JP2020199162A - Ultrasonic diagnostic apparatus and ultrasonic diagnostic apparatus control method - Google Patents

Abstract

To provide an ultrasonic diagnostic apparatus capable of adaptively improving the accuracy of propagation analysis of a shear wave according to calculation capability.SOLUTION: The ultrasonic diagnostic apparatus comprises: a push wave transmission unit for causing an ultrasonic probe to transmit a push wave; a detection wave transmission unit for causing the ultrasonic probe to transmit a detection wave which passes through a region of interest within a subject; a detection wave reception unit for generating acoustic line signals by receiving ultrasonic waves reflected from the region of interest in response to the detection wave by using the ultrasonic probe; and a mechanical property calculation unit which selects plural analytic target signals out of the plural acoustic line signals, and calculates the mechanical properties of an analytic target position, on the basis of the selected analytic target signals. A calculation circuit is detachable from the apparatus and includes a parameter calculation unit for calculating parameters for selecting the acoustic line signals on the basis of the plural acoustic line signals. While the calculation circuit is attached, the mechanical property calculation unit selects plural analytic target signals on the basis of the parameters.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to an ultrasonic diagnostic apparatus and a control method of the ultrasonic diagnostic apparatus, and more particularly to measurement of propagation velocity of a shear wave in a tissue using a shear wave and measurement of mechanical properties of the tissue.

The ultrasonic diagnostic apparatus transmits ultrasonic waves into the subject from a plurality of transducers constituting the ultrasonic probe, and receives an ultrasonic reflected wave (echo) generated by a difference in acoustic impedance of the subject tissue, which is obtained. It is a medical inspection device that generates and displays an ultrasonic tomographic image showing the structure of the internal tissue of a subject based on an electric signal.

In recent years, mechanical property measurement (SWSM; Shear Wave Speed Measurement, hereinafter referred to as "shear wave speed measurement") of a tissue applying this ultrasonic diagnostic technique has been widely used for inspection. Since the hardness of tumors found in organs and body tissues can be measured non-invasively and easily, the hardness of tumors can be examined in cancer screening tests and liver fibrosis in liver disease tests. It can be used for evaluation and is useful.

In this shear wave velocity measurement, a push wave (focused ultrasonic wave or ARFI; Acoustic Radiation Force Impulse) in which ultrasonic waves are focused on a specific part in a subject is transmitted from a plurality of transducers, and then ultrasonic waves for detection are transmitted. By repeating the transmission of ultrasonic waves (hereinafter referred to as "detection waves") and the reception of reflected waves multiple times, and measuring the propagation velocity of shear waves generated by the acoustic radiation pressure of push waves, the mechanical properties of the tissue can be measured. The propagation velocity of the represented shear wave can be calculated (for example, Patent Document 1).

JP-A-2018-38522

As a typical method for measuring the propagation velocity of a shear wave, the displacement in the direction orthogonal to the propagation direction of the shear wave is detected at a plurality of positions in the subject, and the time-series movement of the displacement peak position is the shear wave. There is a method to detect it as the movement of the wave surface. In order to improve the detection accuracy in this method, it is necessary to improve the detection accuracy of the peak time of the displacement and improve the detection accuracy of the displacement amount. However, in the subject, the signal quality of the acoustic line signal based on the reflected ultrasonic wave of the detected wave varies depending on the position. On the other hand, the amount of calculation for detecting the peak time of displacement increases in proportion to the number of observation points for which the acoustic line signal is generated, so hardware having high calculation processing capacity is required. However, in a portable ultrasonic diagnostic apparatus, for example, there are often restrictions on the improvement of computing power due to the size of the apparatus, exhaust heat, driveable time by a battery, and the like. On the other hand, when ultrasonic diagnostic devices having different computing powers are used depending on the application, the number of ultrasonic diagnostic devices increases, which is inefficient.

The present disclosure has been made in view of the above problems, and an object of the present disclosure is to provide an ultrasonic diagnostic apparatus capable of adaptively improving the measurement accuracy of the shear wave propagation velocity according to the computing power.

The ultrasonic diagnostic apparatus according to one aspect of the present disclosure includes an ultrasonic signal processing circuit and an arithmetic circuit configured to be detachable from the ultrasonic signal processing circuit, and the ultrasonic signal processing circuit is covered. A push wave transmitter that transmits a push wave for generating displacement in the sample to the ultrasonic probe, and a detection wave that passes through the region of interest including the analysis target position in the sample following the transmission of the push wave. A detection wave transmitter to be transmitted to the ultrasonic probe and a reception signal based on the ultrasonic wave reflected from the region of interest corresponding to the detection wave are received from the ultrasonic probe, and the interest is based on the received signal. A detection wave receiver that generates an ultrasonic signal by performing phase adjustment addition at a plurality of positions in the region, and a plurality of analysis target signals are selected from the plurality of the acoustic line signals, and based on the selected analysis target signal, The calculation circuit includes a mechanical characteristic calculation unit that calculates the mechanical characteristics of the analysis target position, and the calculation circuit calculates a parameter for selecting the analysis target signal based on the plurality of the acoustic line signals. When the arithmetic circuit is mounted on the ultrasonic signal processing circuit, the mechanical characteristic calculation unit is characterized in that a plurality of the analysis target signals are selected based on the parameters.

According to the present disclosure, when the arithmetic circuit is connected to the ultrasonic signal processing circuit, it is possible to select an acoustic line signal based on the parameters generated by the parameter calculation unit included in the arithmetic circuit according to the above configuration. Therefore, the measurement accuracy of the shear wave propagation velocity can be improved without increasing the calculation load of the ultrasonic signal processing circuit, and further, the measurement accuracy of the mechanical characteristics of the analysis target position can be improved.

It is a schematic diagram which shows the outline of the SWS sequence including the shear wave propagation analysis in the ultrasonic diagnostic apparatus 100 which concerns on Embodiment 1. FIG. It is a functional block diagram of the ultrasonic diagnostic system 1000 including the ultrasonic diagnostic apparatus 100. (A) is a schematic diagram showing the position of the transmission focal point F of the push wave generated by the push wave generation unit 103, and (b) is a schematic diagram showing the configuration outline of the detection wave pulse generated by the detection wave generation unit 104. is there. (A) is a functional block diagram showing the configuration of the transmitting beam former unit 105, and (b) is a functional block diagram showing the configuration of the receiving beam former unit 107. It is a schematic diagram which shows the outline of a push wave. (A) is a schematic diagram showing an outline of detection wave transmission, and (b) is a schematic diagram showing an outline of reflected wave reception. It is a schematic diagram which shows the outline of the calculation method of the propagation path of an ultrasonic wave in the delay processing unit 10731. (A) is a schematic diagram showing the relationship between the region of interest roi and the observation point candidate region Li, and (b) is a schematic diagram showing the relationship between the region of interest roi and the transmission event and the observation point candidate region Lti. It is a functional block diagram which shows the structure of the speed calculation unit 108 and the parameter calculation unit 111. It is a schematic diagram which shows the outline of the process of the integrated SWS sequence in the ultrasonic diagnostic apparatus 100. It is a flowchart which shows the operation of SWSM processing in an ultrasonic diagnostic apparatus 100. (A) to (c) are schematic views showing the state of the generation of the shear wave by the push wave pulse pp. (A) is a schematic diagram showing the relationship between the region of interest roi, the observation point candidate region Li, and the observation point Pij, and (b) to (d) are schematic diagrams showing the outline of the propagation analysis of the region of interest roi. It is a flowchart which shows the operation of SWSM processing when the arithmetic circuit 160 is not used in the ultrasonic diagnostic apparatus 100. It is a schematic diagram which shows the relationship between the region of interest roi and the observation point Pij when the arithmetic circuit 160 is not used in the ultrasonic diagnostic apparatus 100. It is a functional block diagram of the ultrasonic diagnostic system 2000 including the ultrasonic diagnostic apparatus 200. It is a functional block diagram which shows the structure of the map type speed calculation unit 261. It is a functional block diagram which shows the structure of the speed calculation unit 208, the map type speed calculation unit 261 and the parameter calculation unit 262. It is a flowchart which shows the operation of SWSM processing in an ultrasonic diagnostic apparatus 200. It is a flowchart which shows the operation of the shear wave propagation analysis processing in the map type velocity calculation unit 261. It is a schematic diagram which shows the operation of displacement detection and shear wave propagation analysis. It is a schematic diagram which shows each of the ultrasonic diagnostic system 3000, the portable main body part 300, and the cart 303 which concerns on Embodiment 3.

<< Background to the form for carrying out the invention >>
The inventor has made various studies on improving the accuracy by scalable control according to the computing power, especially in ultrasonic elasticity measurement by a portable ultrasonic diagnostic apparatus.

As described above, in ultrasonic elasticity measurement, a shear wave is excited in a subject by a push wave, and the mechanical characteristics are calculated by measuring the propagation velocity of the shear wave. Therefore, in ultrasonic elasticity measurement, the displacement in the subject is detected by repeatedly transmitting and receiving the detection wave following the transmission of the push wave, and the position of the wave surface of the shear wave is analyzed by analyzing the time-series change. To estimate. Then, the moving speed of the wave surface is calculated as the moving speed of the shear wave. As one of the methods for calculating the velocity of the shear wave, a plurality of observation points are provided in the subject, and the time when the displacement amount becomes the maximum (peak) at each observation point (hereinafter referred to as "peak time") is set. There is a method of detecting and assuming that the observation point has passed the wave front of the shear wave at the peak time. In this method, in particular, in so-called point-type measurement in which the region of interest is narrowed and the average propagation velocity of the entire region of interest is calculated, the number of observation points is limited, so that the amount of calculation is small and the shear wave It has a characteristic of high resolution of moving speed and is suitable for absolute evaluation of mechanical characteristics. On the other hand, in the method using such a small number of observation points, the signal quality such as the signal level, noise level, and signal-to-noise ratio (SNR) of the acoustic line signal based on the reflection detection wave from the observation point is improved. , It tends to affect the reliability of the moving speed of the shear wave as it is.

As another method of calculating the shear wave velocity, a large number of observation points are provided in the subject, and the wave surface of the shear wave at each time is detected based on the spatial distribution of the displacement measured at each observation point. , There is a method to directly analyze the time-series change of the wave surface position of the shear wave. In this method, in so-called map-type measurement, which analyzes the spatial distribution of propagation velocity in a wide area of interest, the spatial distribution of mechanical properties can be obtained and the source of shear wave reflection can be obtained by providing a large number of observation points. It is suitable for obtaining a reliability map of the moving speed of shear waves based on the position of a refraction source or the like. On the other hand, this method requires a large amount of calculation because there are many observation points, and the moving speed of the shear wave is obtained mechanically from the overall tendency and statistical properties of the measurement results of many observation points. Not suitable for absolute evaluation of characteristics.

Therefore, the inventor selects the position of the observation point in the point-type measurement when the computing power can be improved by a removable arithmetic circuit or the like based on the so-called point-type measurement in which the amount of arithmetic is small. With the idea of generating the above information by the arithmetic circuit, the ultrasonic diagnostic apparatus according to the present disclosure and the control method of the ultrasonic diagnostic apparatus have been conceived.

Hereinafter, the ultrasonic diagnostic apparatus and the control method thereof according to the embodiment will be described in detail with reference to the drawings.

<< Embodiment 1 >>
The ultrasonic diagnostic apparatus 100 performs a process of calculating the propagation velocity of a shear wave representing the mechanical characteristics of a tissue by a shear wave velocity measuring method. FIG. 1 is a schematic view showing an outline of a SWS sequence by a shear wave velocity measurement method in an ultrasonic diagnostic apparatus 100. As shown in the central frame of FIG. 1, the processing of the ultrasonic diagnostic apparatus 100 is, for example, "reference detection wave pulse transmission / reception", "push wave pulse transmission", "detection wave pulse transmission / reception", and "mechanical characteristic calculation". It consists of processes. In the embodiment described below, the step of "mechanical characteristic calculation" is carried out based on the step of "reference detection wave pulse transmission / reception" and the step of "detection wave pulse transmission / reception". The "mechanical characteristic calculation" step may be performed based only on the "pulse transmission / reception" step, and in this case, the "reference detection wave pulse transmission / reception" step may not be performed.

In the step of "reference detection wave pulse transmission / reception", the reference detection wave pulse pwp0 is transmitted to the ultrasonic probe, and the detection wave pw0 is transmitted and the reflected wave to a range corresponding to the region of interest roi in the subject to a plurality of oscillators. The reception of the ec is performed to generate an acoustic line signal that serves as a reference for the initial position of the tissue.

In the process of "push wave pulse transmission", the push wave pulse ppp is transmitted to the ultrasonic probe, and the push wave pp in which the ultrasonic waves are converged is transmitted to a specific part in the subject by a plurality of oscillators, which is of interest. Excites shear waves that pass through the region roi.

After that, in the process of "detection wave pulse transmission / reception", the detection wave pulse pwpl is transmitted to the ultrasonic probe, and the detection wave pwl is transmitted to the plurality of vibrators and the reflected wave ec is received multiple times. The propagation state of the shear wave in the region roi is measured. In the step of "calculation of mechanical characteristics", first, the displacement distribution pt1 of the structure due to the propagation of the shear wave is calculated in time series, and then the mechanical characteristics of the structure are expressed from the time-series changes of the displacement distribution pt1. Shear wave propagation velocity is calculated. Shear wave propagation velocity is measured, and finally, the mechanical characteristics are displayed.

The series of steps associated with the excitation of one shear wave based on the push wave pp transmission shown above is called a "SWS sequence" (SWS: Shear Wave Speed).

<Ultrasonic diagnostic system 1000>
1. 1. Outline of the device An ultrasonic diagnostic system 1000 including the ultrasonic diagnostic device 100 according to the first embodiment will be described with reference to the drawings. FIG. 2 is a functional block diagram of the ultrasonic diagnostic system 1000 according to the first embodiment. As shown in FIG. 2, the ultrasonic diagnostic system 1000 transmits ultrasonic waves toward a subject and receives the reflected waves of a plurality of ultrasonic vibrators (transmuter trains) 101a arranged in a row on the tip surface. An ultrasonic probe 101 (hereinafter referred to as "probe 101"), an ultrasonic diagnostic apparatus 100 that causes the probe 101 to transmit and receive ultrasonic waves and generate an ultrasonic signal based on an output signal from the probe 101, and an operation input from an inspector. It has an operation input unit 102 for receiving the above and a display unit 114 for displaying an ultrasonic image on the screen. The probe 101, the operation input unit 102, and the display unit 114 are each configured to be connectable to the ultrasonic diagnostic apparatus 100.

Next, each element externally connected to the ultrasonic diagnostic apparatus 100 will be described.

2. 2. Probe 101
The probe 101 has, for example, an oscillator sequence (101a) composed of a plurality of oscillators 101a arranged in a straight line. The probe 101 converts a pulse-shaped electric signal (hereinafter referred to as “transmission signal”) supplied from the transmission beam former unit 105, which will be described later, into a pulse-shaped ultrasonic wave. The probe 101 transmits an ultrasonic beam composed of a plurality of ultrasonic waves emitted from a plurality of vibrators toward a measurement target in a state where the surface of the vibrator 101 of the probe 101 is applied to the surface of a subject via an ultrasonic gel or the like. To do. Then, the probe 101 receives a plurality of reflected detection waves (hereinafter referred to as “reflected waves”) from the subject, converts each of these reflected waves into an electric signal by the plurality of oscillators 101a, and is an ultrasonic diagnostic apparatus. Supply to 100.

3. 3. Operation input unit 102
The operation input unit 102 receives various operation inputs such as various settings and operations for the ultrasonic diagnostic apparatus 100 from the inspector, and outputs them to the control unit 113 of the ultrasonic diagnostic apparatus 100.

The operation input unit 102 may be, for example, a touch panel integrally configured with the display unit 114. In this case, various settings and operations of the ultrasonic diagnostic apparatus 100 can be performed by performing a touch operation or a drag operation on the operation keys displayed on the display unit 114, and the ultrasonic diagnostic apparatus 100 is operated by this touch panel. It is configured to be possible. Further, the operation input unit 102 may be, for example, a keyboard having keys for various operations, an operation panel having buttons, levers, or the like for various operations, a mouse, or the like.

<Outline of configuration of ultrasonic diagnostic apparatus 100>
Next, the ultrasonic diagnostic apparatus 100 according to the first embodiment will be described.

The ultrasonic diagnostic apparatus 100 selects a vibrator to be used for transmission or reception from among the plurality of vibrators 101a of the probe 101, and secures input / output to the selected vibrator. Based on the transmission beamformer unit 105 that controls the timing of high voltage application to each vibrator 101a of the probe 101 and the reflected wave received by the probe 101, the reception beamforming is performed to generate an acoustic wave signal. It has a receiving beamformer unit 107.

Further, it has a push wave generation unit 103 for transmitting a push wave pulse ppp to a plurality of oscillators 101a, and a detection wave generation unit 104 for transmitting a detection wave pulse pwpl a plurality of (m) times following the push wave pulse ppp.

Further, a speed calculation unit 108 that measures the propagation velocity of the shear wave in the region of interest roi based on the acoustic line signal output by the reception beam former unit 107, a data storage unit 109 that stores the acoustic line signal, and a B mode from the acoustic line signal. B-mode image generation unit 110 that generates an image, parameter calculation unit 111 that generates parameters for the speed calculation unit 108 to measure the propagation speed of shear waves based on the acoustic line signal, B-mode image and propagation speed measurement result A display control unit 112 that configures a display image from at least one of them and displays it on the display unit 114, and a region of interest roi that represents an analysis target range in the subject based on the operation input from the operation input unit 102 are set, and each of them is set. A control unit 113 for controlling the components is provided.

Of these, the multiplexer section 106, transmission beam former section 105, reception beam former section 107, push wave generation section 103, detection wave generation section 104, speed calculation section 108, and control section 113 constitute an ultrasonic signal processing circuit 150. .. Further, the parameter calculation unit 111 constitutes the arithmetic circuit 160.

Each element constituting the ultrasonic signal processing circuit 150, for example, the transmission beam former unit 105 and the speed calculation unit 108, is a hardware circuit such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit), respectively. Is realized by. Alternatively, the configuration may be realized by a processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit) and software, and a configuration using a GPU is particularly referred to as a GPGPU (General-Purpose computing on Graphics Processing Unit). be called. These components can be a single circuit component, or can be an aggregate of a plurality of circuit components. Further, a plurality of components can be combined into one circuit component, or an aggregate of a plurality of circuit components can be formed. Further, the arithmetic circuit 160 is composed of, for example, a GPGPU, and is realized by a GPU, a memory, a power supply, and software that operates the GPU.

The data storage unit 109 is a computer-readable recording medium, and for example, a flexible disk, a hard disk, an MO, a DVD, a BD, a semiconductor memory, or the like can be used. Further, the data storage unit 109 may be a storage device connected to the ultrasonic diagnostic apparatus 100.

The ultrasonic diagnostic apparatus 100 according to the embodiment is not limited to the ultrasonic diagnostic apparatus having the configuration shown in FIG. For example, the multiplexer section 106 may not be required, or the probe 101 may include a transmission beam former section 105, a reception beam former section 107, or a part thereof.

<Structure of each part of ultrasonic diagnostic apparatus 100>
Next, the configuration of each block included in the ultrasonic diagnostic apparatus 100 will be described.

1. 1. Control unit 113
Generally, in a state where a B-mode image, which is a tomographic image of a subject acquired by the probe 101 in real time, is displayed on the display unit 114, the operator uses the B-mode image displayed on the display unit 114 as an index. , The analysis target position in the subject is specified and input to the operation input unit 102. The control unit 113 sets the area of interest roi, which is the analysis target range, by inputting the information specified by the operator from the operation input unit 102. Here, since the mechanical property of the subject acquires one value for the entire area of interest roi, it is preferable that the area of interest roi is in a narrow range so that the mechanical property does not change significantly inside the area roi. Alternatively, the control unit 113 may set the region of interest roi based on the position of the oscillator train (101a) composed of the plurality of oscillators 101a on the probe 101. For example, the region of interest roi may be set in the front direction of the oscillator 101a slightly away from the center of the oscillator train (101a) composed of the plurality of oscillators 101a.

Further, the control unit 113 controls other blocks of the ultrasonic diagnostic apparatus 100, which will be described later, based on a command from the operation input unit 102. Further, the control unit 113 determines whether or not the arithmetic circuit 160 can be used, and changes the control contents of other blocks according to the determination result.

2. 2. Push wave generator 103
The push wave generation unit 103 acquires information indicating the region of interest roi from the control unit 113, and sets a specific point in the vicinity of the region of interest roi. Then, by causing the plurality of oscillators 101a to transmit the push wave pulse ppp from the transmission beam former unit 105, the plurality of oscillators 101a are in the subject corresponding to a specific point (hereinafter, referred to as “transmission focus FP”). A push wave pp in which the ultrasonic beam is focused is transmitted to a specific part of the. As a result, a shear wave is excited at a specific site in the subject.

Specifically, the push wave generation unit 103 transmits the position of the transmission focal point FP of the push wave and the push wave ppp based on the information indicating the region of interest roi (hereinafter, “push wave transmission oscillator sequence Px”). ”) Is determined as shown below.

FIG. 3A is a schematic diagram showing the position of the transmission focal point FP of the push wave ppp generated by the push wave generation unit 103. The length w in the row direction and the length h in the depth direction of the subject of the region of interest roi are equal to or less than the length a in the row direction and the length b in the depth direction of the subject in the ultrasonic irradiation range by the plane wave, respectively. The case where the region of interest roi is set near the center of the irradiation range will be described as an example. In the present embodiment, as shown in FIG. 3A, the column-direction transmission focus position fx of the transmission focus FP coincides with the column-direction center position wc of the region of interest roi.

Further, the push wave transmission oscillator sequence Px is set based on the transmission focal position fz in the depth direction. In the present embodiment, the length of the push wave pulse transmission oscillator train Px is set to the length a of all the rows of the plurality of oscillators 101a.

The information indicating the position of the transmission focus FP and the push wave transmission oscillator train Px is output to the transmission beam former unit 105 as a transmission control signal together with the pulse width PW of the push pulse ppp and the application start time PT. Further, the time interval PI of the application start time PT may be included. The pulse width PW of the push wave pulse ppp, the application start time PT, and the time interval PI will be described later.

The positional relationship between the region of interest roi and the transmission focus FP is not limited to the above, and may be appropriately changed depending on the shape of the part to be inspected of the subject.

For example, in the example shown in FIG. 3A, the column-direction transmission focus position fx of the transmission focus FP positions is offset from the column-direction center position wc of the region of interest roi in the positive or negative direction of the x-axis. You may change it. In this case, the width w of the region of interest and the center of the oscillator train in the column direction have different configurations. Further, the columnwise focal position fx of the transmission focal point FP may be offset from the columnwise center wc of the region of interest roi in the positive or negative direction of the x-axis and located outside the region of interest roi.

Further, the transmission focus FP may be set at a predetermined position near the region of interest roi and outside the region of interest roi. At this time, when the transmission focus FP is set in the vicinity of the region of interest roi, the transmission focus FP is set at a distance that the shear wave can reach the region of interest roi with respect to the region of interest roi.

Note that the "focusing" of the ultrasonic beam by the push wave means that the ultrasonic beam is focused and is a focus beam, that is, the area irradiated by the ultrasonic beam decreases after transmission and the minimum value is set at a specific depth. It refers to taking, and is not limited to the case where the ultrasonic beam is focused on one point. In this case, the “transmission focal point FP” refers to the center of the ultrasonic beam at the depth at which the ultrasonic beam is focused.

The information indicating the position of the transmission focus F and the push wave transmission oscillator train Px is output to the transmission beam former unit 105 as a transmission control signal together with the pulse width of the push wave pulse ppp.

3. 3. Detection wave generator 104
The detection wave generation unit 104 inputs information indicating the region of interest roi from the control unit 113, and causes a plurality of oscillators 101a to transmit the detection wave pulse pwpl from the transmission beam former unit 105 a plurality of times so that the ultrasonic beam is in the region of interest. The detection wave pw is transmitted to a plurality of oscillators 101a belonging to the detection wave pulse transmission oscillator train Tx so as to pass through the roi. Specifically, the detection wave generation unit 104 transmits a detection wave pulse pwpl so that the ultrasonic beam passes through the region of interest roi based on the information indicating the region of interest roi (hereinafter, “detection wave transmission”). The oscillator train Tx ”) is determined.

FIG. 3B is a schematic diagram showing an outline of the configuration of the detection wave pulse pwpl generated by the detection wave generation unit 104. As shown in FIG. 3B, the detection wave generation unit 104 transmits the detection wave pulse so that the detection wave, which is a so-called plane wave in which the detection wave pulse transmission oscillator is driven in the same phase, passes through the entire roi of interest. The oscillator train Tx is set. The length a of the detection wave pulse transmission oscillator sequence Tx is preferably set to be larger than the width of interest region w. In this example, the detection wave pulse transmission oscillator sequence Tx is set so that both ends are located outward by a predetermined distance from the region of interest roi, with the center in the x direction as the column direction transmission focus position fx of the transmission focus FP. To. Since the detection wave pw is a plane wave, it propagates in the Z direction perpendicular to the oscillator train direction. Therefore, the region of interest roi is included in the ultrasonic irradiation region Ax with margins at both ends in the X direction. From this, the acoustic line signal can be generated for the observation points in the entire interest region roi by transmitting and receiving the detection wave once, and the detection wave pulse pwpl is transmitted so that the ultrasonic beam surely passes through the entire interest region roi. can do.

The traveling direction of the ultrasonic beam, which is the detection wave, is not limited to the Z direction, and may be set so as to travel in a direction forming a predetermined azimuth angle θ with respect to the Z direction.

4. Transmission beam former unit 105
The transmission beam former unit 105 is connected to the probe 101 via a multiplexer unit 106, and push wave transmission vibration that hits all or a part of a plurality of oscillators 101a existing in the probe 101 in order to transmit ultrasonic waves from the probe 101. This is a circuit that controls the timing of high voltage application to each of a plurality of oscillators included in the child train Px or the detection wave transmission oscillator train Tx.

FIG. 4A is a functional block diagram showing the configuration of the transmission beam former unit 105. As shown in FIG. 4A, the transmission beam former unit 105 includes a drive signal generation unit 1051, a delay profile generation unit 1052, and a drive signal transmission unit 1053.

(1) Drive signal generator 1051
The drive signal generation unit 1051 is a transmission control signal from the push wave generation unit 103 or the detection wave generation unit 104, which is information indicating the push wave transmission oscillator train Px or the detection wave transmission oscillator train Tx, the push wave pulse ppp. Based on each of the pulse width PW, the information indicating the application start time PT, the pulse width of the detection wave pulse pwpl, and the information indicating the application start time, from the transmission oscillator corresponding to a part or all of the oscillator 101a existing in the probe 101. This is a circuit that generates a pulse signal sp for transmitting an ultrasonic beam.

(2) Delay profile generator 1052
In the delay profile generation unit 1052, among the transmission control signals obtained from the push wave generation unit 103, the application that determines the transmission timing of the ultrasonic beam is determined based on the information indicating the position of the push wave transmission oscillator train Px and the transmission focus FP. This circuit sets and outputs the delay time tppk (k is a natural number from 1 to the number kmax of the oscillator 101a) for each oscillator from the start time PT. Further, the delay profile generation unit 1052 determines the transmission timing of the ultrasonic beam based on the information indicating the detection wave transmission oscillator train Tx among the transmission control signals obtained from the detection wave generation unit 104, from the application start time PT. The delay time tptk (k is a natural number from 1 to the number kmax of the oscillator 101a) is set for each oscillator and output. As a result, the transmission of the ultrasonic beam is delayed for each oscillator by the delay time, and the ultrasonic beam is focused. The delay time tptk may be tptk = 0 for all k.

(3) Drive signal transmitter 1053
The drive signal transmission unit 1053 has a plurality of vibrators existing in the probe 101 as shown in the schematic diagram of FIG. 5 based on the pulse signal sp from the drive signal generation unit 1051 and the delay time tppk from the delay profile generation unit 1052. In 101a, a push wave transmission process for supplying a push wave pulse ppp for transmitting a push wave to each oscillator included in the push wave transmission oscillator train Px is performed. The push wave transmission oscillator sequence Px is selected by the multiplexer section 106.

A push wave that causes physical displacement in a living body is required to have a significantly larger power than a transmission pulse used for a normal B mode display or the like. That is, the drive voltage applied to the pulsar (ultrasonic generator) may be normally 30 to 40 V in the acquisition of the B mode image, whereas the push wave requires, for example, 50 V or more. Further, in the acquisition of the B mode image, the transmission pulse length is about several μsec, but the push wave may require a transmission pulse length of several hundred μsec per transmission.

In the present embodiment, as shown in the schematic diagram of FIG. 6A, the push wave pulse ppp is transmitted from the drive signal transmission unit 1053 to the plurality of oscillators 101a at the application start time PT. The push wave pulse ppp is composed of a burst signal having a predetermined pulse width PW (time length), a predetermined voltage amplitude (+ V to −V), and a predetermined frequency. Specifically, the pulse width PW may be, for example, 100 to 200 μsec, the frequency may be, for example, 6 MHz, and the voltage amplitude may be, for example, + 50 V to −50 V. However, it goes without saying that the application conditions are not limited to the above.

Further, the drive signal transmission unit 1053 supplies a detection wave pulse pwpl for transmitting an ultrasonic beam to each of the oscillators included in the detection wave transmission oscillator train Tx among the plurality of oscillators 101a existing in the probe 101. Perform wave transmission processing. The detection wave transmission oscillator sequence Tx is selected by the multiplexer section 106. However, the configuration related to the supply of the detection wave pulse pwpl is not limited to the above, and for example, the configuration may not use the multiplexer section 106.

After transmitting the push wave pulse ppp, the transmission beam former unit 105 transmits the detection wave pulse pwpl a plurality of times based on the transmission control signal from the detection wave generation unit 104. After one push wave pulse ppp transmission, each time of a series of detection wave pulse pwpl transmissions performed a plurality of times from the same detection wave transmission oscillator sequence Tx is referred to as a "transmission event".

5. Receive beam former unit 107
As shown in FIG. 8A, the receiving beam former unit 107 sets a plurality of observation point candidate regions Li arranged in the x direction in the region of interest roi shown in the schematic diagram of FIG. 3B, and observes the region. This is a circuit for setting a plurality of reference points Rij in each of the point candidate regions Li. Here, the observation point candidate region Li is, for example, a region on a straight line extending in the z direction, and is arranged at equal intervals in the x direction. Further, the reference points Rij are arranged at equal intervals in the z direction, for example. The reception beam former unit 107 further exists in the region of interest roi based on the reflected waves from the subject tissue received in time series by the plurality of vibrators 101a corresponding to each of the plurality of detection wave pulses pwpl. Generates an acoustic line signal for a plurality of reference points Rij to generate a sequence of acoustic line signal frame data dsl (l is a natural number from 1 to m, and if the numbers are not distinguished, the acoustic line signal frame data dsl is used). It is a circuit. That is, after transmitting the detection wave pulse pwpl, the reception beam former unit 107 generates an acoustic line signal from the electric signals obtained by the plurality of oscillators 101a based on the reflected wave received by the probe 101. Here, i is a natural number indicating the order in the x direction in a plurality of observation point candidate regions Li in the region of interest roi, and j is a natural number indicating the order in the z direction in the reference point Rij on one observation point candidate region Li. is there. The "acoustic line signal" is a signal obtained by phase-adjusting and adding a received signal (RF signal).

FIG. 4B is a functional block diagram showing the configuration of the reception beam former unit 107. The receiving beam former unit 107 includes an input unit 1071, a received signal holding unit 1072, and a phase adjusting addition unit 1073.

(1) Input unit 1071
The input unit 1071 is a circuit that is connected to the probe 101 via a multiplexer unit 106 and generates a received signal (RF signal) based on the reflected wave in the probe 101. Here, the received signal rfk (k is a natural number from 1 to n) is an electric signal converted from the reflected wave received by each oscillator based on the transmission of the detection wave pulse pwpl. It is a so-called RF signal that has been D-converted, and the received signal rfk is a sequence of signals (received signal sequence) connected in the transmission direction (depth direction of the subject) of the ultrasonic waves received by each received oscillator rwk. It is composed of.

The input unit 1071 generates a sequence of received signal rfk for each received oscillator rwk for each transmission event based on the reflected wave obtained by each of the receiver oscillators rwk. The wave receiving oscillator sequence is composed of oscillator sequences corresponding to a part or all of the plurality of oscillators 101a existing in the probe 101, and is selected by the multiplexer unit 106 based on an instruction from the control unit 113. In this example, all of the plurality of oscillators 101a are selected as the wave receiving oscillator train. As a result, as shown in FIG. 6 (b) showing the outline of the reflection detection wave reception, the reflected waves from the observation points existing in the entire detection wave irradiation region Ax by one reception processing are used by all the oscillators. It is possible to receive a wave and generate a wave receiving oscillator train for all the oscillators. The generated received signal rfk is output to the received signal holding unit 1072.

(2) Received signal holding unit 1072
The received signal holding unit 1072 is a computer-readable recording medium, and for example, a semiconductor memory or the like can be used. The received signal holding unit 1072 inputs the received signal rfk for each receiving oscillator rwk from the input unit 1071 in synchronization with the transmission event, and holds this until one acoustic line signal frame data is generated. To do.

The received signal holding unit 1072 may be a part of the data storage unit 109.

(3) Phase adjustment addition unit 1073
In the phasing addition unit 1073, the receiving oscillator Rpk included in the detection wave pulse receiving oscillator sequence Rx is set for each of the reference points Rij existing on the observation point candidate region Li in the region of interest roi in synchronization with the transmission event. This is a circuit that generates an acoustic line signal ds by adding delay processing to the received received signal rfk and then adding all the received oscillators Rpk. Here, as shown in FIG. 8A, the observation point candidate regions Li are arranged at equal intervals in the column direction (x direction), and the reference points Rij are uniformly arranged in the depth direction (z direction). Is preferable. Specifically, the reference points Rij are arranged at equal intervals in the x direction on the observation point candidate region Li extending in the column direction (x direction). The detection wave pulse receiving oscillator train Rx is composed of a receiving oscillator Rpk which is a part or all of a plurality of oscillators 101a existing in the probe 101, and is a phase adjusting addition unit 1073 and a multiplexer unit based on an instruction from the control unit 113. Selected by 106. In this example, as the reflected wave receiving oscillator sequence Rx, an oscillator sequence including at least all the oscillators constituting the detection wave pulse transmitting oscillator train Tx in each transmission event is selected.

The phase-adjusting addition unit 1073 includes a delay processing unit 10731 and an addition unit 10732 for processing the received signal rfk.

a) Delay processing unit 10731
The delay processing unit 10731 receives the received signal rfk for the receiving oscillator Rpk in the detection wave pulse receiving oscillator train Rx by dividing the difference in distance between the reference point Rij and each of the receiving oscillators Rpk by the sound velocity value. This is a circuit that compensates for the arrival time difference (delay amount) of the reflected ultrasonic waves to each of the oscillators Rpk and identifies them as a received signal corresponding to the received oscillator Rpk based on the reflected ultrasonic waves from the reference point Rij.

FIG. 7 is a schematic diagram showing an outline of a calculation method of an ultrasonic wave propagation path in the delay processing unit 10731. The propagation path of ultrasonic waves emitted from the detection wave pulse transmission oscillator train Tx, reflected at the reference point Rij at an arbitrary position in the region of interest roi, and reaching the reception oscillator Rpk is shown.

-Calculation of transmission time The delay processing unit 10731 calculates the transmission time by specifying the transmission route to the reference point Rij in response to the transmission event and dividing the distance by the speed of sound. The transmission path may be, for example, a linear path from the center of the detection wave transmission oscillator sequence Tx to the reference point Rij. The transmission path is not limited to this, and may be, for example, the shortest path from the center of the detection wave transmission oscillator sequence Tx to an arbitrary point having the same depth as the reference point Rij.

-Calculation of reception time The delay processing unit 10731 specifies the reception path for the reference point Rij until it reaches the reception oscillator that is reflected at the reference point Rij and is included in the detection wave receiver oscillator sequence in response to the transmission event. Then, the transmission time is calculated by dividing the distance by the speed of sound. The receiving path may be, for example, a linear path from the reference point Rij to the receiving oscillator.

-Calculation of delay amount Next, the delay processing unit 10731 calculates the total propagation time to each receiving oscillator from the transmission time and the reception time, and based on the total propagation time, the received signal for each receiving oscillator. Calculate the amount of delay applied to the column rfk.

Delay processing Next, the delay processing unit 10731 refers to the received signal rfk corresponding to the delay amount (the received signal corresponding to the time obtained by subtracting the delay amount) from the received signal sequence rfk for each receiving oscillator. It is identified as a signal corresponding to the receiving oscillator based on the reflected wave from the point Rij.

In response to the transmission event, the delay processing unit 10731 receives the received signal rfk from the received signal holding unit 1072 as an input, and receives the waves for each receiving oscillator Rpk for all the reference points Rij located in the region of interest roi. Identify the signal rfk.

b) Adder 10732
The addition unit 10732 takes the received signal rfk identified corresponding to the receiving oscillator Rpk output from the delay processing unit 10731 as an input, adds them, and adds the phasing to the reference point Rij. This is a circuit that generates dsij.

Further, the received signal rfk identified corresponding to each receiving oscillator Rpk may be multiplied by a receiving apodization (weight sequence) and then added to generate an acoustic line signal dsij with respect to the reference point Rij. The reception apodization is a sequence of weighting coefficients applied to the reception signal corresponding to the reception oscillator Rpk in the detection wave receiver sequence Rx. The received apodization is set so that, for example, the weight for the vibrator located at the center of the detection wave receiving oscillator row Rx in the column direction is maximized, and the central axis of the distribution of the received apodization is the detection wave receiving oscillator row central axis Rxo. Consistent with, the distribution has a shape symmetric with respect to the central axis. The shape of the distribution is not particularly limited. The reception apodization is not limited to the above case, and may be set so that, for example, the weight of the transmission oscillator sequence Tx with respect to the oscillator located at the center in the column direction is maximized.

The addition unit 10732 generates the acoustic line signal dsij for all the reference points Rij existing in the region of interest roi, and generates the acoustic line signal frame data dsl.

Then, the transmission and reception of the detection wave pulse pwpl are repeated in synchronization with the transmission event, and the acoustic line signal frame data dsl for all the transmission events is generated. The generated acoustic line signal frame data dsl is output to and stored in the data storage unit 109 for each transmission event.

6. Speed calculation unit 108 and parameter calculation unit 111
The velocity calculation unit 108 selects a plurality of observation point candidate regions Li based on the acoustic line signal corresponding to the reference point Rij, sets observation points Pij in each of the selected observation point candidate regions Li, and makes the set observations. It is a circuit that detects the displacement of the tissue in the region of interest roi from the sequence of the acoustic line signal frame data dsl for the point Pij and calculates the velocity of the shear wave.

Further, the parameter calculation unit 111 is a circuit that calculates a parameter as an index for selecting the observation point Pij from the sequence of the acoustic line signal frame data dsl.

FIG. 9 is a functional block diagram showing the configurations of the speed calculation unit 108 and the parameter calculation unit 111. The speed calculation unit 108 includes an observation point setting unit 1081, a displacement detection unit 1082, an arrival time detection unit 1083, a propagation speed conversion unit 1084, and a mechanical characteristic conversion unit 1085. The parameter calculation unit 111 includes a signal quality determination unit 1111.

(1) Signal quality determination unit 1111
The signal quality determination unit 1111 acquires a sequence of acoustic line signal frame data dsl from the reception beam former unit 107, and calculates the signal level and / or the noise level for each observation point candidate region Li. Then, the signal level and / or the noise level is output as the acoustic line signal quality data qlt for each observation point candidate region Li. When the signal level is output as the acoustic line signal quality data qlt, the signal quality determination unit 1111, for example, as shown in FIG. 8A, for each of the observation point candidate regions Li, the signal level of each of the plurality of reference points Rij. Is extracted, and then the representative value of the signal level for each observation point candidate region Li is output. As the representative value, for example, the maximum value, the median value, the average value, and the minimum value of the signal level can be used. More specifically, for example, for the observation point candidate region L1, the signal levels of each of the plurality of reference points R11, R12, R13, ..., R1j _max are extracted, and the average value is used as the signal level of the observation point candidate region L1. .. Similarly, for example, for the observation point candidate region L2, the signal levels of each of the plurality of reference points R21, R22, R23, ..., R2j _max are extracted, and the average value is used as the signal level of the observation point candidate region L1. Alternatively, for acoustic line signals related to a plurality of transmission events, for example, for a plurality of transmission events, for each observation point candidate region Lti, for each transmission event and as a reference point. After extracting the signal level for each Rij, the representative value of the signal level for each observation point candidate region Lti may be output. Here, the t-axis of FIG. 8B indicates a transmission event, and the two reference points Rijt ₁ and Rijt ₂ in which the x-coordinate and the z-coordinate are the same but the t-coordinates are different correspond to spatially the same positions. The acoustic line signals acquired from the reference points Rij by different transmission events t ₁ and t ₂ are shown as virtually different reference points. More specifically, for example, for the observation point candidate region Lt1, the signal levels of each of the plurality of reference points R111, R121, R112, R122, ..., R11t _max , and R12t _max are extracted, and the average value is used as the observation point candidate region L1. The signal level of. When using acoustic line signal data related to a plurality of transmission events, the number of reference points Rij does not necessarily have to be a plurality, and may be one for each observation point candidate region Li.

Further, when the noise level is output as the acoustic line signal quality data qlt, the signal quality determination unit 1111 is, for example, as shown in FIG. 8A, for each of the observation point candidate regions Li, for each of the plurality of reference points Rij. After extracting the signal level, a value indicating the non-uniformity of the signal level for each observation point candidate region Li is output. As the value indicating the non-uniformity of the signal level, for example, the variance of the signal level, the standard deviation, the sum of the absolute values of the differences between the signal levels and the average signal levels, and the difference between the maximum value and the minimum value can be used. .. More specifically, for example, for the observation point candidate region L1, the signal levels of each of the plurality of reference points R11, R12, R13, ..., R1j _max are extracted, and the standard deviation is used as the noise level of the observation point candidate region L1. .. Alternatively, for example, as shown in FIG. 8B, after extracting the signal level for each transmission event and each reference point Rij for each observation point candidate region Lti for a plurality of transmission events, the observation point A value indicating the non-uniformity of the signal level for each candidate region Lti may be output. More specifically, for example, for the observation point candidate region Lt1, the signal levels of each of the plurality of reference points R111, R121, R112, R122, ..., R11t _max , and R12t _max are extracted, and the standard deviation is set as the observation point candidate region L1. The noise level of. When using acoustic line signal data related to a plurality of transmission events, the number of reference points Rij does not necessarily have to be a plurality, and may be one for each observation point candidate region Li. The parameter calculation unit 111 may calculate the signal-to-noise ratio for each observation point candidate region Li and output it as acoustic line signal quality data qlt.

The acoustic line signal quality data qlt is not limited to the signal level, noise level, and signal-to-noise ratio, and any value may be used as long as it is a parameter indicating the quality of the acoustic line signal corresponding to the observation point candidate region Li. ..

The signal quality determination unit 1111 outputs the calculated acoustic line signal quality data qlt to the observation point setting unit 1081 of the speed calculation unit 108.

(2) Observation point setting unit 1081
The observation point setting unit 1081 selects the observation point Pij from the observation point candidate region Li based on the acoustic line signal quality data qlt. More specifically, as shown in FIG. 13A, for example, the observation point setting unit 1081 selects a predetermined number of observation point candidate regions Li in order from the one having the best signal-to-noise ratio. Here, the observation point candidate regions L3, L7, and L10 are selected. Then, one observation point Pij is set on each of the selected observation point candidate regions Li. Regarding the observation points Pij, i indicates the order of the plurality of observation points Pij in the region of interest roi in the x direction, and j indicates the order in the z direction. That is, for the same i, the i of the observation point candidate region Li and the i of the observation point Pij do not always match. In this example, observation points P ₁₁ , P ₁₂ , and P ₁₃ are set in the observation point candidate regions L3, L7, and L10, respectively. The selection criteria for the observation point candidate region Li are not limited to those described above, and for example, they may be selected in order from the one with the highest signal level, or may be selected in order from the one with the lowest noise level. Alternatively, for example, the observation point candidate region Li whose signal level is equal to or higher than a predetermined reference may be extracted and selected from the observation point candidate regions Li in descending order of signal-to-noise ratio. Further, the observation point candidate region Li may be selected so that the distance in the x direction is equal to or larger than a predetermined distance and the signal-to-noise ratio is high.

(3) Displacement detection unit 1082
For each of the observation points Pij, the displacement detection unit 1082 has one frame of acoustic line signal frame data dsl included in the sequence of acoustic line signal frame data dsl and reference acoustic line signal frame data (reference acoustic line signal frame data). ) Get ds0 and. The reference acoustic line signal frame data ds0 is a reference signal for extracting the displacement due to the shear wave in the acoustic line signal frame data dsl corresponding to each transmission event, and specifically, before the push wave pulse ppp transmission. It is the frame data of the acoustic line signal acquired from the region of interest roi. The displacement detection unit 1082 detects the displacement of each observation point Pij from the difference between the acoustic line signal frame data dsl and the reference acoustic line signal frame data ds0. Then, the displacement detection unit 1082 repeats this process to create time-series data of the displacement of each observation point Pij.

The displacement detection unit 1082 may create time-series data of the displacement of each observation point Pij by the following processing. That is, for example, the displacement detection unit 1082 displaces the observation point Pij based on the difference between the acoustic line signal frame data dsl and the acoustic line frame data ds (l-1) acquired in the previous transmission event. The amount of change ΔPtij of Ptij between transmission events is detected. Then, the displacement Ptij of the observation point Pij is generated by integrating the amount of change ΔPtij between the plurality of transmission events at the displacement Ptij for each observation point Pij. In this case, the ultrasonic diagnostic apparatus may not perform the step of transmitting / receiving the reference detection wave pulse and may not generate the reference acoustic line signal frame data ds0. Further, the detection of the change amount ΔPtij between the transmission events is not limited to between two consecutive transmission events, and the change amount ΔPtij of the displacement Ptij of the observation point Pij is calculated from the difference between any two acoustic line signal frame data dsl. It may be calculated.

The displacement detection unit 1082 generates the displacement amount frame data ptl by associating the time series data of the displacement with the observation point Pij and the transmission event.

(4) Arrival time detection unit 1083
The arrival time detection unit 1083 detects the arrival time of the wave surface of each observation point Pij based on the displacement frame data ptl. Specifically, as shown in FIG. 13C, the peak time tij of the displacement Dij of each observation point Pij is detected. As a method for detecting the peak time tij, a known method such as a TTP (Time to Peak) method or a correlation processing method can be used.

The arrival time detection unit 1083 associates the peak time tij with the observation point Pij to generate wave surface arrival time data ato.

(5) Propagation speed conversion unit 1084
The propagation velocity conversion unit 1084 calculates the propagation velocity of the shear wave in the region of interest. The propagation velocity conversion unit 1084 calculates the propagation velocity v of the shear wave between the adjacent observation points Pij. Specifically, as shown in FIGS. 13 (b) and 13 (d), the distance Rj (j + 1) between two adjacent observation points Pij and Pi (j + 1) is set for each of the observation points Pij and Pi (j + 1). The propagation velocity vj (j + 1) is calculated by dividing by the difference {ti (j + 1) -tij} between the peak times tij and ti (j + 1). The vertical axis d-axis in FIG. 13D is a distance axis indicating the traveling path of the shear wave. Next, the propagation velocity conversion unit 1084 calculates a representative value of the propagation velocity v of the shear wave as the propagation velocity of the shear wave in the region of interest. Representative values include, for example, an average value and a median value.

The propagation velocity conversion unit 1084 outputs the propagation velocity of the shear wave in the region of interest as the propagation velocity data vo.

(6) Mechanical property conversion unit 1085
The mechanical property conversion unit 1085 converts the propagation velocity of the shear wave in the region of interest into the mechanical property value of the subject. Examples of mechanical properties include shear modulus, Young's modulus, dynamic shear viscosity, and mechanical impedance.

For example, the shear modulus G can be calculated by the following formula using the subject density ρ and the propagation velocity v of the shear wave.
G = ρ ・ v ²
Further, for example, the Young's modulus E is assumed to be E = 2 (1 + ν) G using the Poisson ratio ν, assuming that the subject is an isotropic elastic body, and therefore ν = 0.5. , Can be calculated by the following formula.
E = 3ρ ・ v ²
Similarly, each of the dynamic shear viscosity and the mechanical impedance can be calculated by a known calculation using the propagation velocity v of the shear wave.

The mechanical characteristic conversion unit 1085 outputs the mechanical characteristic value in the region of interest as the mechanical characteristic data elf.

7. B mode image generator 110
The B-mode image generation unit 110 is a circuit that generates a B-mode tomographic image from a sequence of acoustic line signal frame data dsl.

The B-mode image generation unit 110 acquires one frame of acoustic line signal frame data dsl included in the sequence of acoustic line signal frame data dsl. Then, the B-mode image generation unit 110 performs envelope detection and logarithmic compression, converts the acoustic line signal frame data dsl into the luminance signal frame data bll, and outputs it to the display control unit 112.

8. Display control unit 112
The display control unit 112 is a circuit that generates a B-mode tomographic image or an image in which mechanical characteristic information is superimposed on the B-mode tomographic image and displays it on the display unit 114.

The display control unit 112 acquires the luminance signal frame data bll from the B mode image generation unit 110 and the mechanical characteristic data elf from the speed calculation unit 108, performs coordinate conversion, and performs a B mode image or a B mode. Generates an image in which mechanical characteristic data is superimposed on the image.

<Operation of ultrasonic diagnostic apparatus 100>
The operation of the integrated SWS sequence of the ultrasonic diagnostic apparatus 100 having the above configuration will be described.

1. 1. Outline of Operation FIG. 10 is a schematic view showing an outline of the process of the integrated SWS sequence in the ultrasonic diagnostic apparatus 100. The SWS sequence by the ultrasonic diagnostic apparatus 100 performs the step of setting the region of interest roi, transmitting and receiving the reference detection wave, and the reference acoustic line signal frame data ds0 for extracting the displacement due to the shear wave corresponding to each subsequent transmission event. Acquisition process, transmission of push wave pulse ppp to focus on specific site FP in the subject, transmission of shear wave excitation into the subject, transmission / reception of detection wave pwpl passing through the region of interest roi This consists of a step of transmitting and receiving a detection wave pulse pwpl that repeats a plurality of times, and a step of calculating the mechanical characteristics by measuring the shear wave propagation velocity and calculating the shear wave propagation velocity and the mechanical characteristics.

2. 2. Operation of SWS sequence when arithmetic circuit 160 can be used Below, shearing after a B-mode image in which a tissue is drawn based on a reflection component from the tissue of a subject based on a known method is displayed on the display unit 114. The operation of the wave velocity measurement process will be described.

The frame data of the B-mode image is a reflection component from the tissue of the subject based on the transmission and reception of ultrasonic waves performed by the transmission beam former unit 105 and the reception beam former unit 107 without transmitting the push wave pulse ppp. The frame data of the acoustic line signal is generated in time series based on the above, and after the acoustic line signal is processed by envelope detection, logarithmic compression, etc. and converted into a luminance signal, the luminance signal is coordinated to the orthogonal coordinate system. Convert and generate. The display control unit 112 causes the display unit 114 to display a B-mode image in which the tissue of the subject is drawn.

FIG. 11 is a flowchart showing the operation of SWSM processing in the ultrasonic diagnostic apparatus 100.

First, in step S10, the region of interest is set based on the operation input from the user. More specifically, the control unit 113 is designated by the operator from the operation input unit 102 in a state where the B mode image, which is a tomographic image of the subject acquired in real time by the probe 101, is displayed on the display unit 114. Using the obtained information as an input, the region of interest roi representing the analysis target range in the subject is set with reference to the position of the probe 101.

The operator specifies the area of interest roi, for example, displays the latest B-mode image recorded in the data storage unit 109 on the display unit 114, and sets the area of interest roi through an input unit (not shown) such as a touch panel or a mouse. It is done by specifying. Here, the region of interest roi is, for example, a fixed range away from the center in the column direction of the B-mode image.

Next, in step S20, the control unit 113 sets the push pulse transmission conditions. Specifically, the push wave generation unit 103 acquires information indicating the region of interest roi from the control unit 113, and sets the position of the transmission focal point FP of the push wave pulse ppp and the push wave transmission oscillator sequence Px. In this example, as shown in FIG. 3A, the push wave transmission oscillator train Px is a part of the plurality of oscillators 101a. Further, the column direction transmission focus position fx coincides with the column direction center position wc of the push wave transmission oscillator train Px, and the depth direction transmission focus position fz exists in the vicinity of the region of interest roi. However, the positional relationship between the region of interest roi and the transmission focus FP is not limited to the above, and may be appropriately changed depending on the shape of the site to be inspected of the subject and the like.

The information indicating the position of the transmission focus FP and the push wave transmission oscillator train Px is output to the transmission beam former unit 105 as a transmission control signal together with the pulse width PW of the push wave pulse ppp and the application start time PT.

Next, in step S30, the observation point candidate region Li is set in the region of interest roi. In this example, as shown in FIG. 8A, they are arranged at equal intervals as straight lines extending in the x direction. The observation point candidate region Li may be, for example, a straight line extending in the z direction through the center of any of the receiving oscillators Rpk.

Next, in step S40, the reference detection wave pulse is transmitted and received, and the acquired reference acoustic line signal frame data is saved. Specifically, a detection wave pulse is transmitted in the region of interest roi, and acoustic line signal frame data is generated for the reference point Rij on the observation point candidate region Li set in step S30 to generate reference acoustic line frame data. Is stored in the data storage unit 109.

Next, in step S50, a push pulse is transmitted. Specifically, the transmission beam former unit 105 has information indicating the position of the transmission focal point FP and the push wave transmission oscillator sequence Px acquired from the push wave generation unit 103, the pulse width PW of the push wave pulse ppp, and the application start time PT. A transmission profile is generated based on a transmission control signal consisting of. The transmission profile includes a pulse signal sp and a delay time tpk for each transmission oscillator included in the push wave transmission oscillator train Px. Then, the push wave pulse ppp is supplied to each transmission oscillator based on the transmission profile. Each transmitter transmits a pulsed push wave pp that focuses on a specific site in the subject.

Here, in the generation of the shear wave by the push wave pp, it will be described with reference to the schematic views of FIGS. 12A to 12C. 12 (a) to 12 (c) are spring models showing the mechanism of shear wave excitation by the push wave pp. In FIGS. 12 (a) to 12 (c), the elastic tissue in the subject is shown as a plurality of spheres connected by a spring, and each sphere corresponds to each position of the tissue in the subject. doing.

First, the push wave pp is applied to the focal point in the subject corresponding to the transmitting focal point F with the probe 101 in close contact with the skin surface. As a result, the sphere 603 corresponding to the focal point moves in the Z direction by the push pulse. Then, as shown in FIG. 12B, the sphere 604 connected to the sphere 603 is pulled in the Z direction, and the spheres 613 and 614 are pushed in the Z direction by the spheres 603 and 604, respectively. As a result, as shown in FIG. 12 (c), the balls 602 and 623 pushed directly by the push pulse move in the Z direction to push the other balls and become the balls 604. The sphere 614 pushed in the Z direction and pulled by the sphere 613 in the Z direction moves in the Z direction. By this operation, the vibration in the Z direction propagates to the positions of the spheres 604 and 614 that are not directly pressed by the push pulse. That is, when the focal portion is pressed in the Z direction, the focal portion vibrates in the Z direction, the tissue adjacent to the X direction is pulled in the Z direction, and the tissue also vibrates in the Z direction. Further, a chain motion occurs in which the tissue adjacent to the X direction is pulled in the Z direction and vibrates in the Z direction with respect to the tissue vibrating in the Z direction. Further, when such an operation occurs repeatedly, the vibration in the Z direction propagates in the X direction, that is, the shear wave propagates in the X direction.

The explanation will be continued by returning to FIG.

Next, in step S60, the detection wave pulse pwpl is transmitted / received a plurality of times to the region of interest roi, and the acquired sequence of the acoustic line signal frame data dsl is saved. Specifically, the transmission beam former unit 105 causes the oscillator included in the detection wave transmission oscillator train Tx to transmit the detection wave pulse pwpl toward the subject, and the reception beam former unit 107 causes the detection wave pulse reception vibration. The acoustic line signal frame data dsl is generated based on the reflected wave ec received by the oscillator included in the child train Rx. Immediately after the end of transmission of the push wave pp, for example, the above process is repeated 10,000 times per second. As a result, the acoustic line signal frame data dsl in the region of interest roi is repeatedly generated from immediately after the generation of the shear wave to the end of propagation. The generated sequence of the acoustic line signal frame data dsl is output to the data storage unit 109 and stored.

More specifically, the following processing is performed. First, the reception beam former unit 107 calculates the transmission time for the transmitted ultrasonic wave to reach the reference point Rij in the subject for any reference point Rij existing in the region of interest roi. Next, the receiving beam former unit 107 sets the detection wave pulse receiving vibrator train Rx, and the reflected detection wave from the reference point Rij is included in the detection wave pulse receiving vibrator train Rx, respectively. Calculate the reception time to reach. Then, the reception beam former unit 107 calculates the delay amount for each reference point Rij and each wave receiving oscillator Rwk from the transmission time and the reception time, and for each reference point Rij from the acoustic line signal frame data dsl. In addition, the received signal from the reference point Rij is identified. Next, the reception beam former unit 107 weights and adds the received signals identified for each reference point Rij, and calculates an acoustic line signal for the reference point Rij. Here, the weighting is, for example, reception apodization such that the weighting for the vibrator located at the center of the detection wave pulse receiving vibrator train Rx in the x direction is maximized. The reception beam former unit 107 stores the calculated acoustic line signal in the data storage unit 109.

Next, in step S70, the signal quality of the acoustic line signal frame data is extracted. Specifically, the parameter calculation unit 111 extracts the signal level of the acoustic line signal for each transmission event and for each reference point Rij. Then, a value indicating signal quality is calculated for each observation point candidate region Li. As the value indicating the signal quality, for example, the average value, the median value, or the minimum value of the signal levels can be used as the signal level. Alternatively, for example, as the noise level, the variance or standard deviation of the signal level, the sum of the absolute values of the differences from the average value, and the difference between the maximum value and the minimum value can be used. Alternatively, for example, the signal-to-noise ratio can be calculated from the signal level and the noise level. The parameter calculation unit 111 outputs the calculated parameter to the speed calculation unit 108.

Next, in step S80, the observation point Pij is set based on the signal quality. Specifically, the speed calculation unit 108 selects a plurality of observation point candidate regions Li based on the signal quality for each observation point candidate region Li received from the parameter calculation unit 111, and each of the selected observation point candidate regions Li. The observation point Pij used for measuring the propagation velocity of the shear wave is set in. As a method of selecting the observation point candidate region Li, for example, the observation point candidate region Li having a large signal level may be selected, or the observation point candidate region Li having a small noise level may be selected, for example. .. Alternatively, for example, the observation point candidate region Li having a signal level equal to or higher than a predetermined value and having a good signal-to-noise ratio may be extracted, or the observation point candidate region Li having a noise level equal to or lower than a predetermined value and having a good signal-to-noise ratio may be extracted. May be good. Further, the observation point candidate region Li having a signal-to-noise ratio equal to or higher than a predetermined reference and a large signal level may be extracted. Alternatively, for example, the observation point Pij may be set so that the distance of the observation point candidate region Li in the x direction is equal to or greater than a predetermined value and the signal quality is improved.

Next, in step S90, the displacement of each observation point Pij in the region of interest roi is detected for each transmission event, and the arrival time of the shear wave is specified. Specifically, in the first transmission event, the velocity calculation unit 108 performs correlation processing between the acoustic line signal frame data dsl and the reference acoustic line signal frame data ds0 for each observation point Pij, and performs correlation processing with the observation point Pij. The amount of position displacement for each is detected. Further, by performing this process for all the correlation events, the displacement amount for each transmission event is detected for each observation point Pij. Then, for each observation point Pij, the transmission event having the maximum displacement is specified, and the time when the transmission event is performed is specified as the peak time.

Next, in step S100, the propagation velocity of the shear wave is measured. Specifically, the speed calculation unit 108 uses the peak time for each observation point Pij specified in step S90 as an index, and divides the distance between two observation points Pij adjacent in the column direction by the time difference of the peak time. Calculate the propagation velocity of shear waves. In the embodiment, as shown in FIG. 13 (d), the observation point P ₁₁ arranged in the column direction, the observation point P _12, the observation point P _13, the propagation path of the vertical axis shear wave axis d, a peak on the horizontal axis Plot the time. Then, the propagation speed of the shear wave is calculated by calculating the slope between the observation points (= distance between the observation points ÷ time difference of the peak time). Then, a representative value of the propagation velocity of the shear wave is calculated and output as the propagation velocity of the shear wave in the region of interest roi. As the representative value, for example, the median value and the average value may be used. The velocity calculation unit 108 may further calculate the mechanical characteristic value of the subject in the region of interest roi based on the propagation velocity of the shear wave in the region of interest roi.

Finally, in step S110, the propagation velocity of the shear wave is superimposed and displayed on the B mode image. Specifically, for example, the information indicating the position of the region of interest roi, the propagation velocity of the shear wave, or the mechanical characteristic value is superimposed on the B mode image. In addition, only the information indicating the position of the region of interest roi may be superimposed on the B mode image, and the mechanical characteristic value may be displayed outside the B mode image.

As a result, the processing of the SWS sequence shown in FIG. 11 is completed. By the above shear wave velocity measurement process, the mechanical characteristic data elf by the SWS sequence can be calculated.

3. 3. Operation of SWS Sequence When the Calculation Circuit 160 is Not Used FIG. 14 is a flowchart showing a process of an integrated SWS sequence in the ultrasonic diagnostic apparatus 100 when the calculation circuit 160 is not used. Here, the same step numbers are assigned to the operations similar to those in FIG. 11, and detailed description thereof will be omitted. The SWS sequence by the ultrasonic diagnostic apparatus 100 performs the step of setting the region of interest roi, transmitting and receiving the reference detection wave, and the reference acoustic line signal frame data ds0 for extracting the displacement due to the shear wave corresponding to each subsequent transmission event. Acquisition process, transmission of push wave pulse ppp to focus on specific site FP in the subject, transmission of shear wave excitation into the subject, transmission / reception of detection wave pwpl passing through the region of interest roi This consists of a step of transmitting and receiving a detection wave pulse pwpl that repeats a plurality of times, and a step of calculating the mechanical characteristics by measuring the shear wave propagation velocity and calculating the shear wave propagation velocity and the mechanical characteristics. Hereinafter, the operation of the shear wave velocity measurement process after the B-mode image in which the tissue is drawn based on the reflection component from the tissue of the subject based on the known method is displayed on the display unit 114 will be described.

First, in step S10, the region of interest is set based on the operation input from the user.

Next, in step S20, the control unit 113 sets the push pulse transmission conditions.

Next, in step S120, the observation point Pij is set in the region of interest roi. In this example, for example, a predetermined number of them are arranged at equal intervals on a straight line extending in the x direction. Specifically, as shown in FIG. 15A, three observation points P11, P21, and P31 are set on a straight line HL extending in the x direction so that the interval is d. The number and intervals of observation points to be selected are not limited to the above cases. For example, four or more observation points may be provided in the region of interest roi, and as shown in FIG. 15B, the push wave pulse The closer to the transmission focal point FP, the wider the interval between the observation points Pij may be selected, but it is necessary that the number of observation points is at least 2, and a large number is more preferable.

Next, in step S40, the reference detection wave pulse is transmitted and received, and the acquired reference acoustic line signal frame data is saved. Specifically, a detection wave pulse is transmitted in the region of interest roi, acoustic line signal frame data is generated for the observation point Pij set in step S120, and stored in the data storage unit 109 as reference acoustic line frame data. To do.

Next, in step S50, a push pulse is transmitted.

Next, in step S60, the detection wave pulse pwpl is transmitted / received a plurality of times to the region of interest roi, and the acquired sequence of the acoustic line signal frame data dsl is saved. First, the reception beam former unit 107 calculates the transmission time for the transmitted ultrasonic waves to reach the observation candidate point Pij in the subject for any observation point Pij existing in the region of interest roi. Next, the receiving beam former unit 107 sets the detection wave pulse receiving vibrator train Rx, and the reflected detection wave from the observation point Pij is included in the detection wave pulse receiving vibrator train Rx, respectively. Calculate the reception time to reach. Then, the reception beam former unit 107 calculates the delay amount for each observation point Pij and for each wave receiving oscillator Rwk from the transmission time and the reception time, and for each observation point Pij from the acoustic line signal frame data dsl. In addition, the received signal from the observation point Pij is identified. Next, the reception beam former unit 107 weights and adds the received signals identified for each observation point Pij, and calculates an acoustic line signal for the observation point Pij. The reception beam former unit 107 stores the calculated acoustic line signal in the data storage unit 109.

Next, in step S90, the displacement of each observation point Pij in the region of interest roi is detected for each transmission event, and the arrival time of the shear wave is specified.

Next, in step S100, the propagation velocity of the shear wave is measured.

Finally, in step S110, the propagation velocity information of the shear wave is superimposed and displayed on the B mode image.

<Summary>
With the above configuration, when the arithmetic circuit 160 can be used, a wide range of observation point candidate regions Li is provided in the region of interest roi, and the observation point publication region Li capable of generating an acoustic line signal with good signal quality is provided. The observation point Pij is set, and the propagation velocity of the shear wave is measured based on the acoustic line signal corresponding to the observation point Pij. Therefore, the propagation velocity of the shear wave can be measured based on the high-quality acoustic line signal, and the accuracy of the propagation velocity of the measured shear wave can be improved. Further, since the number of observation points Pij can be limited to a number commensurate with the computing power of the speed calculation unit 108, it is possible to prevent a lack of computing power due to an excessive number of observation points Pij, resulting in a decrease in usability. Can be deterred.

On the other hand, when the arithmetic circuit 160 is not used, the observation point Pij is provided in the region of interest roi based on the preset rule, and the propagation velocity of the shear wave is measured based on the acoustic line signal corresponding to the observation point Pij. I do. Therefore, the processing can be performed based on the number of observation points Pij corresponding to the computing power of the speed calculation unit 108.

Therefore, in the ultrasonic diagnostic apparatus 100 according to the first embodiment, the propagation velocity measurement of the shear wave can be performed on a scale commensurate with the arithmetic ability regardless of whether the arithmetic circuit 160 can be used or not, and the arithmetic circuit 160 is used. If possible, the observation point Pij can be appropriately set without transmitting and receiving ultrasonic waves, and the accuracy of the measured shear wave propagation velocity can be improved.

<< Embodiment 2 >>
In the first embodiment, it is assumed that the arithmetic circuit assists the setting of the observation point Pij by determining the signal quality of the acoustic line signal. However, the information for assisting the setting of the observation point Pij is not limited to the quality of the acoustic line signal, and may be, for example, information indicating the mechanical characteristics of the subject.

In the second embodiment, the arithmetic circuit calculates the mechanical characteristics of the subject by a method different from that of the speed calculation unit, and the observation point Pij is set based on the mechanical characteristics.

<Ultrasonic diagnostic system 2000>
1. 1. Outline of the device An ultrasonic diagnostic system 2000 including the ultrasonic diagnostic device 200 according to the second embodiment will be described with reference to the drawings. FIG. 16 is a functional block diagram of the ultrasonic diagnostic system 2000 according to the second embodiment. The same functional blocks as those of the ultrasonic diagnostic system 1000 shown in FIG. 2 are designated by the same reference numerals, and detailed description thereof will be omitted. As shown in FIG. 16, in the ultrasonic diagnostic system 2000, a plurality of ultrasonic vibrators (transmuters) 101a that transmit ultrasonic waves toward a subject and receive the reflected waves are arranged in a row on the tip surface. An ultrasonic probe 101, an ultrasonic diagnostic apparatus 200 that causes the probe 101 to transmit and receive ultrasonic waves and generate an ultrasonic signal based on an output signal from the probe 101, an operation input unit 102 that receives an operation input from an inspector, and an ultrasonic image. Has a display unit 114 for displaying on the screen. The probe 101, the operation input unit 102, and the display unit 114 are each configured to be connectable to the ultrasonic diagnostic apparatus 200.

<Outline of configuration of ultrasonic diagnostic apparatus 200>
Next, the ultrasonic diagnostic apparatus 200 according to the second embodiment will be described.

The ultrasonic diagnostic apparatus 200 includes a push wave generation unit 103, a detection wave generation unit 104, a transmission beam former unit 105, a multiplexer unit 106, a reception beam former unit 107, a speed calculation unit 208, a data storage unit 109, and a B-mode image generation unit. It includes 110, a map type speed calculation unit 261 and a parameter calculation unit 262, a display control unit 212, and a control unit 213.

Of these, the multiplexer section 106, transmission beam former section 105, reception beam former section 107, push wave generation section 103, detection wave generation section 104, speed calculation section 208, and control section 213 constitute an ultrasonic signal processing circuit 250. .. Further, the map type speed calculation unit 261 and the parameter calculation unit 262 constitute an arithmetic circuit 260.

Each element constituting the ultrasonic signal processing circuit 250 is realized by a hardware circuit such as FPGA or ASIC, respectively. Alternatively, the configuration may be realized by a processor such as a CPU or GPU and software, and a configuration using a GPU is particularly called GPGPU. These components can be a single circuit component, or can be an aggregate of a plurality of circuit components. Further, a plurality of components can be combined into one circuit component, or an aggregate of a plurality of circuit components can be formed. Further, the arithmetic circuit 260 is composed of, for example, a GPGPU, and is realized by a GPU, a memory, a power supply, and software that operates the GPU.

<Structure of each part of ultrasonic diagnostic apparatus 200>
Next, the configuration of each block included in the ultrasonic diagnostic apparatus 200 will be described.

1. 1. Control unit 213
Generally, in a state where a B-mode image, which is a tomographic image of a subject acquired by the probe 101 in real time, is displayed on the display unit 114, the operator uses the B-mode image displayed on the display unit 114 as an index. , The analysis target position in the subject is specified and input to the operation input unit 102. The control unit 113 sets the area of interest roi, which is the analysis target range, by inputting the information specified by the operator from the operation input unit 102. Here, since the mechanical property of the subject acquires one value for the entire area of interest roi, it is preferable that the area of interest roi is in a narrow range so that the mechanical property does not change significantly inside the area roi. Alternatively, the control unit 113 may set the region of interest roi based on the position of the oscillator train (101a) composed of the plurality of oscillators 101a on the probe 101. For example, the region of interest roi may be set in the front direction of the oscillator 101a slightly away from the center of the oscillator train (101a) composed of the plurality of oscillators 101a.

Further, the control unit 213 sets the analysis target area roi2 including the area of interest roi and which is the target of the map type speed calculation. Here, in the analysis target region roi2, in order to acquire the propagation state of the wave surface of the shear wave and the distribution tendency of the mechanical characteristics, it is preferable that the mechanical characteristics are in a wide range so as not to be uniform inside. Alternatively, the control unit 213 may set the analysis target region roi2 based on the position of the oscillator train (101a) composed of the plurality of oscillators 101a on the probe 101. For example, the analysis target region roi2 may be the entire area of the ultrasonic irradiation region Ax.

Further, the control unit 213 controls other blocks of the ultrasonic diagnostic apparatus 200, which will be described later, based on a command from the operation input unit 102. Further, the control unit 213 determines whether or not the arithmetic circuit 260 can be used, and changes the control contents of other blocks according to the determination result.

2. 2. Map type speed calculation unit 261
The map-type velocity calculation unit 261 detects the displacement of the structure in the analysis target area roi2 from the sequence of the acoustic line signal frame data dsl for the plurality of second observation points Qrs in the analysis target area roi2, and detects the displacement of the structure in the analysis target area roi2, and the velocity of the shear wave. It is a circuit to calculate. The second observation points QRs are arranged in a mesh shape in the analysis target region roi2 so as to be evenly spaced in the x direction and evenly spaced in the z direction. Note that r is a value indicating the order in the x direction, and s is a value indicating the order in the z direction.

FIG. 17 is a functional block diagram showing the configuration of the map type speed calculation unit 261. The map-type velocity calculation unit 261 includes a displacement detection unit 2611, a wave surface detection unit 2612, a wave surface arrival time detection unit 2613, a propagation speed conversion unit 2614, and a mechanical characteristic conversion unit 2615.

(1) Displacement detection unit 2611
The displacement detection unit 2611 sets the acoustic line signal frame data dsl of one frame included in the sequence of the acoustic line signal frame data dsl and the reference acoustic line signal frame for each of the second observation points Qrs in the analysis target region roi2. Data (reference acoustic line signal frame data) ds0 and is acquired. The displacement detection unit 2611 detects the displacement of each of the second observation points Qrs from the difference between the acoustic line signal frame data dsl and the reference acoustic line signal frame data ds0. Then, the displacement detection unit 2611 repeats this process to create time-series data of the displacement of each of the second observation points Qrs.

The displacement detection unit 2611 associates the displacement time series data with the second observation point Qrs and the transmission event to generate the displacement amount frame data ptl.

(2) Wave surface detection unit 2612
The wave surface detection unit 2612 detects the position of the wave surface for each transmission event based on the displacement amount frame data ptl. The wave surface is detected by, for example, the procedure of extracting the displacement region, thinning the line, spatial filtering, and time filtering. The displacement region is extracted, for example, by using a dynamic threshold value to extract a region having a large displacement. In the thinning process, for example, the displacement region is converted into a wave surface by using Hilditch's thinning algorithm or the like. In spatial filtering, for example, a wave surface that is less than a predetermined length is erased. Time filtering is performed, for example, by comparing the positions and shapes of wave surfaces for two consecutive transmission events, and erroneous for wave surfaces that cannot be associated, wave surfaces with extremely high or extremely slow wave velocity. Performs erasing processing as detection.

The wave surface detection unit 2612 generates time series data of the wave surface as wave surface frame data wfl.

(3) Wave surface arrival time detection unit 2613
The wave surface arrival time detection unit 2613 detects the arrival time of the wave surface in the analysis target region roi2 based on the wave surface frame data wfl. The arrival time of the wave surface is performed by associating the position of the wave surface with the transmission event time based on the wave surface frame data wfl. The wave surface arrival time detection unit 2613 outputs wave surface arrival time data ato indicating the wave surface arrival time for each position in the analysis target area roi2.

(4) Propagation speed conversion unit 2614
The propagation velocity conversion unit 2614 detects the moving velocity of the shear wave in the analysis target region roi2 based on the wave surface arrival time data ato. The moving speed of the shear wave is calculated by dividing the distance of each position in the analysis target region roi2 by the wave surface arrival time difference based on the time-series change of the wave surface position.

The propagation velocity conversion unit 2614 outputs the propagation velocity of the shear wave at each position in the analysis target region roi2 as the propagation velocity data vo.

(5) Mechanical property conversion unit 2615
The mechanical property conversion unit 2615 converts the propagation velocity of the shear wave at each position in the analysis target region roi2 into the mechanical property value of the position of the subject. Examples of mechanical properties include shear modulus, Young's modulus, dynamic shear viscosity, and mechanical impedance.

The mechanical characteristic conversion unit 2615 outputs the mechanical characteristics at each position in the analysis target region roi2 as two-dimensional mechanical characteristic data elf2d.

3. 3. Parameter calculation unit 262
The parameter calculation unit 262 is a circuit that generates parameters for setting a plurality of observation points Pij in the region of interest roi based on the two-dimensional mechanical characteristic data elf2d. The parameter calculation unit 262 outputs one of the shear modulus, Young's modulus, dynamic shear viscosity, and mechanical impedance as a parameter for at least one of the second observation points Qrs existing in the region of interest roi. .. Alternatively, for example, the parameter calculation unit 262 may output the arrival time of the shear wave as a parameter for the second observation point Qrs that exists at least in the region of interest roi, and the arrival time of the shear wave may be output. A map with the same arrival time, which is connected by a curve with the same positions as simultaneous arrival lines, or a propagation direction map showing the traveling direction of the shear wave may be used as parameters. The parameters are not limited to those described above, and may be, for example, the reliability of mechanical characteristic values, the estimated position of the structure, and the like. Further, the parameter calculation unit 262 may output a mechanical characteristic value or the like for the second observation point QRs existing outside the region of interest roi as a parameter.

4. Speed calculation unit 208
The velocity calculation unit 208 sets a plurality of observation points Pij in the region of interest roi based on the parameters output from the parameter calculation unit 262, and is interested in the set observation points Pij from the sequence of the acoustic line signal frame data dsl. It is a circuit that detects the displacement of the structure in the region roi and calculates the velocity of the shear wave.

FIG. 18 is a functional block diagram showing the configuration of the speed calculation unit 208. The speed calculation unit 208 includes an observation point setting unit 2081, a displacement detection unit 1082, an arrival time detection unit 1083, a propagation speed conversion unit 1084, and a mechanical characteristic conversion unit 1085. Since the configurations other than the observation point setting unit 2081 are the same as the speed calculation unit 108 according to the first embodiment, only the observation point setting unit 2081 having a configuration different from that of the first embodiment will be described below.

(1) Observation point setting unit 2081
The observation point setting unit 2081 sets the first observation point Pij based on the parameters. More specifically, the observation point setting unit 2081 selects the first observation point Pij from the second observation point Qrs existing in the region of interest roi based on the parameters. As a selection criterion, for example, when the parameter is shear modulus, the second observation point Qrs in which the ratio of the shear wave modulus to the average value of the shear modulus in the region of interest roi is within a predetermined range is selected. .. Alternatively, for example, the second observation point Qrs is selected so that the larger the value of the shear modulus, the wider the interval between the first observation points Pij, depending on the value of the shear modulus. Alternatively, for example, when the parameter is the shear wave arrival time for each position, the first observation point Pij may be provided so as to be orthogonal to the simultaneous arrival line, that is, to be aligned in the traveling direction of the shear wave.

5. Display control unit 212
The display control unit 212 is a circuit that generates a B-mode tomographic image or an image in which mechanical characteristic information is superimposed on the B-mode tomographic image and displays it on the display unit 114.

The display control unit 212 acquires the luminance signal frame data bll from the B mode image generation unit 110 and the mechanical characteristic data elf from the speed calculation unit 208, performs coordinate conversion, and performs a B mode image or a B mode. Generates an image in which mechanical characteristic data is superimposed on the image. The display control unit 212 further acquires the two-dimensional mechanical characteristic data elf2d, performs coordinate conversion, and superimposes it as a color map on the B mode image, or superimposes the simultaneous arrival line on the B mode image. May be good.

<Operation of ultrasonic diagnostic apparatus 200>
The operation of the integrated SWS sequence of the ultrasonic diagnostic apparatus 200 having the above configuration will be described. Since the operation of the SWS sequence when the arithmetic circuit 260 is not used is the same as that of the first embodiment, the description thereof will be omitted, and only the operation of the SWS sequence when the arithmetic circuit 260 can be used will be described. It should be noted that the matters overlapping with the first embodiment will be described to that effect and detailed description thereof will be omitted.

Hereinafter, the operation of the shear wave velocity measurement process after the B-mode image in which the tissue is drawn based on the reflection component from the tissue of the subject based on the known method is displayed on the display unit 114 will be described. FIG. 19 is a flowchart showing the operation of SWSM processing in the ultrasonic diagnostic apparatus 200.

First, in step S210, the region of interest roi and the analysis target region roi2 are set based on the operation input from the user. The setting of the region of interest roi is the same as in step S10. The control unit 213 sets the analysis target region roi2, which is the target of the map-type shear wave propagation analysis, based on the position of the probe 101 based on the position of the region of interest roi.

Next, in step S220, the control unit 213 sets the push pulse transmission condition. Specifically, the push wave generation unit 103 acquires information indicating the region of interest roi and the analysis target region roi2 from the control unit 213, and sets the position of the transmission focus FP of the push wave pulse ppp and the push wave transmission oscillator sequence Px. To do. The information indicating the position of the transmission focus FP and the push wave transmission oscillator train Px is output to the transmission beam former unit 105 as a transmission control signal together with the pulse width PW of the push wave pulse ppp and the application start time PT.

Next, in step S230, the second observation point QRs is set in the analysis target region roi2. In this example, they are arranged in a mesh shape so as to be evenly spaced in the x direction and evenly spaced in the z direction. It is preferable that the second observation point Qrs exists on a straight line extending in the z direction through the center of any of the receiving oscillators Rpk.

Next, in step S240, the reference detection wave pulse is transmitted and received, and the acquired reference acoustic line signal frame data is saved. Specifically, the detection wave pulse is transmitted in the analysis target region roi2, the acoustic line signal frame data is generated for the second observation point QRs set in step S230, and the data storage unit is used as the reference acoustic line frame data. Save to 109.

Next, in step S250, a push pulse is transmitted. The details are the same as in step S50 and will be omitted.

Next, in step S260, the detection wave pulse pwpl is transmitted / received a plurality of times to the analysis target region roi2, and the acquired sequence of the acoustic line signal frame data dsl is saved. The details are the same as in step S60 except that the sound line signal is generated at the second observation point QRs, and thus the details will be omitted. The generated sequence of the acoustic line signal frame data dsl is output to the data storage unit 109 and stored.

Next, in step S300, propagation analysis of the shear wave in the analysis target region roi2 is performed.

FIG. 20 is a flowchart showing the details of the map type shear wave propagation analysis. FIG. 21 is a schematic diagram showing the operation of displacement detection and shear wave propagation analysis.

First, in step S310, the reference acoustic line signal frame data ds0 stored in the data storage unit 109 and each acoustic line signal frame data dsl are obtained from the difference between the reference acoustic line signal frame data ds0 and the acoustic line signal frame data. The displacement is detected at the time when dsl is acquired. Column A in FIG. 21 shows reference acoustic line signal frame data ds0 and acoustic line signal frame data dsl generated in each transmission event, and column B shows the displacement amount frame calculated for each transmission event in step S150. The data ptl is shown.

Next, in step S320, the wave surface is detected. Specifically, the wave surface is detected by, for example, a procedure of extraction of a displacement region, thinning process, spatial filtering, and time filtering. The displacement region is extracted, for example, by using a dynamic threshold value to extract a region having a large displacement. In the thinning process, for example, the displacement region is converted into a wave surface by using Hilditch's thinning algorithm or the like. In spatial filtering, for example, a wave surface that is less than a predetermined length is erased. Time filtering is performed, for example, by comparing the positions and shapes of wave surfaces for two consecutive transmission events, and erroneous for wave surfaces that cannot be associated, wave surfaces with extremely high or extremely slow wave velocity. Performs erasing processing as detection.

Next, in step S330, the position of the wave surface for each detected wave transmission is detected by associating the wave surfaces. Specifically, the position of the wave surface at each time is detected based on the result of the time filtering process in step S320.

Next, in step S340, the velocity of the shear wave is estimated by assuming that the associated wave surfaces are the same wave surface and dividing the distance between the two observation points by the difference in the wave surface arrival time. Column D in FIG. 21 shows a state in which the velocity of the shear wave is associated with the coordinates ij of the observation point. The map-type velocity calculation unit 261 stores the propagation velocity data vf generated by associating the velocity of the shear wave with the coordinates ij of the observation point in the data storage unit 109.

Next, in step S350, the propagation velocity of the shear wave is converted into a mechanical characteristic value.

Next, in step S360, parameters for setting a plurality of observation points Pij in the region of interest roi are generated based on the two-dimensional mechanical characteristic data elf2d. The parameter calculation unit 262 outputs any one of the shear modulus, Young's modulus, dynamic shear viscosity, and mechanical impedance as a parameter for the second observation point Qrs existing in the region of interest roi. Alternatively, for example, the parameter calculation unit 262 may output the arrival time of the shear wave as a parameter for the second observation point Qrs existing in the region of interest roi, and the arrival time of the shear wave is the same. A map with the same arrival time and a map showing the traveling direction of the shear wave, which is connected by a curve with the positions as simultaneous arrival lines, may be used as parameters. The parameters are not limited to those described above, and may be, for example, the reliability of mechanical characteristic values, the estimated position of the structure, and the like.

The explanation will be continued by returning to FIG. Next, in step S410, the observation point Pij is set in the region of interest roi based on the shear wave propagation analysis result in the analysis target region roi2. Specifically, the velocity calculation unit 208 uses the observation point Pij used for propagation analysis of the shear wave from the second observation point Qrs based on the mechanical characteristic value for each second observation point Qrs received from the parameter calculation unit 262. Is extracted. As a method of extraction, for example, extraction may be performed so that the difference in mechanical characteristic values between the first observation points Pij becomes smaller, or for example, as the Young's modulus increases, the interval between the first observation points Pij becomes smaller. It may be extracted so as to spread. Alternatively, for example, the direction in which the first observation points Pij are lined up coincides with the propagation direction of the shear wave, that is, the direction in which the first observation points Pij are lined up is orthogonal to the direction in which the arrival times of the shear waves are the same. It may be extracted.

Next, in step S420, the displacement of each observation point Pij in the region of interest roi is detected for each transmission event, and the arrival time of the shear wave is specified. The details are the same as in step S90 and will be omitted.

Next, in step S430, the propagation velocity of the shear wave is measured. The details are the same as in step S100 and will be omitted.

Finally, in step S440, the propagation information of the shear wave is superimposed and displayed on the B mode image. Specifically, for example, the information indicating the position of the region of interest roi and the mechanical characteristic value are superimposed on the B mode image. In addition, only the information indicating the position of the region of interest roi may be superimposed on the B mode image, and the mechanical characteristic value may be displayed outside the B mode image. Furthermore, the results of the map-type shear wave propagation analysis may be superimposed in the form of a color map, a shear wave simultaneous arrival timeline, a shear wave propagation direction map, or the like.

As a result, the processing of the SWS sequence shown in FIG. 19 is completed. By the above shear wave velocity measurement process, the mechanical characteristic data elf by the SWS sequence can be calculated.

<Summary>
With the above configuration, when the arithmetic circuit 260 can be used, map-type shear wave propagation analysis that requires a large-scale arithmetic resource is performed, the observation point Pij is set based on the result, and the observation point Pij is set. Shear wave propagation velocity is measured based on the corresponding acoustic line signal. Therefore, the position of the observation point Pij in the measurement of the propagation velocity of the shear wave can be optimized, and the accuracy of the measured propagation velocity of the shear wave can be improved. Further, since the number of observation points Pij can be limited to a number commensurate with the computing power of the speed calculation unit 208, it is possible to suppress a lack of computing power and thereby suppress a deterioration in usability.

On the other hand, when the arithmetic circuit 260 is not used, the observation point Pij is provided in the region of interest roi based on the preset rule, and the propagation velocity of the shear wave is measured based on the acoustic line signal corresponding to the observation point Pij. I do. Therefore, the processing can be performed based on the number of observation points Pij corresponding to the computing power of the speed calculation unit 208.

Therefore, in the ultrasonic diagnostic apparatus 100 according to the second embodiment, the propagation velocity measurement of the shear wave can be performed on a scale commensurate with the arithmetic ability regardless of whether the arithmetic circuit 160 can be used or not, and the arithmetic circuit 160 is used. If possible, map-type shear wave propagation analysis can be performed without transmitting and receiving ultrasonic waves separately, and measurement conditions should be optimized in measuring the shear wave propagation velocity in the region of interest based on the results. Therefore, the accuracy of shear wave propagation measurement can be improved.

<< Embodiment 3 >>
In the first and second embodiments, the case where the configuration of the ultrasonic diagnostic apparatus does not change depending on whether or not the arithmetic circuits 160 and 260 are used has been described. However, the arithmetic circuit 160 or 260 may be detachably configured and the ultrasonic diagnostic apparatus may be used only when the arithmetic circuit is mounted.

FIG. 22A is an external view showing the ultrasonic diagnostic system 3000 according to the third embodiment. As shown in FIG. 22A, the ultrasonic diagnostic system 3000 has a portable main body unit (HCU; Hand Carry Unit) 300, a probe 301, a cart 303, an extension unit 304, and an input unit 305. The display unit 302 is built in the portable main body unit 300.

The portable main body 300 is an ultrasonic diagnostic apparatus that causes the probe 301 to transmit and receive ultrasonic waves, generates an ultrasonic image based on an output signal from the probe 301, and displays the ultrasonic image on the display unit 302. The ultrasonic diagnostic apparatus 100 Of these, the arithmetic circuit 160, that is, the entire configuration except for the parameter calculation unit 111. The portable main body unit 300 is realized by, for example, a switch fabric compatible with PCI Express × 16, a personal computer connected to the switch fabric, and a transmission / reception unit connected to the switch fabric and composed of an FPGA. The personal computer includes at least a control unit 113 and a speed calculation unit 108, and includes at least a CPU, a memory, a power supply unit, and software for controlling them. The personal computer preferably includes a GPU. The GPU may be provided with a dedicated memory and mounted separately from the CPU, or the CPU and the GPU may be configured by one chip and share the memory. The transmission / reception unit includes at least a transmission beam former unit 105, a reception beam former unit 107, and a multiplexer unit 106. The communication specifications of the switch fabric are not limited to PCI Express × 16, and any bus can be used as long as it has a sufficient speed (bandwidth) for communication between the transmission / reception unit and the personal computer, and between the personal computer and the extension unit 304 described later. May be used.

The cart 303 is a stand that can be moved with the portable main body unit 300 mounted on it, and includes a top plate 321, an extension unit 304, and an input unit 305.

The extension unit 304 includes an arithmetic circuit 160. Specifically, it is composed of a GPU, a memory, a power supply unit for operating these, and the like. The software for controlling the GPU may be possessed by the extension unit 304, but may be included in the software of the personal computer of the portable main unit 300, and the latter configuration simplifies the control. The specific configuration is not limited to the GPU, and may be a processor, a module including the processor and an arithmetic circuit.

The input unit 305 is, for example, a keyboard that can be connected to the portable main body unit 300.

When the portable main body 300 is removed from the cart 303, the portable main body 300 performs an operation without using the arithmetic circuit 160 as shown in the flowchart of FIG. On the other hand, when the portable main body 300 is attached to the cart 303, the portable main body 300 performs an operation using the arithmetic circuit 160 as shown in the flowchart of FIG.

<Detachable configuration>
The back surface of the portable main body 300 is provided with a removable portion. The detachable portion includes, for example, two engaging grooves 311 extending in the X direction, as shown in FIG. 22 (b). The engaging groove 311 is an L-shaped groove, and a locking claw 312 is provided on the back side of the portable main body 300. The locking claw 312 is urged into the locking groove by a spring, and the back side of the portable main body 300 has an inclined surface. Therefore, the engaging convex portion 322, which will be described later, is allowed to be inserted into the engaging groove 311, but the engaging convex portion 322 inserted deep into the engaging groove 311 is prevented from being pulled out. On the back surface of the portable main body 300, a release button 313 for pulling up the locking claw 312 from the locking groove and a connector 314 are provided. The connector 314 stores a signal line extending from the switch fabric. It is preferable that the connector 314 is compatible with so-called hot-swap. Further, the connector 314 may include a signal line that receives an input from the input unit 305.

On the other hand, the top plate 321 of the cart 303 is provided with a detachable portion. As shown in FIG. 22 (c), the detachable portion is provided with two engaging convex portions 322 extending in the X direction and a connector 323, for example. The engaging protrusion 322 is an L-shaped protrusion that can engage with the engaging groove 311. As shown in FIG. 22 (c), the closer the engaging convex portion 322 is to the front side of the cart 303, the smaller the portion extending in the Y direction, or the higher the engaging convex portion 322 in the Z direction in a state where there is no portion extending in the Y direction. It may be low. With such a shape, the portable main body portion 300 can move relative to the top plate 321 in the Z direction in a state where only a part of the engaging convex portion 322 is inserted into the engaging groove 311. , The portable main body 300 can be easily attached and detached. The connector 323 is in a state in which the engaging convex portion 322 of the top plate 321 and the engaging groove 311 of the portable main body 300 are engaged with each other, and the portable main body 300 cannot move relative to the top plate 321 due to the locking claw 312. It is provided so as to engage with the connector 314. The connector 323 stores a signal line extending from the arithmetic circuit 160 of the extension unit 304. Further, the connector 323 may include a signal line from the input unit 305.

When attaching the portable main body 300 to the cart 303, align the front end of the engaging convex portion 322 with the engaging groove 311 and place the portable main body 300 on the rear side of the cart in the X direction. Slide it. As a result, the engaging groove 311 serves as a guide, and the engaging convex portion 322 and the engaging groove 311 engage with each other. When the engaging convex portion 322 is completely retracted in the engaging groove 311, the connector 314 and the connector 323 are engaged, and the portable main body portion 300 and the extension portion 304 are electrically connected. Further, the locking claw 312 protrudes into the engaging groove 311 to prevent the portable main body 300 from moving relative to the cart 303. As a result, the portable main body 300 is fixed to the cart 303.

On the other hand, when removing the portable main body 300 from the cart 303, the portable main body 300 is slid to the front side of the cart 303 while pressing the release button 313, and the portable main body 300 is further moved to the front side of the cart 303. Pull out to. By pressing the release button 313, the engaging convex portion 322 and the engaging groove 311 can be relatively moved in the X direction, and by sliding the portable main body portion 300 toward the front side of the cart 303, the connector 314 and the connector 323 are connected. Is released. Further, by sliding the portable main body portion 300 toward the front surface side of the cart 303, the engagement between the engaging convex portion 322 and the engaging groove 311 is completely disengaged.

<Functional configuration>
The control unit of the portable main unit 300 determines whether or not the portable main unit 300 is fixed to the cart 303, and if it is not fixed, determines that the arithmetic circuit 160 is not used and is fixed. In that case, it is decided to use the arithmetic circuit 160. As a method of determining whether or not the portable main body 300 is fixed to the cart 303, for example, there is a method of detecting whether or not the connection between the switch fabric and the arithmetic circuit 160 is valid. The determination method is not limited to this case, and for example, the control unit may try to communicate with the arithmetic circuit 160 and determine whether or not it succeeds. Alternatively, the connector 314 may be provided with a detection signal line for detecting whether or not it is connected to the connector 323, and the determination may be made based on the state of the detection signal line. Alternatively, a sensor for detecting whether or not the portable main body 300 is fixed to the cart 303 may be provided on the back surface or the back surface of the connector 314, the engaging groove 311 or the portable main body 300.

<Summary>
According to the ultrasonic diagnostic apparatus according to the third embodiment, when operating only in the portable main body, the observation point Pij is provided in the region of interest roi based on the set rule, and the sound corresponding to the observation point Pij is provided. Shear wave propagation velocity is measured based on the line signal. Therefore, it is not necessary for the portable main body to have high computing power. In addition, since power saving is possible due to the small amount of calculation, the portable main body can be miniaturized by designing the exhaust heat of the portable main body and simplifying the circuit, and the operating time can be extended by the built-in storage battery. It will be easy. On the other hand, when the portable main body is mounted on the cart, the position of the observation point Pij is optimized based on the parameters by the parameter calculation unit. Therefore, it is possible to optimize the position of the observation point Pij after using the computing power of the computing circuit only for calculating the parameters, and it is possible to improve the accuracy of the measured shear wave propagation velocity. Therefore, although SWSM can be executed only by the portable main body, its accuracy can be further improved when it is integrated with the cart.

<< Other modifications according to the embodiment >>
(1) In each embodiment, it is assumed that the reception beam former unit 107 generates an acoustic line signal for the observation candidate point Qij or the second observation point QRs, but for example, when the arithmetic circuit 160 or 260 can be used. , The arithmetic circuit 160 or 260 may generate an acoustic line signal for the observation candidate point Qij or the second observation point Qrs. At this time, the reception beam former unit 107 may not generate an acoustic line signal, and the velocity calculation unit 108 or 208 may receive an acoustic line signal related to the observation point Pij selected from the arithmetic circuit 160 or 260.

(2) In each embodiment, the B-mode image generation unit 110 generates a B-mode image. However, for example, when the arithmetic circuit 160 or 260 can be used, the arithmetic circuit 160 or 260 causes the B-mode image. May be generated. With this configuration, in particular, when the speed calculation unit 108 or 208 and the B-mode image generation unit 110 are realized on the memory with the same CPU or GPU, or when the memory is shared. The computing power of the speed calculation unit 108 or 208 can be improved.

(3) In the first embodiment, the observation point Pij is determined based on the signal quality of the acoustic line signal and in the second embodiment based on the result of the map-type shear wave propagation analysis. For example, these are combined to determine the acoustic line. The observation point Pij may be determined based on both the signal quality of the signal and the result of the map-type shear wave propagation analysis.

(4) In the second embodiment, the focus of the push pulse is set to one for the map-type shear wave propagation analysis. For example, a plurality of focal points having the same x-coordinate but different z-coordinates are provided, and the z-coordinates are arranged in ascending order. Alternatively, push pulses may be sequentially transmitted in descending order of the z-coordinate to control the shear wave to become a virtual plane wave.

(5) The ultrasonic diagnostic apparatus according to each embodiment may realize all or a part of its components by an integrated circuit of one chip or a plurality of chips, or may be realized by a computer program. However, it may be carried out in any other form. For example, the push wave generation unit and the detection wave generation unit may be realized by one chip, the reception beam former unit may be realized by one chip, and the speed detection unit or the like may be realized by another chip.

When it is realized by an integrated circuit, it is typically realized as an LSI (Large Scale Integration). Although it is referred to as LSI here, it may be referred to as IC, system LSI, super LSI, or ultra LSI depending on the degree of integration.

Further, the method of making an integrated circuit is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. An FPGA (Field Programmable Gate Array) that can be programmed after the LSI is manufactured, or a reconfigurable processor that can reconfigure the connection and settings of circuit cells inside the LSI may be used.

Furthermore, if an integrated circuit technology that replaces an LSI appears due to advances in semiconductor technology or another technology derived from it, it is natural that the functional blocks may be integrated using that technology.

Further, the ultrasonic diagnostic apparatus according to each embodiment and each modification may be realized by a program written in a storage medium and a computer that reads and executes the program. The storage medium may be any recording medium such as a memory card or a CD-ROM. Further, the ultrasonic diagnostic apparatus according to the present invention may be realized by a program downloaded via a network and a computer that downloads and executes the program from the network.

(7) The embodiments described above all show a preferable specific example of the present invention. Numerical values, shapes, materials, components, arrangement positions and connection forms of components, processes, order of processes, etc. shown in the embodiments are examples, and are not intended to limit the present invention. Further, among the components in the embodiment, the steps not described in the independent claims showing the highest level concept of the present invention will be described as arbitrary components constituting the more preferable form.

Further, for the sake of easy understanding of the invention, the scale of the component of each figure given in each of the above embodiments may be different from the actual scale. Further, the present invention is not limited to the description of each of the above-described embodiments, and can be appropriately modified without departing from the gist of the present invention.

Further, in the ultrasonic diagnostic apparatus, there are members such as circuit parts and lead wires on the substrate, but various aspects of electrical wiring and electric circuits can be implemented based on ordinary knowledge in the technical field. Since the description of the present invention is not directly related, the description is omitted. It should be noted that each of the figures shown above is a schematic diagram and is not necessarily exactly illustrated.

≪Summary≫
(1) The ultrasonic diagnostic apparatus according to the embodiment includes an ultrasonic signal processing circuit and an arithmetic circuit configured to be detachable from the ultrasonic signal processing circuit, and the ultrasonic signal processing circuit is A push wave transmitter that transmits a push wave for generating displacement in the subject to the ultrasonic probe, and a detection wave that passes through the region of interest including the analysis target position in the subject following the transmission of the push wave. Is received from the ultrasonic probe, and the received signal based on the ultrasonic wave reflected from the region of interest corresponding to the detected wave is received from the ultrasonic probe, and based on the received signal, the said A detection wave receiver that generates an ultrasonic signal by performing phasing addition for a plurality of positions in the region of interest, and a plurality of analysis target signals selected from the plurality of the acoustic line signals, based on the selected analysis target signal. , The calculation circuit includes a mechanical characteristic calculation unit for calculating the mechanical characteristics of the analysis target position, and the calculation circuit calculates a parameter for selecting the analysis target signal based on the plurality of the acoustic line signals. When the arithmetic circuit is mounted on the ultrasonic signal processing circuit, the mechanical characteristic calculation unit selects a plurality of the analysis target signals based on the parameters.

Further, the control method of the ultrasonic diagnostic apparatus according to the embodiment is a control method of the ultrasonic diagnostic apparatus including an arithmetic circuit configured to be removable, and a push wave for generating a displacement in the subject is generated. The ultrasonic probe is transmitted, and following the transmission of the push wave, the detection wave passing through the region of interest including the analysis target position in the subject is transmitted to the ultrasonic probe, and the interest corresponds to the detected wave. A received signal based on the ultrasonic wave reflected from the region is received from the ultrasonic probe, and based on the received signal, phasing addition is performed for a plurality of positions in the region of interest to generate an acoustic line signal, and a plurality of acoustic line signals are generated. A plurality of analysis target signals are selected from the acoustic line signals, and a plurality of analysis target signals are selected from the plurality of acoustic line signals, including a process of calculating the mechanical characteristics of the analysis target position based on the selected analysis target signals. The analysis target includes a process of calculating the mechanical characteristics of the analysis target position based on the selected and selected analysis target signal, and when the arithmetic circuit is mounted, the analysis target is based on a plurality of the acoustic line signals. In the process of further including a process of causing the arithmetic circuit to calculate a parameter for selecting a signal and selecting a plurality of analysis target signals from a plurality of the acoustic line signals, a plurality of the analysis target signals based on the parameter. It is characterized by selecting.

According to the present disclosure, when the arithmetic circuit is connected to the ultrasonic signal processing circuit by the above configuration or method, the acoustic line signal is selected based on the parameters generated by the parameter calculation unit included in the arithmetic circuit. Therefore, it is possible to improve the detection accuracy of the mechanical characteristics of the analysis target position without increasing the calculation load of the ultrasonic signal processing circuit.

(2) Further, in the ultrasonic diagnostic apparatus of the above (1), the parameter calculation unit calculates the signal quality of the plurality of the acoustic line signals as the parameter, and the mechanical specific calculation unit has a high signal quality. The acoustic line signal may be selected as the plurality of analysis target signals.

With the above configuration, it is possible to detect the mechanical characteristics of the analysis target position based on the position where the acoustic line signal with high signal quality is obtained among the plurality of positions in the region of interest, and the signal quality of the acoustic line signal can be detected. It is possible to maintain a high level of detection accuracy of the mechanical characteristics of the analysis target position by suppressing the decrease in analysis accuracy due to the decrease in.

(3) Further, in the ultrasonic diagnostic apparatus of (2), the signal quality may include one or more of the signal-to-noise ratio, the signal level, and the noise level of the acoustic line signal.

With the above configuration, it is possible to maintain a high level of signal quality of the acoustic line signal that affects the detection accuracy of the mechanical characteristics of the analysis target position.

(4) Further, in the ultrasonic diagnostic apparatus of (1), the arithmetic circuit has a plurality of positions in the analysis target region based on the plurality of acoustic line signals for the analysis target region in the subject. A second mechanical characteristic calculation unit for calculating the mechanical characteristics of the above may be further provided.

With the above configuration, it is possible to determine the acquisition position of the acoustic line signal for detecting the mechanical characteristics of the analysis target position based on the spatial characteristics of the subject obtained by calculating the mechanical characteristics in the subject. It is possible to suppress the setting of an inappropriate sound line signal acquisition position and maintain a high level of detection accuracy of the mechanical characteristics of the analysis target position.

(5) Further, in the ultrasonic diagnostic apparatus of (4), the parameter calculation unit may calculate the mechanical characteristics of each of the plurality of positions in the analysis target region as the parameter.

With the above configuration, the acquisition position of the acoustic line signal for detecting the mechanical characteristics of the analysis target position can be determined based on the mechanical characteristics of the subject, and the acquisition position setting of the acoustic line signal can be optimized for analysis. It is possible to improve the detection accuracy of the mechanical characteristics of the target position.

(6) Further, in the ultrasonic diagnostic apparatus of the above (5), the parameters are the velocity of the shear wave, the shear modulus, the Young's modulus, the dynamic shear viscosity, and the mechanical at each of the plurality of positions in the analysis target region. It may include one or more of the viscosities.

With the above configuration, the acquisition position of the acoustic line signal for detecting the mechanical characteristics of the analysis target position can be determined based on the mechanical characteristics of the subject, and the acquisition position setting of the acoustic line signal can be optimized for analysis. It is possible to improve the detection accuracy of the mechanical characteristics of the target position.

(7) Further, in the ultrasonic diagnostic apparatus of the above (1) to (6), the mechanical property is any one of shear wave velocity, shear modulus, Young's modulus, dynamic shear viscosity, and mechanical impedance. , May be.

With the above configuration, it is possible to perform an absolute evaluation of the mechanical properties of the subject using an ultrasonic diagnostic apparatus.

(8) Further, in the ultrasonic diagnostic apparatus of (1) to (7), when the arithmetic circuit is not connected to the ultrasonic signal processing circuit, the mechanical characteristic calculation unit corresponds to a predetermined position. The acoustic line signal to be analyzed may be selected as a plurality of the analysis target signals.

With the above configuration, when the arithmetic circuit is not connected, the mechanical characteristics of the analysis target position can be detected without increasing the arithmetic amount.

(9) Another ultrasonic diagnostic apparatus according to the embodiment includes a push wave transmitter for transmitting a push wave for generating a displacement in the subject to the ultrasonic probe, and the push wave transmission, followed by the transmission of the push wave. A detection wave transmitter that causes the ultrasonic probe to transmit a detection wave that passes through the region of interest including the position of interest in the subject, and a reception signal based on the ultrasonic waves reflected from the region of interest in response to the detection wave. Is received from the ultrasonic probe, and based on the received signal, a detection wave receiver that generates an acoustic line signal by performing phase adjustment addition at a plurality of positions in the region of interest, and parameters based on the acoustic line signal With an arithmetic circuit connection unit that is detachably configured with the arithmetic circuit to be generated, outputs a plurality of the ultrasonic line signals to the arithmetic circuit, and receives parameters for selecting a part of the plurality of the ultrasonic line signals. The ultrasonic signal includes a mechanical characteristic calculation unit that selects a plurality of analysis target signals from the plurality of acoustic line signals and calculates the mechanical characteristics of the analysis target position based on the selected analysis target signal. An arithmetic circuit that acquires the acoustic line signal from the processing circuit and outputs parameters for selecting the analysis target signal is configured to be detachable from the ultrasonic signal processing circuit, and the mechanical characteristic calculation unit. When a plurality of the analysis target signals are selected based on the parameters when the arithmetic circuit is mounted on the ultrasonic signal processing circuit, and the arithmetic circuit is not mounted on the ultrasonic signal processing circuit. It is characterized in that the acoustic line signal corresponding to a predetermined position is selected as a plurality of the analysis target signals.

Further, another control method of the ultrasonic diagnostic apparatus according to the embodiment is a control method of the ultrasonic diagnostic apparatus in which the arithmetic circuit is detachably configured, and is a push for generating a displacement in the subject. The wave is transmitted to the ultrasonic probe, and following the transmission of the push wave, the detection wave passing through the region of interest including the analysis target position in the subject is transmitted to the ultrasonic probe, corresponding to the detection wave. A received signal based on the ultrasonic wave reflected from the region of interest is received from the ultrasonic probe, and based on the received signal, phasing addition is performed at a plurality of positions in the region of interest to generate an acoustic line signal. A process of selecting a plurality of analysis target signals from a plurality of the acoustic line signals and calculating the mechanical characteristics of the analysis target position based on the selected analysis target signals is included, and the arithmetic circuit is used in the ultrasonic diagnostic apparatus. When mounted, the control method further includes processing of outputting the plurality of the acoustic line signals to the arithmetic circuit and receiving parameters for selecting the analysis target signal, and further comprising the process of receiving the plurality of the above. In the process of selecting a plurality of the analysis target signals from the acoustic line signals, when a plurality of the analysis target signals are selected based on the parameters and the arithmetic circuit is not mounted on the ultrasonic diagnostic apparatus, the analysis target In the process of selecting a plurality of signals, the ultrasonic line signals corresponding to a predetermined position are selected as the plurality of analysis target signals.

According to the present disclosure, when the arithmetic circuit is connected to the ultrasonic diagnostic apparatus by the above configuration or method, the acoustic line signal can be selected based on the parameters generated by the parameter calculation unit included in the arithmetic circuit. Since it is possible, it is possible to increase the detection accuracy of the mechanical characteristics of the analysis target position without increasing the calculation load of the ultrasonic diagnostic apparatus. On the other hand, when the arithmetic circuit is not connected to the ultrasonic diagnostic apparatus, it is possible to detect the mechanical characteristics of the analysis target position without increasing the arithmetic amount. Therefore, the mechanical characteristics of the analysis target position can be detected regardless of the presence or absence of the arithmetic circuit, and the detection accuracy of the mechanical characteristics of the analysis target position can be improved when the arithmetic circuit is connected. It is possible to perform scalable control according to the computing power.

The ultrasonic diagnostic apparatus and the ultrasonic signal processing method according to the present disclosure are useful for measuring the mechanical properties of a subject using ultrasonic waves. Therefore, it is possible to improve the measurement accuracy of the mechanical properties of tissues and substances, and it has high utility in medical diagnostic equipment, non-destructive inspection equipment, and the like.

1000, 2000 3000 Ultrasonic diagnostic system 100, 200 Ultrasonic diagnostic device 101 Ultrasonic probe 102 Operation input unit 103 Push wave generator 104 Detected wave generator 105 Transmit beam former unit 106 multiplexer unit 107 Receive beam former unit 108, 208 Speed calculation unit 109 Data storage unit 110 B mode image generation unit 111, 262 Parameter calculation unit 112, 212 Display control unit 113, 213 Control unit 114 Display unit 150, 250 Ultrasonic signal processing circuit 160, 260 Calculation circuit 261 Map type speed Calculation unit 300 Portable main unit 301 Probe 302 Display unit 303 Cart 304 Expansion unit 305 Input unit 311 Engagement groove 312 Locking claw 313 Release button 314 Connector 321 Top plate 322 Engagement convex part 323 Connector

Claims (11)

It is provided with an ultrasonic signal processing circuit and an arithmetic circuit configured to be detachable from the ultrasonic signal processing circuit.
The ultrasonic signal processing circuit
A push wave transmitter that transmits a push wave to generate a displacement in the subject to the ultrasonic probe,
Following the transmission of the push wave, a detection wave transmission unit that causes the ultrasonic probe to transmit a detection wave that passes through the region of interest including the analysis target position in the subject.
A received signal based on the ultrasonic wave reflected from the region of interest corresponding to the detected wave is received from the ultrasonic probe, and based on the received signal, phasing addition is performed for a plurality of positions in the region of interest. A detection wave receiver that generates an ultrasonic signal, and
It includes a mechanical characteristic calculation unit that selects a plurality of analysis target signals from a plurality of the acoustic line signals and calculates the mechanical characteristics of the analysis target position based on the selected analysis target signals.
The arithmetic circuit includes a parameter calculation unit that calculates parameters for selecting the analysis target signal based on the plurality of acoustic line signals.
An ultrasonic diagnostic apparatus, characterized in that, when the arithmetic circuit is mounted on the ultrasonic signal processing circuit, the mechanical characteristic calculation unit selects a plurality of the analysis target signals based on the parameters. The parameter calculation unit calculates the signal qualities of the plurality of acoustic line signals as the parameters.
The ultrasonic diagnostic apparatus according to claim 1, wherein the mechanical specific calculation unit selects an acoustic line signal having high signal quality as a plurality of the analysis target signals. The ultrasonic diagnostic apparatus according to claim 2, wherein the signal quality includes one or more of a signal-to-noise ratio, a signal level, and a noise level of an acoustic line signal. The arithmetic circuit further includes a second mechanical characteristic calculation unit that calculates the mechanical characteristics of each of the plurality of positions in the analysis target region based on the plurality of acoustic line signals for the analysis target region in the subject. The ultrasonic diagnostic apparatus according to claim 1, wherein the ultrasonic diagnostic apparatus is provided. The ultrasonic diagnostic apparatus according to claim 4, wherein the parameter calculation unit calculates mechanical characteristics of each of a plurality of positions in the analysis target region as the parameters. 5. The parameter is characterized by including one or more of shear wave velocity, shear modulus, Young's modulus, dynamic shear viscosity, and mechanical impedance at each of a plurality of positions in the analysis target region. The described ultrasonic diagnostic apparatus. The ultrasonic wave according to any one of claims 1 to 6, wherein the mechanical property is any one of a shear wave velocity, a shear modulus, a Young's modulus, a dynamic shear viscosity, and a mechanical impedance. Diagnostic device. When the arithmetic circuit is not connected to the ultrasonic signal processing circuit, the mechanical characteristic calculation unit selects an acoustic line signal corresponding to a predetermined position as a plurality of the analysis target signals. Item 6. The ultrasonic diagnostic apparatus according to any one of Items 1 to 7. A push wave transmitter that transmits a push wave to generate a displacement in the subject to the ultrasonic probe,
Following the transmission of the push wave, a detection wave transmission unit that causes the ultrasonic probe to transmit a detection wave that passes through the region of interest including the analysis target position in the subject.
A received signal based on the ultrasonic wave reflected from the region of interest corresponding to the detected wave is received from the ultrasonic probe, and based on the received signal, phasing addition is performed for a plurality of positions in the region of interest. A detection wave receiver that generates an ultrasonic signal, and
A parameter that is detachably configured with an arithmetic circuit that generates parameters based on acoustic line signals, outputs a plurality of the acoustic line signals to the arithmetic circuit, and selects a part of the plurality of acoustic line signals. With the arithmetic circuit connection that receives
It includes a mechanical characteristic calculation unit that selects a plurality of analysis target signals from a plurality of the acoustic line signals and calculates the mechanical characteristics of the analysis target position based on the selected analysis target signals.
An arithmetic circuit that acquires the acoustic line signal from the ultrasonic signal processing circuit and outputs parameters for selecting the analysis target signal is configured to be detachable from the ultrasonic signal processing circuit.
When the arithmetic circuit is mounted on the ultrasonic signal processing circuit, the mechanical characteristic calculation unit selects a plurality of the analysis target signals based on the parameters, and the arithmetic circuit is the ultrasonic signal processing circuit. An ultrasonic diagnostic apparatus characterized in that an acoustic line signal corresponding to a predetermined position is selected as a plurality of the analysis target signals when not mounted on the device. It is a control method of an ultrasonic diagnostic apparatus including a removable arithmetic circuit.
Send a push wave to generate displacement in the subject to the ultrasonic probe,
Following the transmission of the push wave, the ultrasonic probe is made to transmit a detection wave that passes through the region of interest including the analysis target position in the subject.
A received signal based on the ultrasonic wave reflected from the region of interest corresponding to the detected wave is received from the ultrasonic probe, and based on the received signal, phasing addition is performed for a plurality of positions in the region of interest. Generates an acoustic line signal,
It includes a process of selecting a plurality of analysis target signals from a plurality of the acoustic line signals and calculating the mechanical characteristics of the analysis target position based on the selected analysis target signals.
When the arithmetic circuit is mounted, the arithmetic circuit further includes a process of causing the arithmetic circuit to calculate a parameter for selecting the analysis target signal based on the plurality of acoustic line signals, and a plurality of analysis target signals are selected. A control method of an ultrasonic diagnostic apparatus, which comprises selecting a plurality of the analysis target signals based on the parameters in the processing. It is a control method of an ultrasonic diagnostic device in which an arithmetic circuit is detachably configured.
Send a push wave to generate displacement in the subject to the ultrasonic probe,
Following the transmission of the push wave, the ultrasonic probe is made to transmit a detection wave that passes through the region of interest including the analysis target position in the subject.
A received signal based on the ultrasonic wave reflected from the region of interest corresponding to the detected wave is received from the ultrasonic probe, and based on the received signal, phasing addition is performed for a plurality of positions in the region of interest. Generates an acoustic line signal,
It includes a process of selecting a plurality of analysis target signals from a plurality of the acoustic line signals and calculating the mechanical characteristics of the analysis target position based on the selected analysis target signals.
When the arithmetic circuit is mounted on the ultrasonic diagnostic apparatus, it further includes a process of outputting a plurality of the acoustic line signals to the arithmetic circuit and receiving a parameter for selecting the analysis target signal. In addition, in the process of selecting a plurality of the analysis target signals, a plurality of the analysis target signals are selected based on the parameters.
When the arithmetic circuit is not mounted on the ultrasonic diagnostic apparatus, in the process of selecting a plurality of the analysis target signals, the acoustic line signal corresponding to a predetermined position is selected as the plurality of analysis target signals. Control method of the ultrasonic diagnostic equipment.

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