JP2019187694A - Artery obstruction determination device, and program to function as artery obstruction determination device - Google Patents

Abstract

To provide an artery obstruction determination device capable of evaluating the obstruction or the like of a cerebral artery easily and quickly by using a pulse wave, and a program to function as an artery obstruction determination device.SOLUTION: An artery obstruction determination device includes measuring means 2 for measuring pulse wave data on the carotid artery of a human body, and determination means 4 for determining the presence or absence of the obstruction in the carotid artery and the cerebral artery branching from the carotid artery on the basis of the pulse wave data. The determination means 4 compares left pulse wave data on the left carotid artery with right pulse wave data on the right carotid artery, measured by the measuring means 2, and on the basis of the comparison result, determines the presence or absence of the obstruction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an arterial occlusion determination device and a program for causing it to function as an arterial occlusion determination device.

  Conventionally, for example, an arteriosclerosis evaluation apparatus described in Patent Document 1 is known as an apparatus for evaluating vascular functions such as arteriosclerosis. This device pays attention to the pulse wave transmitted through the artery and the blood flow velocity of the artery, and each amplitude intensity of the first waveform based on the blood flow velocity of the artery and the second waveform obtained by subtracting the first waveform from the pulse wave. The degree of arteriosclerosis is evaluated. Pulse waves vary greatly depending on their age, sex, health condition, etc., and it is generally difficult to set a common standard for determining a normal pulse wave. In this apparatus, the pulse wave is separated into an incident wave and a reflected wave using the arterial blood flow velocity, and the state of the blood vessel is determined.

  On the other hand, in an emergency medical field for a patient who has fallen due to cerebral infarction or the like, quick response to ischemic cerebrovascular disease, which is a disease in which brain cells fall into oxygen and nutrient deficiencies, is required. Since the main cause of ischemic cerebrovascular disease is stenosis or occlusion of the cerebral artery, an apparatus or method that can easily and quickly evaluate occlusion of the cerebral artery or the like has been desired.

Japanese Patent No. 5016717

  In view of such a conventional situation, an object of the present invention is to provide an arterial occlusion determination device that can easily and quickly evaluate occlusion of a cerebral artery using a pulse wave.

  In order to achieve the above object, the arterial occlusion determination device according to the present invention is characterized by measuring means for measuring pulse wave data of a human carotid artery, the carotid artery based on the pulse wave data, and a cerebral artery branching from the carotid artery Determining means for determining the presence or absence of occlusion in the left and right, and the determining means compares the left pulse wave data of the left carotid artery and the right pulse wave data of the right carotid artery measured by the measuring means, and based on the comparison result It is to determine the presence or absence of the blockage.

  Here, according to the inventors' experiment, it was found that the presence or absence of an artery occlusion can be determined by comparing the left and right pulse wave data of the same person. Therefore, according to the above configuration, the left pulse wave data and the right pulse wave data measured by the measuring means are compared, and the presence / absence of obstruction is determined based on the comparison result, so only the measured data is compared. Therefore, it is not necessary to separate the incident wave and the reflected wave as in Patent Document 1 described above, and it is possible to easily and quickly determine the presence or absence of blockage in the carotid artery and the cerebral artery branched from the carotid artery.

  The said structure WHEREIN: The said determination means is good to calculate the maximum value of a cross-correlation function from the said left pulse wave data and the said right pulse wave data, and to determine the presence or absence of the said obstruction by comparing the maximum value with a reference value. Thereby, a quantitative comparison is possible, and the determination accuracy of the presence or absence of blockage is improved.

  In such a case, the determination unit further performs frequency analysis of the left pulse wave data and the right pulse wave data, and from each of the left pulse wave data and the right pulse wave data, based on an amplitude spectrum of a first frequency band. A ratio between the calculated first value and the second value calculated from the amplitude spectrum of the second frequency band is obtained, and the ratio of the left pulse wave data and the ratio of the right pulse wave data may be compared. . When the cross-correlation function is used, it can be determined whether or not the carotid artery and the cerebral artery are occluded, but it cannot be determined whether the occluded portion is located in the left or right artery. Therefore, after determining the presence or absence of occlusion, in each of the left pulse wave data and the right pulse wave data, comparing the ratio of the analysis results divided into the first frequency band and the second frequency band, for example, The characteristics of the frequency bands derived from the occlusion of the carotid artery and the cerebral artery can be compared, and it can be accurately determined whether the occlusion exists on the left or right.

  On the other hand, the determination means performs frequency analysis of the left pulse wave data and the right pulse wave data in a predetermined time region, and the amplitude of the first frequency band in each of the left pulse wave data and the right pulse wave data Find the ratio between the first value calculated from the spectrum and the second value calculated from the amplitude spectrum of the second frequency band, and compare the ratio of the left pulse wave data and the ratio of the right pulse wave data Then, the presence or absence of the blockage may be determined. As a result, in each of the left pulse wave data and the right pulse wave data, the ratio of the analysis results divided into the first frequency band and the second frequency band is compared. The characteristics of frequency bands to be compared can be compared, and it can be accurately determined whether there is a blockage on the left or right.

  Further, in this case, the second frequency band may be a high frequency band that is equal to or higher than a predetermined frequency in the first frequency band. According to the inventors' experiments, it has been found that the frequency band of the pulse wave derived from the blockage is often a high frequency band. Therefore, for example, by making the first frequency band the entire frequency band of the received pulse wave and making the second frequency band a high frequency band of the entire frequency band, the accuracy of determining whether or not there is a blockage is further improved. Can be made.

  Further, in such a case, the first value is a square root of the square sum of the amplitude spectrum of the first frequency band, and the second value is a square sum of the amplitude spectrum of the second frequency band. The square root of

  Further, the determination means performs frequency analysis of the left pulse wave data and the right pulse wave data, obtains a feature amount in a predetermined frequency component in each of the left pulse wave data and the right pulse wave data, and It is also possible to compare the feature amount of the pulse wave data with the feature amount of the right pulse wave data to determine the presence or absence of the blockage. As described above, the frequency band of the reflected wave of the pulse wave derived from blockage is often a high-frequency band. For example, the presence / absence of blockage is determined by comparing the amplitude spectrum of the high-frequency band as a feature amount. It is also possible to determine which blockage exists on the left or right.

  The pulse wave data may be a differential waveform of the pulse wave waveform. The determination unit may extract a waveform corresponding to a predetermined number of waves from the pulse wave waveform or the differential waveform, and generate an addition average waveform by averaging the extracted waveforms. When the extracted waveforms are added and averaged, randomly generated noises cancel each other, so that the influence of noise is reduced and the accuracy of determining whether or not there is a blockage is further improved.

  As the measurement means, for example, a piezoelectric transducer is used. By using a piezoelectric transducer to measure the differential waveform of the pulse waveform that shows the time variation of the displacement of the blood vessel wall such as the carotid artery as pulse wave data, noise caused by breathing and body fluctuations during measurement is reduced. This can further improve the accuracy of determining the presence or absence of obstruction.

  In any one of the above-described configurations, the amplification unit that receives and amplifies the pulse wave data measured by the measurement unit, the A / D conversion unit that converts the amplified pulse wave data into digital data, and the converted pulse wave It is good to further have a data conversion means which has a transmission part which transmits data to the above-mentioned judgment means. In such a case, the data conversion means may include a display unit that displays the pulse wave data. Thereby, for example, it is possible to easily determine whether the pulse wave data is appropriately measured in an emergency medical field, and the determination accuracy of the presence or absence of obstruction is further improved.

  In order to achieve the above object, a program for causing the apparatus to function as an arterial occlusion determination device according to the present invention is characterized in that the left pulse wave data of the left carotid artery of the human body and the right pulse wave of the right carotid artery measured by the measuring means. The comparison is made with data, and based on the comparison result, it is made to function as a determination means for determining the presence or absence of blockage in the carotid artery and the cerebral artery branched from the carotid artery.

  According to the features of the arterial occlusion determination device and the program for functioning as the arterial occlusion determination device according to the present invention, it becomes possible to evaluate cerebral artery occlusion and the like simply and quickly using a pulse wave.

  Other objects, configurations, and effects of the present invention will become apparent from the following embodiments of the present invention.

It is a figure which shows the artery occlusion evaluation apparatus which concerns on this invention. It is a figure explaining the positional relationship with the measurement position of a cerebral artery and a carotid artery, and a pulse wave. It is a figure explaining the incident pressure wave and reflected pressure wave which comprise a pulse wave. It is a block diagram of an arterial occlusion evaluation device. It is a figure which shows an example of the differential waveform of the pulse wave obtained by the measurement means. It is a figure explaining the waveform obtained with the measuring device, and an addition average process. It is a figure which shows the time change of the differential waveform of a pulse wave, (a) is a healthy person's pulse wave, (b) is a pulse wave of an obstruction patient. It is a figure which shows the result of having analyzed the cross-correlation process of the differential waveform of the pulse wave of a healthy person and an obstruction patient, respectively. It is a figure which shows an example of the result of having performed the time frequency analysis of the differential waveform of each pulse wave of the left and right of an obstruction patient, (a) is the analysis result of the differential waveform of the left pulse wave without obstruction, (b) is obstruction. It is an analysis result of the differential waveform of the right pulse wave with. It is the figure which plotted the right-and-left difference of the ratio of the square root of the square sum of an amplitude spectrum by carrying out the time frequency analysis of the differential waveform of each right and left pulse wave of a healthy person and an obstruction patient. It is a figure which shows an example of the result of having analyzed the differential waveform of the right and left pulse wave of a healthy person. It is a figure which shows an example of the result of having analyzed the differential waveform of the left and right pulse wave of an obstruction patient. It is a figure which shows an example of the pulse wave waveform which integrated the differential waveform of the pulse wave obtained by the measurement means.

Next, the first embodiment of the present invention will be described in more detail with reference to FIGS.
As shown in FIG. 1 and FIG. 2, the arterial occlusion determination device 1 according to the present invention generally includes a measuring unit 2 that measures a pulse wave P in an artery of a human body H, and the measured pulse wave P to a determining unit 4. Data conversion means 3 for transmission, and determination means 4 for determining the presence or absence of occlusion Oc in the carotid artery 110 and the cerebral artery 120 branched from the carotid artery 110 based on pulse wave data. In the example shown in the figure, the data conversion means 3 and the determination means 4 communicate with each other by wire, but wireless communication means such as Bluetooth (registered trademark) may be used.

  By the way, ischemic cerebrovascular disease mainly caused by the occlusion Oc of the cerebral artery 120 illustrated in FIG. 2 or the occlusion Oc of the internal carotid artery 113 illustrated in FIG. 3 is promptly treated when symptoms appear. Therefore, for example, in the emergency medical field, it is required to determine whether or not there is such a blockage Oc during transportation. In the present invention, not only the cerebral artery 120 but also the carotid artery 110 branching to the cerebral artery 120 is targeted. The carotid artery 110 includes a common carotid artery 111, an external carotid artery 112 that branches from the common carotid artery 111, and an internal carotid artery 113. Hereinafter, the carotid artery 110 to be examined and the cerebral artery 120 branched from the carotid artery 110 are referred to as “cerebral artery 100 or the like”. The term “occlusion Oc” refers to a case where a part or all of the blood vessel Bv is narrowed (closed), including the case where the artery is narrowed for some reason.

  Here, the pulse wave P, as shown in FIG. 3, is a change in blood pressure and volume in the vascular system accompanying the pulsation of the heart h, and is a composite waveform of the incident wave Pi and the reflected wave Pr. The incident wave Pi is a forward wave and is caused by a pressure wave caused by blood squeezed out from the heart h. The reflected wave Pr is a receding wave, and is due to the pressure wave reflected by the incident wave Pi from a blood vessel bed (a region composed of microvessels such as capillaries and surrounding tissues). When there is a blockage Oc or stenosis in the blood vessel up to the blood vessel bed, the light is reflected at that point. In particular, the pulse wave P measured by the carotid artery 110 includes a wave reflected by a blood vessel bed or the like such as the end 130 of the cerebral artery 120. Information on the carotid artery 110 and the cerebral artery 120 branched from the carotid artery 110 is obtained. It is known to reflect. Therefore, by using the pulse wave P measured by the carotid artery 110, it is possible to determine the presence or absence of the blockage Oc of the cerebral artery 100 or the like.

  In this embodiment, as shown in FIG. 4, a piezoelectric transducer 20 that outputs a skin displacement that changes depending on the pressure of the pulse wave P is used as the measuring unit 2. In this embodiment, skin displacement is measured and used as the displacement of the blood vessel wall Vw. As shown in FIG. 5, the waveform output from the piezoelectric transducer 20 is a differential waveform (velocity waveform) of the displacement waveform of the blood vessel wall Vw due to the pulse wave P. In this embodiment, this differential waveform (velocity waveform). Is the analysis target. Hereinafter, the pulse wave data Pd indicates a velocity waveform output from the piezoelectric transducer 20. The measured pulse wave data Pd is sent to the data conversion means 3.

  The piezoelectric transducer 20 can output not only the velocity waveform but also the displacement of the blood vessel wall Vw as a displacement waveform. Since the differential waveform is the gradient of the displacement waveform, the change of the displacement waveform is reflected sharply. Therefore, as described above, it is preferable to use the differential waveform representing the speed change as it is.

  As shown in FIG. 4, the data converting means 3 receives an amplified pulse wave data Pd and amplifies it, and an A / D converter 31 converts the amplified pulse wave data Pd into digital data. And a transmission unit 32 that transmits the converted pulse wave data Pd to the determination unit 4 described later. Moreover, you may further provide the display output part 34 which displays measured pulse wave data Pd or a measurement condition. Since the pulse wave data Pd can be confirmed at an emergency medical site or the like, it is possible to prevent erroneous determination of the presence or absence of the obstruction Oc caused by a measurement error.

  As shown in FIG. 4, the determination unit 4 includes a receiving unit 40 that receives the pulse wave data Pd from the transmitting unit 32, a normalization processing unit 41 that normalizes the received pulse wave data Pd, and the pulse wave data Pd. An integration processing unit 42 that integrates the pulse wave data Pd, an addition average processing unit 43 that performs an averaging process on the pulse wave data Pd, a determination unit 44 that analyzes the pulse wave data Pd to determine whether or not there is an obstruction Oc, and an analysis result and a determination result And a storage unit 46 for storing the pulse wave data Pd, analysis results, determination results, and the like.

  As this determination means 4, for example, a personal computer (PC), a portable terminal such as a tablet or a smartphone can be used, and it may be implemented as a program (application) executed by these. Further, the determination means 4 may be carried by a medical worker at an emergency medical site or may be arranged at an emergency transport destination such as a hospital. In such a case, data is transmitted from the transmission unit 32 of the data conversion means 3 via communication means such as the Internet.

  The receiving unit 40 receives the pulse wave data Pd as shown in FIG. The normalization processing unit 41 normalizes the pulse wave data Pd received by the receiving unit 40. Normalization means multiplying the maximum amplitude value of the pulse wave data Pd by a constant value to be, for example, 1 and further multiplying all the data included in the pulse wave data Pd by the same constant value to obtain the left and right pulse waves. In this process, the maximum amplitude value of the data Pd is set to 1, and the waveform shapes can be compared.

  As shown in FIG. 6, the addition average processing unit 43 extracts waveforms Pd1 to Pd4 corresponding to a predetermined wave number from the pulse wave data Pd, and performs an addition average process on the extracted waveforms. Specifically, the averaging is performed by aligning the time at which the waveform starts, adding each waveform, and dividing by the wave number. In the example shown in the figure, waveforms Pd1 to P4 corresponding to four wave numbers are extracted from the pulse wave data Pd, and the waveforms Pd1 to Pd4 are added and averaged to obtain an added average waveform Pd '. This averaging process is performed on the left and right data. By executing the addition averaging process, the noises can be removed from the pulse wave data by canceling out random noises included in the measurement of the pulse wave data, thereby improving the accuracy of determining whether or not there is a blockage. Of course, the wave number is not limited to four and can be set as appropriate.

  In the present embodiment, the determination unit 44 includes a cross correlation analysis unit 44a and a time frequency analysis unit 44b as shown in FIG. An example of the pulse wave data analyzed and determined by the determination unit 44 is shown in FIG. (A) is obtained by superimposing the right pulse wave data on the left pulse wave data of the healthy person, and (b) is obtained by superimposing the right pulse wave data (occlusion side) on the left pulse wave data of the obstructed patient. is there. As shown in this figure, it can be seen that the pulse wave data of the right and left of the healthy person are substantially coincident, while the pulse wave data of the obstructed patient is not coincident. In this way, it is possible to determine the presence or absence of the blockage Oc of the cerebral artery 100 or the like based on the overlapping state of the left and right pulse wave data.

  Therefore, in the present embodiment, when the cross-correlation analysis unit 44a calculates the maximum value of the cross-correlation function from the left and right pulse wave data Pd and compares the maximum value with the reference value and is smaller than the reference value, the cerebral artery Etc., it is determined that there is a blocking Oc.

  The inventors calculated the maximum value of the cross-correlation function from the pulse wave data of the healthy subject and the obstructed patient in order to verify the overlap of the left and right pulse wave data Pd. The result is shown in FIG. In the example of this figure, the maximum value of healthy persons exceeds 0.85 at least. On the other hand, the maximum value of obstructed patients is about 0.75 at the maximum. Therefore, for example, by setting the reference value to about 0.75 to 0.80, it is possible to quantitatively determine the presence or absence of the blockage Oc of the cerebral artery 100 or the like.

  The time frequency analysis unit 44b performs time frequency analysis of the left pulse wave data and the right pulse wave data in a predetermined time region, calculates an amplitude spectrum at each frequency, and outputs the left pulse wave data and the right pulse wave data at each frequency. For each of the first value calculated from the amplitude spectrum of the first frequency band and the second value calculated from the amplitude spectrum of the second frequency band, the ratio of the left pulse wave data and The right pulse wave data ratio is compared, and if there is a left-right difference greater than or equal to a predetermined amount (value), it is determined that there is a blockage Oc of the cerebral artery 100 or the like with a larger value. As a time-frequency analysis, short-time Fourier transform (STFT) is performed. In the present embodiment, the first value is the square root of the square sum of the amplitude spectrum of the first frequency band, and the second value is the square root of the square sum of the amplitude spectrum of the second frequency band. It is.

  FIG. 9 shows the result of time-frequency analysis of the left and right pulse wave data Pd of an obstructed patient having an obstruction Oc in the cerebral artery 100 or the like. The solid line indicates the measured pulse wave data. (A) is a left pulse waveform without occlusion, and (b) is a right pulse waveform with occlusion. In this figure, compared with the left pulse waveform without occlusion, in the right pulse waveform with occlusion, the color is darker in the time domain where the reflected wave Pr is superimposed (after about 100 ms from the wave front), and the high frequency component It can be seen that many are included.

  If the velocity of the incident wave Pi is constant, the occlusion point is somewhere in the blood vessel Bv from the measurement point to the vascular bed such as the end 130 of the cerebral artery, so the time for the reflected wave Pr to return to the measurement point is It becomes shorter when there is a blocking Oc. That is, the time until the reflected wave Pr is superimposed on the incident wave Pi is shorter when there is the blocking Oc. Therefore, in the component of the pulse wave P due to the reflected wave Pr, the ratio of the high frequency component becomes large.

  Therefore, the inventors conducted an analysis in order to confirm the effectiveness. In the analysis, assuming that the high-frequency component is derived from the blockage Oc of the cerebral artery 100 or the like, the first frequency band is set to 1 to 100 Hz, and the square root of the square sum of the amplitude spectrum of the first frequency band is calculated. The second frequency band was set to a high frequency band (10 to 100 Hz) of 1 to 100 Hz, and the square root of the square sum of the amplitude spectrum of the second frequency band was calculated. And the numerical value (henceforth a spectral ratio) which remove | divided the square root of the 2nd frequency band by the square root of the 1st frequency band was compared with right and left.

  The spectrum ratio calculated from the pulse wave data of the healthy person and the obstructed patient is shown in FIG. As is apparent from this figure, in the healthy person, the left and right spectral ratios are almost the same, and the left / right difference is about 0.07 at the maximum. On the other hand, in the obstructed patient, there is a large difference between the obstructed side and the non-occluded side, which is at least about 0.11. Therefore, for example, by setting the reference value to about 0.08 to 0.10, it is possible to quantitatively determine the presence or absence of blockage Oc of the cerebral artery 100 or the like. Further, since the spectrum ratio on the occlusion side becomes larger, it is possible to determine which of the left and right cerebral arteries 100 has the occlusion Oc.

Next, a procedure for determining the presence or absence of blockage of the cerebral artery 100 or the like using the arterial blockage determination device 1 of the present embodiment will be described.
First, the pulse wave data Pd is measured by applying the piezoelectric transducer 20 to the left common carotid artery 111, and the pulse wave data Pd is sent to the data conversion means 3. If the pulse wave data Pd is measured by the data conversion means 3, the pulse wave data Pd is amplified by the amplifier 30, converted by the A / D converter 31, and the converted pulse wave data Pd is transmitted. The data is transmitted to the determination unit 4 by the unit 32. Thereafter, the piezoelectric transducer 20 is applied to the right common carotid artery 111, and the pulse wave data Pd is measured in the same manner, and data processing is performed.

  Here, the pulse wave measurement location is the left and right common carotid arteries 111, but is not limited thereto, and may be, for example, the external carotid artery 112 or the internal carotid artery 113. However, considering the ease of measurement and the range in which the presence or absence of occlusion Oc can be determined, it is desirable to measure the pulse wave P in the common carotid artery 111 before branching rather than the internal carotid artery 113 after branching. Note that the pulse wave P of the right common carotid artery 111 was measured and then the pulse wave P of the right common carotid artery 111 was measured.

  The transmitted pulse wave data Pd is received by the receiving unit 40, and the received pulse wave data Pd is normalized by the normalization processing unit 41, added and averaged by the addition average processing unit 43, and sent to the determination unit 44. Sent.

  The addition-averaged pulse wave data Pd is sent to the determination unit 44, where cross-correlation processing is performed in the cross-correlation analysis unit 44a, and the maximum value of the cross-correlation function is compared with the reference value, so that the presence or absence of occlusion Oc Is determined. When the cross-correlation analysis unit 44a determines that the blockage Oc is present, the pulse wave data Pd is then subjected to time-frequency analysis by the time-frequency analysis unit 44b, and the spectral ratio is compared between the left and right sides. Is determined to be on the left or right. When the cross correlation analysis unit 44a determines that there is no blockage Oc, it is not necessary to perform time frequency analysis. Thereafter, a result including the presence / absence of the blockage Oc and whether the blockage Oc is present on the left or right side is output to the display unit 45 and stored in the storage unit 46.

Finally, reference is made to the possibilities of other embodiments of the invention. In addition, the same code | symbol is attached | subjected to the member similar to the above-mentioned embodiment.
In the above embodiment, in the determination unit 44, the cross-correlation analysis is performed by the cross-correlation analysis unit 44a, and then the time-frequency analysis is performed by the time-frequency analysis unit 44b. However, the present invention is not limited to this, and only one of them may be used. However, in the case of only the cross-correlation process, it cannot be determined whether there is a blockage on the left or right, so it is preferable to provide the cross-correlation analysis unit 44a and the time-frequency analysis unit 44b as in the above embodiment.

  In the above embodiment, the time-frequency analysis unit 44b uses the square root of the square sum of the amplitude spectrum as the first and second values calculated from the amplitude spectra in the first and second frequency bands. The square root of the sum of squares of the amplitude spectrum corresponds to the effective value of the amplitude. However, the present invention is not limited to this. For example, the sum of squares of amplitude spectra or the sum of amplitude spectra of frequency bands may be used. The sum of squares of the amplitude spectrum corresponds to the energy of the pulse wave.

  Moreover, in the said embodiment, the determination part 44 was comprised from the cross correlation analysis part 44a and the time frequency analysis part 44b. However, for example, the frequency analysis unit 44c may be used instead of the time frequency analysis unit 44b. The frequency analysis unit 44c performs frequency analysis on the left pulse wave data and the right pulse wave data, calculates an amplitude spectrum at each frequency, and uses this as a feature amount. When the left and right amplitude spectra included in a specific frequency band are compared, and there is a left-right difference of a predetermined amount or more, it can be determined that there is a blockage Oc of the cerebral artery 100 or the like in the direction with the larger amplitude spectrum. For example, fast Fourier transform (FFT) is performed as a frequency analysis technique. The frequency analysis unit 44c alone may be used instead of the cross correlation analysis unit 44a and the time frequency analysis unit 44b.

  Here, the result of frequency analysis of the pulse wave data of a healthy person is shown in FIG. Similarly, FIG. 12 shows the result of frequency analysis of pulse wave data of an obstructed patient. As is clear from these figures, the pulse wave data of a healthy person has no significant difference between left and right, but the pulse wave data of an obstructed patient has a higher frequency component than 10 Hz particularly on the obstruction side. As described above, the pulse wave data on the occlusion side tends to have a high frequency component. Therefore, for example, by comparing feature amounts of frequency components higher than 10 Hz, it can be determined whether the blockage Oc is on the left or right.

  Furthermore, as shown in FIG. 8, the determination unit 44 can also determine the presence or absence of the blockage Oc based on the overlapping state of the left and right pulse wave data Pd. Moreover, it is good to make it determine whether Oc exists in right and left by combining with the time frequency analysis part 44b or the frequency analysis part 44c.

  In the above-described embodiment, the short-time Fourier transform (STFT) is used as the time-frequency analysis technique of the time-frequency analysis unit 44b. In addition, fast Fourier transform (FFT) is used as a frequency analysis method of the frequency analysis unit 44c. However, it is not limited to these, and for example, wavelet transform or the like may be used. Note that the FFT can shorten the processing time.

  In the above embodiment, since the pulse wave P is handled as the differential waveform measured by the piezoelectric transducer 20, the integration processing performed by the integration processing unit 42 indicated by a broken line in FIG. 4 is omitted. However, the integration processing unit 42 may perform integration processing on the normalized pulse wave data Pd. In this case, the pulse wave data Pd is waveform data representing the displacement of the blood vessel wall as shown in FIG. Then, it may be output to the display unit 45 separately from the differential waveform, or may be stored in the storage unit 46 so that it can be used for other purposes. Furthermore, it is also possible to facilitate the confirmation of the measured pulse wave P by performing integration processing in the waveform integration unit 33 of the data conversion unit 3 and causing the display output unit 34 to display the integration process.

  In the above embodiment, the piezoelectric transducer 20 is used as the measuring means 2. However, the measuring means 2 is not limited to this, and is not limited to the piezoelectric transducer 20 as long as it can measure the pulse wave P (displacement of the blood vessel wall). Examples of other sensors used for the measuring means 2 that measures the displacement waveform of the blood vessel wall Vw include a magnetic sensor and an optical sensor. Moreover, it is also possible to measure the displacement waveform of the carotid artery wave using an ultrasonic diagnostic apparatus equipped with an ultrasonic sensor as the measuring means 2. However, since the device is larger than the piezoelectric transducer 20 and it is difficult to carry it to an emergency medical site, the above embodiment is excellent.

  In the above embodiment, the pulse wave data Pd is a differential waveform measured by the piezoelectric transducer 20. However, for example, depending on the measuring means 2, it is also possible to output a twice differential waveform signal of the displacement waveform of the blood vessel wall Vw by the pulse wave P, and this double differential waveform signal may be used as the pulse wave data Pd. In this case, in order to make the twice differentiated waveform a displacement waveform, the integration processing may be performed twice by the waveform integration unit 33 or the integration processing unit 42. Alternatively, a twice-differential waveform obtained by further differentiating the differential waveform measured by the piezoelectric transducer 20 may be used as the pulse wave data Pd.

  In the above embodiment, the measurement unit 2 and the data conversion unit 3 are connected by wire, but the data conversion unit 3 may be omitted and the measurement unit 2 may transmit to the determination unit 4. In such a case, the determination unit 4 may be provided with an amplification unit that amplifies the pulse wave data Pd and an A / D conversion unit that performs A / D conversion. Further, the measuring means 2 and the data converting means 3 may be an integrated device.

  In the above embodiment, the left and right pulse waves P were measured using one measuring means 2. However, the left and right pulse waves P may be measured simultaneously using a pair of measuring means 2. In such a case, a pair of data conversion means 3 is provided in accordance with the measurement means 2. In one measuring means 2, the pulsation of the heart that generates the pulse wave P is different on the left and right, whereas when the pair of measuring means 2 is used, the pulsation of the heart that generates the pulse wave P is the same on the left and right. It is. Therefore, the accuracy of determining the presence or absence of the blocking Oc is further improved.

  Note that before one pulse wave P is measured and transmitted to the determination unit 4, the other pulse wave P may be measured and the left and right pulse wave data Pd may be transmitted to the determination unit 4 at the same time. For example, the data conversion unit 3 may be provided with a transmission button for transmitting the left and right pulse wave data Pd to the determination unit 4, and data transmission may be performed by operating the button.

  In the above embodiment, the pulse wave data Pd may include information indicating which pulse wave P is left or right. As a result, it becomes clear which pulse wave data Pd is obtained by measuring the left and right pulse waves P, and in particular, when determining whether the blockage Oc is on the left or right, the possibility of misdiagnosis can be reduced. . For example, the data conversion means 3 may be provided with a switch for designating which of the left and right common carotid arteries 111 the piezoelectric transducer 20 is applied to.

  In FIG. 4, the normalization processing unit 41, the integration processing unit 42, and the addition average processing unit 43 are described in this order, but the present invention is not limited to this. For example, the pulse wave data Pd may be added and averaged, normalized, integrated, and then the pulse wave data Pd may be sent to the determination unit 44 to determine the presence or absence of the blockage Oc. Further, similarly to the integration processing unit 42, each processing in the normalization processing unit 41 and the addition average processing unit 43 may be omitted.

  INDUSTRIAL APPLICABILITY The present invention can be used as an arterial occlusion determination device that determines the presence or absence of an obstruction of a cerebral artery or the like in an emergency medical field. In addition, it can be used for treatment of obstructed patients and evaluation of post-operative progress, and for people with high risk of obstruction such as cerebral arteries to monitor the obstruction status on a daily basis at home.

1: cerebral artery occlusion determination device, 2: measurement means (piezoelectric transducer), 3: data conversion means (data logger), 4: determination means (smartphone, PC), 20: sensor, 30: amplification unit, 31: A / D conversion unit, 32: transmission unit, 33: waveform integration unit, 34: display output unit, 40: reception unit, 41: normalization processing unit, 42: integration processing unit, 43: addition averaging processing unit, 44: determination unit 44a: cross-correlation analysis unit, 44b: time-frequency analysis unit, 44c: frequency analysis unit, 45: display unit, 46: storage unit, 100: cerebral artery, etc. (site to be examined), 110: carotid artery, 111: common carotid artery 112: external carotid artery, 113: internal carotid artery, 120: cerebral artery, 130: terminal of cerebral artery, P: pulse wave, Pi: incident wave, Pr: reflected wave, Pd: pulse wave data, Pd1 to Pd4: extracted Pulse wave data, Pd ': Calculated average pulse wave data, Bv: Vascular, h: Heart, Vw: vascular wall, H: human

Claims (14)

A measuring means for measuring pulse wave data of the carotid artery of the human body,
Determination means for determining the presence or absence of occlusion in the carotid artery and the cerebral artery branched from the carotid artery based on the pulse wave data,
The determination means compares the left pulse wave data of the left carotid artery measured by the measurement means with the right pulse wave data of the right carotid artery, and determines whether or not the obstruction is present based on the comparison result. The artery according to claim 1, wherein the determination means calculates a maximum value of a cross-correlation function from the left pulse wave data and the right pulse wave data and compares the maximum value with a reference value to determine the presence or absence of the blockage. Blockage determination device. The determination means further performs a frequency analysis of the left pulse wave data and the right pulse wave data, and is calculated from an amplitude spectrum of a first frequency band for each of the left pulse wave data and the right pulse wave data. 3. The ratio between the first value and the second value calculated from the amplitude spectrum of the second frequency band is obtained, and the ratio of the left pulse wave data is compared with the ratio of the right pulse wave data. Arterial occlusion determination device. The determination means performs frequency analysis of the left pulse wave data and the right pulse wave data in a predetermined time region, and from each of the left pulse wave data and the right pulse wave data, based on an amplitude spectrum of a first frequency band. The ratio between the calculated first value and the second value calculated from the amplitude spectrum of the second frequency band is obtained, and the ratio of the left pulse wave data and the ratio of the right pulse wave data are compared. The arterial occlusion determination device according to claim 1, wherein the presence or absence of the occlusion is determined. The arterial occlusion determination device according to claim 3 or 4, wherein the second frequency band is a high frequency band equal to or higher than a predetermined frequency in the first frequency band. The first value is a square root of a square sum of an amplitude spectrum of the first frequency band, and the second value is a square root of a square sum of an amplitude spectrum of the second frequency band. The arterial occlusion determination device according to any one of Items 3 to 5. The determination means performs a frequency analysis of the left pulse wave data and the right pulse wave data, obtains a feature amount in a predetermined frequency component in each of the left pulse wave data and the right pulse wave data, and the left pulse wave The arterial occlusion determination device according to claim 1, wherein the feature amount of the data and the feature amount of the right pulse wave data are compared to determine the presence or absence of the occlusion. The determination means further performs a frequency analysis of the left pulse wave data and the right pulse wave data, obtains a feature amount at a predetermined frequency component in each of the left pulse wave data and the right pulse wave data, and The arterial occlusion determination device according to claim 2, wherein the feature amount of the pulse wave data is compared with the feature amount of the right pulse wave data. The arterial occlusion determination device according to claim 1, wherein the pulse wave data is a differential waveform of a pulse wave waveform. The arterial occlusion determination device according to claim 9, wherein the determination unit extracts a waveform corresponding to a predetermined wave number from the pulse wave waveform or the differential waveform, and generates an addition average waveform by averaging the extracted waveforms. The arterial occlusion determination device according to claim 1, wherein the measuring unit is a piezoelectric transducer. An amplification unit that receives and amplifies the pulse wave data measured by the measurement unit, an A / D conversion unit that converts the amplified pulse wave data into digital data, and transmits the converted pulse wave data to the determination unit The arterial occlusion determination device according to any one of claims 1 to 11, further comprising a data conversion unit including a transmission unit. The arterial occlusion determination device according to claim 12, wherein the data conversion unit includes a display unit that displays the pulse wave data. Computer
Comparing the left pulse wave data of the left carotid artery of the human body and the right pulse wave data of the right carotid artery measured by the measuring means, and based on the comparison result, the presence or absence of blockage in the carotid artery and the cerebral artery branching from the carotid artery is determined. A program that functions as a determination means.