Biological information processing method, biological information processing device, and program

Abstract

To provide a biological information processing method and a biological information processing device capable of automatically acquiring information on liquid flowing in the body of a subject.SOLUTION: A biological information processing method includes: a step S1 for acquiring a plurality of reflection signals of an ultrasonic wave reflected by a biological tissue of a subject; a step S2 for specifying two or more ultrasonic elements facing a tube through which liquid flows of a plurality of ultrasonic elements on the basis of the plurality of reflection signals; a step for specifying a first position in an irradiation direction of the ultrasonic wave of a part of the tube facing a first ultrasonic element; a step for specifying a second position in the irradiation direction of the ultrasonic wave of a part of the tube facing a second ultrasonic element; a step S3 for specifying an angle of the tube with respect to the irradiation direction of the ultrasonic wave on the basis of the first position and the second position; a step S4 for specifying a Doppler deviation frequency generated in the ultrasonic wave reflected by the liquid flowing in the tube; and steps S5 and S7 for acquiring information related to the liquid.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a biometric information processing method and a biometric information processing device. In particular, the present disclosure relates to a biometric information processing method and a biometric information processing device using an ultrasonic sensor having a plurality of ultrasonic elements arranged in two dimensions. Furthermore, the present disclosure relates to a program for causing a computer to execute the biometric information processing method. [Background technology]

[0002] Currently, ultrasonic diagnostic devices that generate image data showing a region of interest (ROI) of a patient's biological tissue using an ultrasonic sensor equipped with a plurality of transducer elements that emit ultrasonic beams, and then display the image data on a display unit, are in widespread use (see, for example, Patent Document 1). The ultrasonic sensor can detect information about various biological tissues of the patient, and can detect, for example, the speed (blood flow velocity) and amount (blood flow rate) of blood flowing in the patient's blood vessels. In this regard, in order to diagnose the state of the patient's brain, information about the blood flow rate of the carotid artery may be obtained from the blood flow velocity of the carotid artery using the ultrasonic sensor. Here, in order to calculate the blood flow velocity of the patient using the ultrasonic sensor, it is necessary to measure the Doppler shift frequency of the ultrasonic waves reflected by red blood cells in the blood. Furthermore, the blood flow velocity is calculated from the measured Doppler shift frequency, taking into account the angle of the blood vessel with respect to the irradiation direction of the ultrasonic beam. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-86726 A Summary of the Invention [Problem to be solved by the invention]

[0004] Conventionally, medical personnel visually determine the angle of the blood vessel relative to the irradiation direction of the ultrasonic beam from the ultrasonic image data acquired by the ultrasonic sensor and the set angle of the ultrasonic beam. On the other hand, since the determination of the blood vessel angle depends on the experience and skill of the medical personnel, the accuracy of the blood vessel angle may vary depending on the medical personnel in charge. As a result, the accuracy of the blood flow velocity and blood flow rate finally determined varies depending on the medical personnel in charge. From the above viewpoint, there is room for consideration of a method for automatically acquiring information related to the fluid flowing inside the subject's body, such as the blood flow rate of the blood vessel.

[0005] An object of the present disclosure is to provide a biological information processing method and a biological information processing device capable of automatically acquiring information related to a fluid flowing inside the body of a subject. [Means for solving the problem]

[0006] A biological information processing method according to one aspect of the present disclosure is a method for automatically acquiring information related to a fluid flowing inside a body of a subject, using an ultrasonic sensor having a plurality of ultrasonic elements each configured to emit ultrasonic waves toward biological tissue of the subject, the method comprising: acquiring a plurality of ultrasonic reflection signals reflected by the biological tissue; Identifying two or more ultrasonic elements that face a pipe through which the fluid flows among the plurality of ultrasonic elements based on the plurality of reflected signals; determining a first position of a portion of the pipe facing the first ultrasonic element in a direction of irradiation of the ultrasonic waves by analyzing a reflected ultrasonic signal associated with a first ultrasonic element of the two or more ultrasonic elements; determining a second position of a portion of the pipe facing the second ultrasonic element in a direction of irradiation of the ultrasonic waves by analyzing a reflected ultrasonic signal associated with a second ultrasonic element of the two or more ultrasonic elements; determining an angle of the tube with respect to a direction of irradiation of the ultrasonic wave based on the first position and the second position; Identifying a Doppler shift frequency of an ultrasonic wave reflected by a fluid flowing in the pipe by analyzing a reflected ultrasonic signal associated with the first ultrasonic element or the second ultrasonic element; obtaining information related to the fluid based at least on the tube angle and the Doppler shift frequency; Includes.

[0007] According to the above method, a biological information processing method is provided that can automatically acquire information (e.g., blood flow velocity and blood flow rate) related to a fluid (e.g., blood) flowing inside the subject's body. Since the fluid-related information is acquired automatically in this way, it is possible to preferably prevent variation in the accuracy of the fluid-related information depending on the experience and skill of the medical professional in charge. Furthermore, since the fluid-related information is acquired automatically without manual operation by the medical professional, it is possible to reduce the workload of the medical professional.

[0008] Further, a program for causing a computer to execute the biometric information processing method may be provided.

[0009] A bioinformation processing device according to one aspect of the present disclosure is configured to automatically acquire information related to a fluid flowing within a subject's body using an ultrasonic sensor having a sheet and a plurality of ultrasonic elements arranged two-dimensionally on the sheet, each of which is configured to emit ultrasonic waves toward the subject's biological tissue. The biometric information processing device includes one or more processors and a memory that stores instructions. The instructions, when executed by the processor, cause the biometric information processing device to: acquiring a plurality of ultrasonic reflection signals reflected by the biological tissue; Identifying two or more ultrasonic elements facing a pipe through which the fluid flows among the plurality of ultrasonic elements based on the plurality of reflected signals; by analyzing a reflected signal of ultrasonic waves associated with a first ultrasonic element of the two or more ultrasonic elements, a first position of a portion of the pipe facing the first ultrasonic element in an irradiation direction of the ultrasonic waves is identified; by analyzing a reflected signal of the ultrasonic wave associated with a second ultrasonic element of the two or more ultrasonic elements, a second position of the portion of the pipe facing the second ultrasonic element in the direction of irradiation of the ultrasonic wave is identified; determining an angle of the tube with respect to a direction of irradiation of the ultrasonic wave based on the first position and the second position; By analyzing the reflected signal of the ultrasonic wave associated with the first ultrasonic element or the second ultrasonic element, a Doppler shift frequency occurring in the ultrasonic wave reflected by the fluid flowing in the pipe is identified; Information related to the fluid is obtained based at least on the tube angle and the Doppler shift frequency.

[0010] According to the above configuration, a bioinformation processing device is provided that can automatically acquire information (e.g., blood flow velocity and blood flow rate) related to a fluid (e.g., blood) flowing inside a subject's body. Since the information related to the fluid is acquired automatically in this way, it is possible to preferably prevent variation in the accuracy of the information related to the fluid depending on the experience and skill of the medical staff in charge. Furthermore, since the information related to the fluid is acquired automatically without manual operation by the medical staff, it is possible to reduce the workload of the medical staff. Effect of the Invention

[0011] According to the present disclosure, it is possible to provide a biological information processing method and a biological information processing device capable of automatically acquiring information related to a fluid flowing inside the body of a subject. [Brief description of the drawings]

[0012] [Figure 1] 1 is a diagram illustrating an example of a hardware configuration of a biometric information processing apparatus according to an embodiment of the present invention (hereinafter, referred to as the present embodiment). [Diagram 2]FIG. 1 is a plan view illustrating an example of an ultrasonic sensor. [Diagram 3] FIG. 1 is a diagram showing an ultrasonic sensor attached to the neck of a subject. [Figure 4] 1 is a flowchart illustrating a biological information processing method according to the present embodiment. [Diagram 5] 1 is a diagram showing a state in which each ultrasonic element provided in an ultrasonic sensor faces the carotid artery of a subject. [Figure 6] 11 is a flowchart for explaining a process for identifying an angle θ of a carotid artery with respect to an ultrasound irradiation direction. [Figure 7] FIG. 2 is a diagram for explaining the position of the midpoint between the anterior wall and the posterior wall of the carotid artery in the Z-axis direction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, this embodiment will be described with reference to the drawings. First, the hardware configuration of a biometric information processing device 2 (hereinafter simply referred to as the processing device 2) according to this embodiment will be described with reference to FIG. 1. FIG. 1 is a diagram showing an example of the hardware configuration of the processing device 2. As shown in FIG. 1, the processing device 2 includes a control unit 20, a storage device 21, a communication unit 25, a display unit 22, an audio output unit 28, an input operation unit 26, and a sensor interface 23. These components are connected to each other via a bus 27 so as to be able to communicate with each other. The processing device 2 is electrically connected to an ultrasonic sensor 3.

[0014] The processing device 2 may be a medical device (e.g., a vital sign monitor) for displaying vital signs of the subject P (see FIG. 3), or may be a personal computer, a workstation, a smartphone, a tablet, or a wearable device (e.g., AR glasses, etc.) attached to the body (e.g., arm, head, etc.) of a medical professional.

[0015] The control unit 20 includes a memory and a processor. The memory is configured to store computer-readable instructions (programs). For example, the memory is configured from a ROM (Read Only Memory) in which various programs and the like are stored, and a RAM (Random Access Memory) having multiple work areas in which various programs and the like executed by the processor are stored. The processor is configured from at least one of a CPU (Central Processing Unit), an MPU (Micro Processing Unit), and a GPU (Graphics Processing Unit). The CPU may be configured from multiple CPU cores. The GPU may be configured from multiple GPU cores. The processor may be configured to load a program designated from various programs incorporated in the storage device 21 or the ROM onto the RAM and execute various processes in cooperation with the RAM. In particular, the processor loads a biometric information processing program that executes the series of processes shown in FIG. 4 onto the RAM, and executes the program in cooperation with the RAM, whereby the control unit 20 executes the series of processes shown in FIG. 4. Details of the biometric information processing program will be described later.

[0016] The storage device 21 is, for example, a storage device (storage) such as a hard disk drive (HDD), a solid state drive (SSD), or a flash memory, and is configured to store programs and various data. A biological information processing program may be incorporated in the storage device 21. The storage device 21 may also store biological information data (for example, waveform data indicating time changes in blood flow volume and / or blood flow velocity) generated based on the biological signal output from the ultrasonic sensor 3.

[0017] The communication unit 25 is configured to connect the processing device 2 to an in-hospital network. Specifically, the communication unit 25 may include various wired connection terminals for communicating with a central monitor or a server arranged in the in-hospital network. The communication unit 25 may also include a wireless communication module for wirelessly communicating with the central monitor or the server. The communication unit 25 may include, for example, a wireless communication module compatible with a medical telemetry system. The communication unit 25 may also include a wireless communication module compatible with a wireless communication standard such as Wi-Fi (registered trademark) or Bluetooth (registered trademark) and / or a wireless communication module compatible with a mobile communication system using a SIM. The in-hospital network may be configured, for example, with a LAN (Local Area Network) or a WAN (Wide Area Network). The processing device 2 may be connected to the Internet via the in-hospital network.

[0018] The display unit 22 is configured to display information related to the blood flowing through the carotid artery of the subject P acquired in real time, and is configured, for example, by a liquid crystal panel or an organic EL panel. The audio output unit 28 is configured to be configured to audibly output an audio alert in response to information related to the blood flowing through the carotid artery of the subject P. The input operation unit 26 is, for example, a touch panel, a mouse, and / or a keyboard, etc., superimposed on the display unit 22. The input operation unit 26 is configured to receive an input operation by a medical professional and to generate an operation signal corresponding to the input operation by the medical professional. After the operation signal generated by the input operation unit 26 is transmitted to the control unit 20 via the bus 27, the control unit 20 executes a predetermined operation in response to the operation signal.

[0019] The ultrasonic sensor 3 is configured to detect information related to the biological tissue of the subject (information related to blood flowing through the carotid artery in this example) by emitting ultrasonic waves toward the biological tissue of the subject. As shown in FIG. 2, the ultrasonic sensor 3 includes a sheet 32, a plurality of ultrasonic elements 30, a sheet fixing portion 35, and a connection cable 34. The ultrasonic sensor 3 may be a disposable sensor. The sheet 32 ​​is attached to a predetermined part of the subject P (the neck in this example) (see FIG. 3). The sheet 32 ​​is made of a flexible material such as silicone.

[0020] The ultrasonic elements 30 are arranged two-dimensionally on one surface of the sheet 32. In this example, the ultrasonic elements 30 are arranged in a matrix of 8 rows by 8 columns. The distance between the ultrasonic elements 30 adjacent to each other in the row direction and the column direction may be approximately constant. Each ultrasonic element 30 is configured to transmit ultrasonic waves toward the biological tissue of the subject P and to receive ultrasonic waves reflected by the biological tissue. In particular, each ultrasonic element 30 is configured to transmit ultrasonic waves by vibrating in response to an electrical drive signal (high-frequency signal) transmitted from a drive circuit 331 described later, and to convert ultrasonic waves reflected by the biological tissue into an electrical signal. After being output from each ultrasonic element 30, the reflected signal of the ultrasonic waves reflected by the biological tissue is input to the sensor interface 23 via the sheet fixing part 35 and the connection cable 34. In this embodiment, each ultrasonic element 30 may output an ultrasonic pulse of a predetermined frequency (for example, 8 kHz).

[0021] The sensor interface 23 is an interface for communicatively connecting the ultrasonic sensor 3 to the processing device 2. The sensor interface 23 may include an input terminal to which a biological signal output from the ultrasonic sensor 3 is input. The input terminal may be physically connected to a connector of the ultrasonic sensor 3. The sensor interface 23 may also include an ultrasonic processing circuit 33. The ultrasonic processing circuit 33 has a drive circuit 331 and an analog processing circuit 332. The drive circuit 331 includes an oscillation circuit and is configured to generate a drive signal for driving the ultrasonic elements 30 of the ultrasonic sensor 3 and then transmit the drive signal to each ultrasonic element 30. The analog processing circuit 332 is configured to perform signal processing on the reflected signal of the ultrasonic wave output from each ultrasonic element 30. The analog processing circuit 332 includes, for example, at least a filter processing circuit that removes noise components from the reflected signal output from each ultrasonic element 30, a signal amplification circuit that amplifies the reflected signal, and an AD conversion circuit that converts the reflected signal from an analog signal to a digital signal. In this way, the analog ultrasonic reflected signal output from the ultrasonic sensor 3 is converted into a digital ultrasonic reflected signal by the sensor interface 23, and the digital reflected signal is then transmitted to the control unit 20.

[0022] Next, the biological information processing method according to this embodiment (particularly, a series of processes for acquiring information related to blood flowing through the carotid artery of the subject P) will be described below with reference mainly to FIG. 4. FIG. 4 is a flowchart for explaining the biological information processing method according to this embodiment. In the following description, as shown in FIG. 5, the X-axis direction, the Y-axis direction, and the Z-axis direction set relative to the ultrasonic sensor 3 will be referred to. One of the X-axis direction, the Y-axis direction, and the Z-axis direction is assumed to be orthogonal to the remaining two directions. The multiple ultrasonic elements 30 are assumed to be two-dimensionally arranged in the XY plane. As shown in FIG. 3, the sheet 32 ​​of the ultrasonic sensor 3 is attached to the neck of the subject P, and some of the multiple ultrasonic elements 30 are assumed to face the carotid artery 100 (an example of a blood vessel) of the subject P in the Z-axis direction perpendicular to the XY plane. The irradiation direction of the ultrasonic beam emitted from each ultrasonic element 30 is assumed to be parallel to the Z-axis direction.

[0023] 4, in step S1, the control unit 20 of the processing device 2 acquires reflected signals (digital signals) of a plurality of ultrasonic waves 40 reflected by biological tissues of the subject P from the ultrasonic sensor 3 via the ultrasonic processing circuit 33 (step S1). In particular, the control unit 20 acquires reflected signals of a plurality of ultrasonic waves 40 output from a plurality of ultrasonic elements 30.

[0024] In step S2, the control unit 20 identifies the ultrasonic elements 30 that face the carotid artery 100 of the subject P in the Z-axis direction based on the reflected signals of the multiple ultrasonic waves. As shown in Fig. 5, in this example, it is assumed that ultrasonic elements 30a to 30h out of the multiple ultrasonic elements 30 face the carotid artery 100 in the Z-axis direction.

[0025] In this regard, the control unit 20 specifies the ultrasonic elements 30a to 30h facing the carotid artery 100 in the Z-axis direction based on the components of the reflected signals of the multiple ultrasonic waves 40. In general, ultrasonic waves are reflected at the boundary between the carotid artery 100 and the biological tissue adjacent to the carotid artery 100 because they are reflected at the boundary between media with different acoustic characteristic impedances. In particular, since the difference in acoustic impedance between the carotid artery 100 and the biological tissue adjacent to the carotid artery 100 is large, the ultrasonic waves 40 are strongly reflected at the front wall 120 and the rear wall 130 of the carotid artery 100, respectively. In addition, the pattern of the reflected signal components of the ultrasonic waves 40 reflected by the front wall 120 and the rear wall 130 of the carotid artery 100 is known in advance. Here, the control unit 20 can determine the ultrasonic elements 30 associated with the reflected signals having predetermined reflected signal components (for example, the reflected signal components C1, C2, etc. shown in FIG. 7) as the ultrasonic elements facing the carotid artery 100 in the Z-axis direction.

[0026] Next, in step S3, the control unit 20 specifies the angle θ of the carotid artery 100 with respect to the irradiation direction (Z-axis direction) of the ultrasound 40 (ultrasonic beam). Specific processing of step S3 will be described in detail below with reference to FIG. 6 and FIG. 7. FIG. 6 is a flowchart for explaining processing for specifying the angle θ of the carotid artery 100 with respect to the irradiation direction (Z-axis direction) of the ultrasound 40. FIG. 7 is a diagram for explaining positions Z3 and Z6 of the midpoint between the front wall 120 and the rear wall 130 of the carotid artery 100 in the Z-axis direction. In the following description, it is assumed that the angle θ of the carotid artery 100 with respect to the Z-axis direction is specified based on the reflected signals of the ultrasound 40 transmitted from two ultrasonic elements 30b and 30d among the ultrasonic elements 30a to 30h facing the carotid artery 100. In addition, it is assumed that the thickness of the wall of the carotid artery 100 is sufficiently small.

[0027] As shown in FIG. 6, in step S10, the control unit 20 analyzes the reflected signal of the ultrasonic wave 40 transmitted from the ultrasonic element 30b (an example of a first ultrasonic element) to identify the position Z1 of the front wall 120 and the position Z2 of the rear wall 130 in the Z-axis direction of the part of the carotid artery 100 facing the ultrasonic element 30b. Specifically, the control unit 20 analyzes the reflected signal of the ultrasonic wave 40 transmitted from the ultrasonic element 30b to identify the reflected signal component of the ultrasonic wave 40 reflected by the front wall 120. Next, the control unit 20 identifies the reception time of the reflected signal component of the ultrasonic wave 40 reflected by the front wall 120. After that, the control unit 20 identifies the distance L1 between the ultrasonic element 30b and the front wall 120 in the Z-axis direction based on the transmission time t0 of the ultrasonic wave 40 and the reception time t1 of the reflected signal component of the ultrasonic wave 40 reflected by the front wall 120. Here, the distance L1=c(t1-t0) / 2. c is the sound speed of the ultrasonic wave 40 traveling in the biological tissue. In this manner, the control unit 20 can identify the position Z1 of the front wall 120 in the Z-axis direction.

[0028] Similarly, the control unit 20 analyzes the reflected signal of the ultrasonic wave 40 transmitted from the ultrasonic element 30b to identify the reflected signal component of the ultrasonic wave 40 reflected by the rear wall 130. Next, the control unit 20 identifies the reception time of the reflected signal component of the ultrasonic wave 40 reflected by the rear wall 130. After that, the control unit 20 identifies the distance L2 (L2=c(t2-t0) / 2) between the ultrasonic element 30b and the rear wall 130 in the Z-axis direction based on the transmission time t0 of the ultrasonic wave 40 and the reception time t2 of the reflected signal component of the ultrasonic wave 40 reflected by the rear wall 130. In this way, the control unit 20 can identify the position Z2 of the rear wall 130 in the Z-axis direction.

[0029] Next, in step S11, the control unit 20 identifies a position Z3 (Z3=(Z1+Z2) / 2) that is a midpoint between the position Z1 of the front wall 120 and the position Z2 of the rear wall 130 in the Z-axis direction.

[0030] In step S12, the control unit 20 analyzes the reflected signal of the ultrasonic wave 40 transmitted from the ultrasonic element 30d (an example of a second ultrasonic element) to identify the position Z4 of the front wall 120 and the position Z5 of the rear wall 130 in the Z-axis direction of the part of the carotid artery 100 facing the ultrasonic element 30d. Specifically, the control unit 20 analyzes the reflected signal of the ultrasonic wave 40 transmitted from the ultrasonic element 30d to identify the reflected signal component C1 (see FIG. 7) of the ultrasonic wave 40 reflected by the front wall 120. Next, the control unit 20 identifies the reception time of the reflected signal component C1 of the ultrasonic wave 40 reflected by the front wall 120. After that, the control unit 20 identifies the distance between the ultrasonic element 30d and the front wall 120 in the Z-axis direction based on the transmission time of the ultrasonic wave 40 and the reception time of the reflected signal component C1 of the ultrasonic wave 40 reflected by the front wall 120. In this way, the control unit 20 can identify the position Z4 of the front wall 120 in the Z-axis direction.

[0031] Similarly, the control unit 20 analyzes the reflected signal of the ultrasonic wave 40 transmitted from the ultrasonic element 30d to identify the reflected signal component C2 (see FIG. 7) of the ultrasonic wave 40 reflected by the rear wall 130. Next, the control unit 20 identifies the reception time of the reflected signal component C2 of the ultrasonic wave 40 reflected by the rear wall 130. After that, the control unit 20 identifies the distance between the ultrasonic element 30d and the rear wall 130 in the Z-axis direction based on the transmission time of the ultrasonic wave 40 and the reception time of the reflected signal component C2 of the ultrasonic wave 40 reflected by the rear wall 130. In this way, the control unit 20 can identify the position Z5 of the rear wall 130 in the Z-axis direction.

[0032] Next, in step S13, the control unit 20 identifies a position Z6 (Z6=(Z4+Z5) / 2) that is a midpoint between the position Z4 of the front wall 120 and the position Z5 of the rear wall 130 in the Z-axis direction.

[0033] In step S14, the control unit 20 determines the angle θ of the carotid artery 100 with respect to the irradiation direction of the ultrasound 40 based on the midpoint position Z3 and the midpoint position Z6. Specifically, as shown in Fig. 7, the control unit 20 determines the angle θ1 of the carotid artery 100 with respect to the X-axis direction based on the distance ΔZ between the position Z6 and the position Z3 in the Z-axis direction and the distance ΔX between the ultrasonic element 30b and the ultrasonic element 30d in the X-axis direction. More specifically, the angle θ1 is calculated by θ1=tan -1 The angle θ is calculated by (ΔZ / ΔX). Since the angle θ=(90°-θ1), the control unit 20 can specify the angle θ of the carotid artery 100 with respect to the Z-axis direction from the calculated angle θ1.

[0034] The distance ΔX may be the distance between the center position of the ultrasonic element 30b and the center position of the ultrasonic element 30d in the X-axis direction. In this example, the angle θ of the carotid artery 100 is determined based on the reflected signal of the ultrasonic wave 40 transmitted from the ultrasonic elements 30b and 30d, but this embodiment is not limited to this. For example, the angle θ of the carotid artery 100 may be determined based on the reflected signal of the ultrasonic wave 40 transmitted from the ultrasonic elements 30b and 30c or the ultrasonic elements 30c and 30d, or the angle θ of the carotid artery 100 may be determined based on the reflected signal of the ultrasonic wave 40 transmitted from any two ultrasonic elements among the ultrasonic elements 30a to 30h facing the carotid artery 100.

[0035] In this example, the angle θ of the carotid artery 100 is determined based on the distance between the positions Z3 and Z6 of the two midpoints, but this embodiment is not limited to this. For example, the angle θ of the carotid artery 100 may be determined based on the distance between the positions Z1 and Z4 of the anterior wall 120 in the Z-axis direction, or the angle θ of the carotid artery 100 may be determined based on the distance between the positions Z2 and Z5 of the posterior wall 130.

[0036] Returning to FIG. 4, in step S4, the control unit 20 calculates the Doppler shift frequency f d In this regard, the control unit 20 analyzes the reflected signal of the ultrasonic wave 40 transmitted from one or more of the ultrasonic elements 30a to 30h facing the carotid artery 100 to determine the Doppler shift frequency f generated in the ultrasonic wave reflected by blood (more specifically, red blood cells). d may be specified.

[0037] When the speed of blood flowing through the carotid artery 100 (blood flow velocity) is v, red blood cells contained in the blood also move through the carotid artery 100 at a speed v. When the angle of the carotid artery 100 with respect to the Z-axis direction is θ, the red blood cells are observed to move in the Z-axis direction at a speed of vcosθ. A portion of the ultrasonic waves 40 transmitted from the ultrasonic element 30 and passing through the carotid artery 100 is reflected by red blood cells moving at vcosθ in the Z-axis direction, and then received by the ultrasonic element 30b. In this way, the frequency of the ultrasonic waves 40 reflected by red blood cells moving at vcosθ in the Z-axis direction changes due to the Doppler effect.

[0038] Here, the frequency of the ultrasonic wave 40 transmitted from the ultrasonic element 30 is f0, and the Doppler shift frequency is f d When the velocity of blood flowing through the carotid artery 100 is v, the angle of the carotid artery 100 with respect to the Z-axis direction is θ, and the sound speed of the ultrasound traveling through the biological tissue is c, the Doppler shift frequency f d is derived from the following equation (1).

[0039] f d = 2vf0 × cosθ / c (1)

[0040] From the above equation (1), the Doppler shift frequency f d It is understood that the Doppler shift frequency f varies in proportion to the blood flow velocity v flowing through the carotid artery 100. In other words, d By measuring this, it is possible to measure the blood flow velocity v in the carotid artery 100.

[0041] The control unit 20 analyzes the reflected signal of the ultrasonic wave 40 associated with at least one of the ultrasonic elements 30a to 30h, for example, by a pulse Doppler method or a color Doppler method, thereby determining a Doppler shift frequency f d For example, the Doppler shift frequency f dWhen is specified, the control unit 20 acquires data indicating a change in the sum of the luminance values ​​of the reflected signal components C3 (see FIG. 7) of the ultrasonic waves reflected by the red blood cells in the carotid artery 100 for each ultrasonic pulse, and then performs a fast Fourier transform (FFT) process on the acquired data to obtain a Doppler shift frequency f d On the other hand, the color Doppler method allows the Doppler shift frequency f d is specified, the control unit 20 uses the autocorrelation method to determine the Doppler shift frequency f d In addition, when the frequency of the ultrasonic waves is 8 kHz (in other words, when 8000 ultrasonic pulses are output per second), the control unit 20 estimates the Doppler shift frequency f every 140 ultrasonic pulses. d In this case, the Doppler shift frequency f d The update rate is 57Hz.

[0042] Furthermore, since the pulse Doppler method requires a large computation load due to FFT, computation processing using the color Doppler method is advantageous in that the computation load on the control unit 20 is smaller than that using the pulse Doppler method.

[0043] Next, in step S5, the control unit 20 identifies the velocity v of the blood flowing through the carotid artery 100 (blood flow velocity). In this regard, the above formula (1) is modified as follows. v=(cf d ) / (2f0cosθ) (2)

[0044] The control unit 20 calculates the Doppler shift frequency f based on the above formula (2). d It is then possible to calculate the blood flow velocity v from the frequency f0, the angle θ of the carotid artery 100, and the sound speed c.

[0045] Next, in step S6, the control unit 20 specifies the cross-sectional area S of the carotid artery 100. Here, the cross-sectional area S of the carotid artery 100 is a cross-sectional area perpendicular to the axial direction of the carotid artery 100, and refers to the cross-sectional area of ​​the hollow part of the carotid artery 100 through which blood flows. Here, when the inner diameter of the carotid artery 100 is R, the cross-sectional area S of the carotid artery 100 is expressed as S=πR 2 7, when the distance between position Z1 and position Z2 is |Z1-Z2|, the inner diameter R is calculated by R=|Z1-Z2|sinθ. Similarly, when the distance between position Z3 and position Z5 is |Z4-Z5|, the inner diameter R is calculated by R=|Z4-Z5|sinθ. As mentioned above, the thickness of the wall of the carotid artery 100 is assumed to be sufficiently small.

[0046] A case where the cross-sectional area S of the carotid artery 100 is calculated based on the reflected signal of the ultrasonic wave associated with the ultrasonic element 30b will be briefly described below. In this case, first, the control unit 20 identifies the position Z1 of the anterior wall 120 and the position Z2 of the posterior wall 130 in the Z-axis direction by analyzing the reflected signal of the ultrasonic wave associated with the ultrasonic element 30b. Next, the control unit 20 identifies the distance |Z1-Z2| between the position Z1 of the anterior wall 120 and the position Z2 of the posterior wall 130. After that, the control unit 20 identifies the inner diameter R of the carotid artery 100 from the angle θ of the carotid artery 100 and the distance |Z1-Z2| based on the relational expression R=|Z1-Z2|sinθ. Finally, the control unit 20 calculates the inner diameter R of the carotid artery 100 from S=πR 2 / 4, the cross-sectional area S of the carotid artery 100 is determined from the inner diameter R of the carotid artery 100. The cross-sectional area S of the carotid artery 100 may be calculated based on a reflected signal of an ultrasonic wave associated with at least one of the ultrasonic elements 30a to 30h facing the carotid artery 100.

[0047] Next, in step S7, the control unit 20 determines the flow rate (blood flow rate) Q of blood flowing through the carotid artery 100. Here, the blood flow rate Q is expressed as Q=Sv (v is the blood flow velocity, and S is the cross-sectional area of ​​the carotid artery). In this way, the control unit 20 can determine the blood flow rate Q of the carotid artery 100 based on the calculated blood flow velocity v and the cross-sectional area S of the carotid artery 100.

[0048] In step S8, the control unit 20 outputs information related to the blood flowing through the carotid artery 100. For example, the control unit 20 may display waveform data indicating a time change in the blood flow rate Q of the carotid artery 100 and / or waveform data indicating a time change in the blood flow velocity v of the carotid artery 100 on the display screen of the display unit 22. In this case, the medical staff can accurately grasp the symptoms of the subject P by looking at the waveform data displayed on the display unit 22. In particular, the medical staff can accurately grasp the state of the brain of the subject P (in particular, the state of the supply of blood flowing to the brain) by observing the time change in the blood flow rate Q or the blood flow velocity v of the carotid artery 100.

[0049] Furthermore, the control unit 20 may determine whether the blood flow rate Q of the carotid artery 100 is equal to or less than a predetermined threshold Qth, and then audibly output an alert from the audio output unit 28 in response to the determination that the blood flow rate Q of the carotid artery 100 is equal to or less than the predetermined threshold Qth. Similarly, the control unit 20 may determine whether the blood flow velocity v of the carotid artery 100 is equal to or less than a predetermined threshold vth, and then audibly output an alert from the audio output unit 28 in response to the determination that the blood flow velocity v of the carotid artery 100 is equal to or less than the predetermined threshold vth.

[0050] In this case, the medical staff can instantly grasp the change in the brain state of the subject P (particularly, the state of the blood supply flowing to the brain) by hearing the alert output from the audio output unit 28 of the processing device 2. Furthermore, the control unit 20 may display a warning display on the display screen of the display unit 22 in response to the determination that the blood flow rate Q or the blood flow velocity v of the carotid artery 100 is equal to or lower than a predetermined threshold. In this case, similarly, the medical staff can instantly grasp the change in the brain state of the subject P by looking at the warning display displayed on the display unit 22. Furthermore, the control unit 20 may store waveform data showing the time change of the blood flow rate Q or the blood flow velocity v in the storage device 21, or may transmit the same to a central monitor or server provided on the hospital network via the communication unit 25.

[0051] In the above description, the control unit 20 presents an audible or visual warning to the medical staff in response to the determination that the blood flow rate Q or blood flow velocity v of the carotid artery 100 is equal to or less than a predetermined threshold, but the present embodiment is not limited to this. For example, the control unit 20 may present an audible or visual warning to the medical staff in response to the determination that the change in the blood flow rate Q or blood flow velocity v is equal to or less than a predetermined threshold. Here, the "change in the blood flow rate Q or blood flow velocity v" corresponds to the difference between the current blood flow rate Q or blood flow velocity v and the blood flow rate Q or blood flow velocity v a predetermined time ago.

[0052] In addition, in this embodiment, information related to the blood flowing through the carotid artery 100 is acquired based on the reflected signal of the ultrasonic waves related to the ultrasonic elements 30a to 30h facing the carotid artery 100. Therefore, after the ultrasonic elements 30a to 30h facing the carotid artery 100 are specified in step S2, only the ultrasonic elements 30a to 30h may be driven. That is, the drive circuit 331 may supply a drive signal only to the ultrasonic elements 30a to 30h. In this case, since only the ultrasonic elements 30a to 30h are driven, it is possible to reduce the amount of ultrasonic waves irradiated toward the biological tissue of the subject P. In this way, it is possible to suppress the influence of the biological tissue of the subject P caused by the irradiation of ultrasonic waves as much as possible, and to reduce the power consumption of the ultrasonic sensor 3.

[0053] As described above, according to the present embodiment, it is possible to provide a processing device 2 capable of automatically acquiring blood flow information related to blood flowing through the carotid artery 100 (for example, waveform data showing time changes in blood flow velocity v and blood flow rate Q) without manual operation by a medical professional. In this way, since the blood flow information is acquired automatically, it is possible to preferably prevent the occurrence of variations in the accuracy of the blood flow information depending on the experience and skills of the medical professional in charge. Furthermore, since the blood flow information is automatically acquired without manual operation by the medical professional, it is possible to reduce the workload of the medical professional. In particular, compared to the conventional ultrasonic diagnostic method, since the angle θ of the carotid artery 100 with respect to the irradiation direction of the ultrasonic beam and the cross-sectional area S perpendicular to the axial direction of the carotid artery 100 are automatically determined by the processing device 2, it is possible to improve the accuracy of the blood flow information and reduce the workload of the medical professional.

[0054] In addition, in order to realize the processing device 2 according to the present embodiment by software, the biometric information processing program may be pre-installed in the storage device 21 or ROM. Alternatively, the biometric information processing program may be stored in a computer-readable storage medium such as a magnetic disk (e.g., HDD, floppy disk), an optical disk (e.g., CD-ROM, DVD-ROM, Blu-ray (registered trademark) disk), a magneto-optical disk (e.g., MO), or a flash memory (e.g., SD card, USB memory, SSD). In this case, the biometric information processing program stored in the storage medium may be installed in the storage device 21. Furthermore, the program installed in the storage device 21 may be loaded onto the RAM, and then the processor may execute the program loaded onto the RAM. In this way, the biometric information processing method according to the present embodiment is executed by the processing device 2. The biometric information processing program may be downloaded from a computer on a communication network via the communication unit 25. In this case, the downloaded program may be installed in the storage device 21.

[0055] Although the embodiment of the present invention has been described above, the technical scope of the present invention should not be interpreted as being limited by the description of the embodiment. The embodiment is an example, and it is understood by those skilled in the art that various modifications of the embodiment are possible within the scope of the invention described in the claims. The technical scope of the present invention should be determined based on the scope of the invention described in the claims and its equivalents.

[0056] For example, in the description of the present embodiment, information related to blood flowing through the carotid artery is automatically acquired by the processing device 2, but the blood vessel is not limited to the carotid artery. For example, information related to blood flowing through blood vessels other than the carotid artery may be automatically acquired by the processing device 2.

[0057] Furthermore, in this embodiment, the flow rate and velocity of blood are automatically acquired by the processing device 2, but the processing device 2 may automatically acquire information related to fluids flowing inside the body of the subject other than blood. For example, the processing device 2 may automatically acquire the flow rate and velocity of urine flowing through the ureter, which is another example of the tract of the subject. In this case, the sheet 32 ​​of the ultrasonic sensor 3 is attached to the subject so as to face the ureter. Furthermore, the processing device 2 identifies the ultrasonic element facing the ureter in the Z-axis direction, and then analyzes the reflected signals of ultrasonic waves transmitted from two or more ultrasonic elements facing the ureter to determine the angle θ of the ureter with respect to the irradiation direction of the ultrasonic waves. Thereafter, the processing device 2 determines the speed and flow rate of urine flowing through the ureter by identifying the Doppler shift frequency generated in the ultrasonic waves reflected by the urine. Thereafter, the processing device 2 may display information related to the flow rate and velocity of urine (such as waveform data showing the time change of the urine flow rate) on the display unit 22. [Explanation of symbols]

[0058] 2: Biometric information processing device (processing device) 3: Ultrasonic sensor 20: Control unit 21: Storage device 22: Display section 23: Sensor interface 25: Communications Department 26: Input operation section 28: Audio output section 30, 30a to 30h: Ultrasonic element 32: Sheet 33: Ultrasonic processing circuit 40: Ultrasound 100: Carotid artery 120: Front wall 130: Rear wall 331: Drive circuit 332: Analog processing circuit

Claims

1. 1. A biological information processing method for automatically acquiring information related to a fluid flowing inside a subject's body using an ultrasonic sensor having a plurality of ultrasonic elements each configured to emit ultrasonic waves toward biological tissue of the subject, comprising: acquiring a plurality of ultrasonic reflection signals reflected by the biological tissue; Identifying two or more ultrasonic elements that face a pipe through which the fluid flows among the plurality of ultrasonic elements based on the plurality of reflected signals; determining a first position of a portion of the pipe facing the first ultrasonic element in a direction of irradiation of the ultrasonic waves by analyzing a reflected ultrasonic signal associated with a first ultrasonic element of the two or more ultrasonic elements; determining a second position of a portion of the tube facing the second ultrasonic element in a direction of irradiation of the ultrasonic waves by analyzing a reflected ultrasonic signal associated with a second ultrasonic element of the two or more ultrasonic elements; determining an angle of the tube with respect to a direction of irradiation of the ultrasonic wave based on the first position and the second position; Identifying a Doppler shift frequency of an ultrasonic wave reflected by a fluid flowing in the pipe by analyzing a reflected ultrasonic signal associated with the first ultrasonic element or the second ultrasonic element; obtaining information related to the fluid based at least on the tube angle and the Doppler shift frequency; A biometric information processing method executed by a computer, comprising:

2. The information about the fluid includes a velocity of the fluid. The method for processing biological information according to claim 1 .

3. The information about the fluid includes a flow rate of the fluid; The biological information processing method further includes a step of determining a cross-sectional area of ​​the tube, A flow rate of the fluid is determined based on a cross-sectional area of ​​the pipe and a velocity of the fluid. The method for processing biological information according to claim 2 .

4. The step of determining a cross-sectional area of ​​the tube comprises: determining a location of a front wall and a rear wall of the portion of the tube opposite the first ultrasonic element by analyzing a reflected ultrasonic signal associated with the first ultrasonic element; determining a distance between the front wall position and the rear wall position; determining a cross-sectional area of ​​the tube based on an angle of the tube with respect to the illumination direction and a distance between the front wall position and the rear wall position; The biometric information processing method according to claim 3 .

5. outputting information related to the flow rate of the fluid. The method for processing biological information according to claim 3 or 4.

6. The step of outputting information related to the flow rate of the fluid includes a step of visually presenting waveform data showing a time change of the flow rate of the fluid. The method for processing biological information according to claim 5 .

7. and outputting information related to the fluid flow rate includes audibly outputting an alert in response to determining that the fluid flow rate is equal to or less than a predetermined threshold. The method for processing biological information according to claim 5 .

8. The step of identifying the first position in the irradiation direction includes: determining a position of a first front wall and a first rear wall in the irradiation direction of a portion of the tube facing the first ultrasonic element by analyzing a reflected signal of an ultrasonic wave associated with the first ultrasonic element; determining a position of a first midpoint between the first front wall and the first rear wall in the illumination direction; Including, The step of identifying the second position in the irradiation direction includes: determining a position of a second front wall and a second rear wall in the irradiation direction of the portion of the tube facing the second ultrasonic element by analyzing a reflected signal of the ultrasonic wave associated with the second ultrasonic element; determining a position of a second midpoint between the second front wall and the second rear wall in the illumination direction; Including, An angle of the tube with respect to the direction of irradiation of the ultrasonic wave is determined based on the position of the first intermediate point and the position of the second intermediate point. The method for processing biological information according to claim 1 .

9. The Doppler shift frequency is determined through a pulse Doppler method or a color Doppler method. The method for processing biological information according to claim 1 .

10. After two or more ultrasonic elements facing the pipe are identified, only the two or more ultrasonic elements facing the pipe are driven. The method for processing biological information according to claim 1 .

11. the fluid is blood or urine; The tube is a blood vessel or a ureter. The method for processing biological information according to claim 1 .

12. The ultrasonic sensor is attached to the neck of the subject, The vessel is the carotid artery. The method for processing biological information according to claim 11.

13. A program for causing a computer to execute the biometric information processing method according to claim 1 .

14. A biological information processing device configured to automatically acquire information related to a fluid flowing inside a subject's body using an ultrasonic sensor having a sheet and a plurality of ultrasonic elements arranged two-dimensionally on the sheet and each configured to emit ultrasonic waves toward biological tissue of the subject, The biometric information processing device includes: one or more processors; A memory for storing instructions; Equipped with The instructions, when executed by the processor, cause the biometric information processing device to: acquiring a plurality of ultrasonic reflection signals reflected by the biological tissue; Identifying two or more ultrasonic elements facing a pipe through which the fluid flows among the plurality of ultrasonic elements based on the plurality of reflected signals; by analyzing a reflected signal of ultrasonic waves associated with a first ultrasonic element of the two or more ultrasonic elements, a first position of a portion of the pipe facing the first ultrasonic element in an irradiation direction of the ultrasonic waves is identified; By analyzing a reflected signal of the ultrasonic wave associated with a second ultrasonic element of the two or more ultrasonic elements, a second position of the portion of the pipe facing the second ultrasonic element in the direction of irradiation of the ultrasonic wave is identified; determining an angle of the tube with respect to a direction of irradiation of the ultrasonic wave based on the first position and the second position; Analyzing a reflected signal of the ultrasonic wave associated with the first ultrasonic element or the second ultrasonic element to identify a Doppler shift frequency of the ultrasonic wave reflected by the fluid flowing in the pipe; obtaining information related to the fluid based at least on the tube angle and the Doppler shift frequency; Biometric information processing device.

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