. An outline of the field test will be described later.
In order to improve the reliability of the inspection system, the trial production of <1> and the implementation of <2> are repeated as necessary.

<3> Outline of field test <3> -1 Cooperation patients for collecting shunt sound Three hemodialysis patients who satisfy the following conditions are selected and fixed. Furthermore, one temporary cooperating patient is obtained.
3 patients tm (male): 3 months after vascular dilatation
on (male): 1-2 years after shunt surgery
ke (female): 4 to 5 years after shunt surgery One extraordinary patient
ks (male): Before and after vasodilatation <3> -2 Field test period December 22, 2007 to January 31, 2008

<3> -3 Field test frequency Regular collection: Once a week at 1pm on Thursday
Temporary collection: Saturday, December 22, 2007, 1 pm-
<3> -4 Location: Hospital in Goshogawara City, Aomori Prefecture <3> -5 Implementer and cooperator Takayuki Sasaki, Tom Medic Inc.

Fourth period <1> Frequency analysis of all shunt sound data collected from hemodialysis patients.
<2> Classify frequency characteristics into a plurality of frequency characteristic patterns.
<3> Several parameter values for classifying the frequency characteristic pattern obtained in <2> are described in the frequency analysis program, and the quality of the frequency characteristic pattern classification is repeatedly verified.

<4 Experimental results>
Achieved all the goals and fulfilled the research purpose. The results are described for each goal.
4-1 Goal “About the ability to inspect and determine the stenosis degree of the shunt not only in two stages of stenosis, but also in multiple stages of three or more stages by quantifying it” Five levels of stenosis of the shunt sound Could be classified.
FIG. 7 is an explanatory diagram showing the frequency characteristics and the ranking of the shunt stenosis degree in association with each other. In the drawing, the conceptual diagram of the degree of shunt stenosis shows the degree of stenosis depending on the state of adhesion of the stenosis substance in the blood vessel. The filled portion indicates the stenosis material. The frequency characteristic pattern is an envelope graph of a frequency characteristic based on a relative value where the maximum peak value is 1.

As shown in the figure, as the transition from rank A to rank E, the low frequency component decreases and the high frequency component increases. The cause is that the degree of stenosis of the shunt progresses and expands.
The parameters used for ranking are the total energy of the shunt sound, the energy of the pulse, and several frequencies that have large peaks in the frequency characteristic pattern. The conceptual diagram of the degree of shunt stenosis is predicted based on fluid dynamics.

4-2 Target to be achieved “To create a practical pattern that allows doctors and hemodialysis patients to visually check the degree of stenosis on the screen for each stage of stenosis degree determination” As shown in FIG. 7, it could be classified into five levels. Then, the degree of shunt stenosis could be associated with the frequency characteristic pattern in each. This achieved this goal.

<5 Summary>
5-1 Prototype of Test System By achieving the goal as described above, we were able to build a prototype of the numerical system for the degree of shunt stenosis in hemodialysis patients and the test system. Note that FIG. 5 is an example of such a system.

5-2 Pinpoint type electronic stethoscope In the process of this example, an electronic stethoscope in which a microphone and an amplifier circuit were integrated was prototyped. A feature of this electronic stethoscope is that the area of the shunt sound collection area is reduced. Thereby, the collection area of the shunt sound is narrowed, and it is possible to detect in which part a large stenosis has occurred. Since the area of the collected sound is smaller than that of a normal stethoscope, it can be said to be a pinpoint electronic stethoscope.

5-3 Development of frequency analysis program Two kinds of programs for frequency analysis of shunt sound have been developed. There are two types of programs: a program that can immediately analyze the frequency in real time on the spot, and a program that can analyze the frequency of shunt sound data collected at other locations at any time after the fact. Since the former program is easy to handle, it is effective for testing by hemodialysis patients themselves. In the latter case, shunt sound data can be recorded and stored as an electronic file, which can be used for data description in medical charts and future software development for frequency analysis.

  According to the blood vessel stenosis degree determination program, the recording medium, the information terminal device, the blood vessel stenosis degree determination system, and the blood vessel stenosis degree determination method of the present invention, the determination of the stenosis degree of the shunt and the determination of the degree of stenosis of the blood vessel including the examination, In the examination, it can support the diagnosis of a doctor and can also be used for self-examination by hemodialysis patients themselves. Thereby, it is useful for daily management not only by doctors but also by hemodialysis patients themselves, and is a highly useful invention in related industrial fields.

It is a flowchart which shows the structure of the blood vessel stenosis degree determination program of this invention. 3 is a conceptual diagram illustrating a nonlinear element having an input / output relationship according to Formula 1. FIG. 3 is a conceptual diagram illustrating a neural network having a three-layer structure whose relationship is expressed by Equation 2. FIG. It is a graph which shows the frequency analysis method used with the frequency analysis processing procedure of this invention program. It is a flowchart which shows another structure of the vascular stenosis degree determination program of this invention. It is explanatory drawing which shows the structural example of the vascular stenosis degree determination system of this invention. In an Example, it is a flowchart which shows the principal part of the shunt stenosis degree determination program structural example by the flow of block (1)-(3)-(4). It is explanatory drawing which showed the frequency characteristic and the ranking of the shunt stenosis degree corresponding to each other. It is explanatory drawing of a shunt.

Explanation of symbols

1 ...

Claims (16)

A blood vessel stenosis degree determination program executable by a computer or other information terminal device,
Pulse sound energy data acquisition procedure for obtaining pulse sound energy data from collected blood flow sound signals;
Frequency analysis processing procedure for obtaining a frequency spectrum envelope by performing frequency analysis processing on the blood flow sound signal;
Vessel stenosis that causes a computer or other information terminal device to function as a stenosis degree determination procedure for determining the degree of stenosis of a blood vessel using each data of pulse sound energy and frequency spectrum envelope obtained by these procedures as parameters Degree determination program. The stenosis degree determination procedure is a procedure for outputting a calculation result by inputting these actual data based on a predetermined calculation method using predetermined data of the pulse sound energy and frequency spectrum envelope as parameters, 2. The blood vessel stenosis degree determination program according to claim 1, wherein the calculation method is associated with an actual stenosis degree. The vascular stenosis degree determination program according to claim 2, wherein the calculation method is a method shown in steps A to D below.
Step A: From the envelope of the frequency spectrum, in order of increasing peak,
The maximum peak value and the related frequency, the second peak value and the related frequency, ..., the kth peak value and the related frequency are obtained,
Step B: A vector v having components of pulse energy, maximum peak value, maximum peak frequency, second peak value, second peak frequency,..., K-th peak value, and k-th peak frequency is generated. ,
Step C: Each function related to the vascular stenosis degree determination step by inputting the vector v to the function f created in advance by the same number n as the determination stage number n of the vascular stenosis degree determination using the vector v as an argument. Stage R1 = function f1 (v)
Stage R2 = function f2 (v)
...
Stage Rn = function fn (v) is obtained,
Step D:
The stage having the maximum value among {stage R1, stage R2,..., Stage Rn} is the stage where the degree of vascular stenosis is determined. The vascular stenosis degree determination program according to claim 3, wherein the calculation method is performed in a neural network having the function as a component. The stenosis degree determination program according to any one of claims 1 to 4, wherein, in the stenosis degree determination procedure, a stenosis degree of a blood vessel is determined in three or more stages. The frequency spectrum envelope is obtained by using at least one of an LPC (Linear Predictive Coating) analysis method and a cepstrum method in the frequency analysis processing procedure, according to any one of claims 1 to 5. Vascular stenosis degree judgment program. Prior to each procedure, an initial setting procedure for determining the degree of vascular stenosis based on the collected blood flow sound signal is provided, and the initial setting procedure includes setting of processing conditions in the frequency analysis processing procedure. The blood vessel stenosis degree determination program according to any one of claims 1 to 6, wherein The vascular stenosis degree determination program according to claim 7, wherein the initial setting procedure includes setting of a collecting condition of the blood flow sound. 9. The blood vessel stenosis degree determination program according to claim 1, wherein the blood flow sound signal is a shunt sound signal and is used for determination of a shunt stenosis degree. A recording medium readable by a computer or other information terminal device, on which the blood vessel stenosis degree determination program according to any one of claims 1 to 9 is recorded. 10. A computer or other computer that stores the blood vessel stenosis degree determination program according to claim 1 or that is capable of executing the program and that includes a display unit that displays the blood vessel stenosis degree determination result. Information terminal device. The computer or other information terminal device according to claim 11, wherein the display unit can also display waveform data of the pulse sound energy. An electronic stethoscope for collecting the blood flow sound signal is attached, and the collection portion of the electronic stethoscope is formed to be narrow enough to obtain the blood flow sound signal. The computer or other information terminal device according to claim 11 or 12. A pulse sound processing means for obtaining the pulse sound energy data from the collected blood flow sound signal, and a frequency analysis processing means for obtaining a frequency spectrum envelope by performing a frequency analysis process on the blood flow sound signal. Furthermore, a vascular stenosis degree determination system comprising stenosis degree determination means for determining the degree of stenosis of a blood vessel using each data of pulse sound energy and frequency spectrum envelope obtained by each processing means as parameters. A blood vessel stenosis degree determination method that can be executed by a computer or other information terminal device, the method comprising:
Pulse sound energy data acquisition procedure for obtaining pulse sound energy data from collected blood flow sound signals;
Frequency analysis processing procedure for obtaining a frequency spectrum envelope by performing frequency analysis processing on the blood flow sound signal;
A stenosis degree determination method comprising: a stenosis degree determination procedure for determining a stenosis degree of a blood vessel by using each data of pulse sound energy and frequency spectrum envelope obtained by each procedure as parameters. The stenosis degree determination procedure is a procedure for outputting a calculation result by substituting these actual data based on a constant calculation method using each data of pulse sound energy and frequency spectrum envelope as parameters. 16. The blood vessel stenosis degree determination method according to claim 15, wherein the method is associated with an actual degree of stenosis and is a method shown in steps A to D below.
Step A: From the envelope of the frequency spectrum, in order of increasing peak,
The maximum peak value and the related frequency, the second peak value and the related frequency, ..., the kth peak value and the related frequency are obtained,
Step B: A vector v having components of pulse energy, maximum peak value, maximum peak frequency, second peak value, second peak frequency,..., K-th peak value, and k-th peak frequency is generated. ,
Step C: Each function related to the vascular stenosis degree determination step by inputting the vector v to the function f created in advance by the same number n as the determination stage number n of the vascular stenosis degree determination using the vector v as an argument. Stage R1 = function f1 (v)
Stage R2 = function f2 (v)
...
Stage Rn = function fn (v) is obtained,
Step D:
The stage having the maximum value among {stage R1, stage R2,..., Stage Rn} is the stage where the degree of vascular stenosis is determined.