Ultrasound diagnostic device, harmonic signal acquisition method, and program

Abstract

To obtain harmonics with high accuracy while suppressing reduction in a frame rate.SOLUTION: An ultrasound diagnosis apparatus according to an embodiment includes a collection unit and a generation unit. The collection unit collects a first ultrasound signal including one or more harmonic components. By executing weighed addition processing where a coefficient distribution is applied to the first ultrasound signal for different directions of two or more dimensions, the generation unit generates a second ultrasound signal including a frequency component that becomes a ratio different from a component ratio of each order included in the first ultrasound signal at a specific frequency.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The embodiments disclosed in this specification and the drawings relate to an ultrasound diagnostic device and a method for generating an ultrasound signal. [Background technology]

[0002] In order to obtain ultrasound image data with fewer artifacts, tissue harmonic imaging (THI) using harmonic components (nonlinear signals) generated during ultrasound propagation is widely used. Usually, second harmonic components are used, but the use of third harmonic components has also been proposed. Note that Nth (N is an integer equal to or greater than 2) harmonic components are also simply referred to as Nth components or Nth harmonics. Phase modulation is used to maintain the bandwidth of harmonic components. However, since three ultrasound transmissions and receptions are required to extract the third harmonic components, the frame rate is sacrificed. To solve this problem, a method has been proposed for inferring data based on nonlinear signals (harmonic components) from data based on fundamental signals (fundamental components) using machine learning.

[0003] In the trained network used in the above machine learning, since a nonlinear signal is generated from a fundamental signal, it is difficult to accurately reproduce the nonlinear signal response from a living body. In addition, when the fundamental signal is regarded as a signal obtained by one ultrasonic transmission and reception, in order to obtain a third-order nonlinear signal, the fundamental signal obtained by one ultrasonic transmission and reception is used as input data, and the third-order nonlinear signal obtained by three ultrasonic transmission and reception is used as teacher data. However, the fundamental signal contains components of frequencies that are integer multiples of the fundamental frequency. That is, the fundamental signal has complex components. In addition, the third-order nonlinear signal is obtained by adding signals three times. Therefore, the third-order nonlinear signal is a signal that is several dB, for example, about 9.5 dB, stronger than the third-order components contained in the fundamental signal. Such signal characteristics reduce the inference accuracy of the third-order nonlinear signal from the fundamental signal. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-112400 A [Patent Document 2] JP 2020-114293 A [Patent Document 3] JP 2020-179029 A [Patent Document 4] Special Publication No. 2003-500150 Summary of the Invention [Problem to be solved by the invention]

[0005] One of the problems to be solved by the embodiments disclosed in this specification and the drawings is to obtain harmonic components with high accuracy while suppressing a decrease in frame rate. However, the problems to be solved by the embodiments disclosed in this specification and the drawings are not limited to the above problem. Problems corresponding to the effects of each configuration shown in the embodiments described later can also be positioned as other problems. [Means for solving the problem]

[0006] An ultrasonic diagnostic apparatus according to an embodiment includes an acquisition unit and a generation unit. The acquisition unit acquires a first ultrasonic signal including one or more harmonic components. The generation unit executes a weighted addition process for applying a coefficient distribution in two or more different directions to the first ultrasonic signal to generate a second ultrasonic signal including frequency components at a specific frequency that have a ratio different from the ratio of components of each order included in the first ultrasonic signal. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a block diagram showing an example of the configuration of an ultrasonic diagnostic apparatus according to the first embodiment. [Diagram 2] FIG. 2 is a diagram for explaining an example of a method for generating a trained model according to the first embodiment. [Diagram 3]FIG. 3 is a diagram for explaining an example of a method for generating input data according to the first embodiment. [Figure 4] FIG. 4 is a diagram for explaining an example of a method for generating teacher data according to the first embodiment. [Diagram 5] FIG. 5 is a diagram for explaining an example of an operation at the time of inference of the trained model according to the first embodiment. [Figure 6] FIG. 6 is a flowchart showing an example of the flow of processing executed by the ultrasound diagnostic apparatus according to the first embodiment. [Figure 7] FIG. 7 is a diagram for comparing the ultrasonic diagnostic apparatus according to the first embodiment with a conventional ultrasonic diagnostic apparatus. [Figure 8A] FIG. 8A is a diagram showing an example of an ultrasound image (B-mode image) based on an ultrasound signal as input data according to the first embodiment. [Figure 8B] FIG. 8B is a diagram showing an example of an ultrasound image (B-mode image) based on an ultrasound signal as training data according to the first embodiment. [Figure 8C] FIG. 8C is a diagram showing an example of an ultrasound image (B-mode image) based on an ultrasound signal as output data according to the first embodiment. [Figure 9] FIG. 9 is a diagram for explaining an example of a method for generating input data according to the second embodiment. [Figure 10] FIG. 10 is a diagram for explaining an example of a method for generating teacher data according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an ultrasound diagnostic apparatus and an ultrasound signal generating method according to an embodiment and modifications will be described with reference to the drawings.

[0009] (First embodiment) Fig. 1 is a block diagram showing an example of the configuration of an ultrasonic diagnostic device 1 according to the first embodiment. As shown in Fig. 1, the ultrasonic diagnostic device 1 according to the first embodiment includes a device main body 100, an ultrasonic probe 101, an input device 102, and a display 103.

[0010] The ultrasonic probe 101 has, for example, a plurality of elements (piezoelectric vibrators, piezoelectric elements). These elements generate ultrasonic waves based on a drive signal supplied from a transmission circuit 111 of a transmission / reception circuit 110 included in the device body 100. Specifically, the elements generate ultrasonic waves having a waveform corresponding to the transmission drive voltage when a voltage (transmission drive voltage) is applied by the transmission circuit 111. The waveform of the transmission drive voltage indicated by the drive signal is the waveform of the voltage applied to the plurality of elements. That is, the ultrasonic probe 101 transmits ultrasonic waves corresponding to the magnitude of the applied transmission drive voltage. The ultrasonic probe 101 also receives a reflected wave from the subject P, converts the received reflected wave into a reflected wave signal, which is an electrical signal, and outputs the reflected wave signal to the device body 100. The reflected wave signal is an example of an ultrasonic signal. The ultrasonic probe 101 also has, for example, a matching layer provided on the element, and a backing material that prevents the ultrasonic wave from propagating backward from the element. The ultrasonic probe 101 is detachably connected to the device body 100.

[0011] When ultrasonic waves are transmitted from the ultrasonic probe 101 to the subject P, the transmitted ultrasonic waves are successively reflected by discontinuous surfaces of acoustic impedance in the tissues of the subject P, and are received as reflected waves by multiple elements of the ultrasonic probe 101. The amplitude of the received reflected waves depends on the difference in acoustic impedance at the discontinuous surfaces where the ultrasonic waves are reflected. When the transmitted ultrasonic pulse is reflected by the surface of a moving body such as a moving blood flow or a heart wall, the reflected waves undergo a frequency shift due to the Doppler effect depending on the velocity component of the moving body in the ultrasonic transmission direction. Then, the ultrasonic probe 101 outputs the reflected wave signal to a receiving circuit 112 of a transmitting / receiving circuit 110 described later.

[0012] The ultrasonic probe 101 is provided detachably to the device body 100. When scanning a two-dimensional area inside the subject P (two-dimensional scanning), the operator connects, for example, a 1D array probe in which a plurality of elements are arranged in a row to the device body 100 as the ultrasonic probe 101. Types of 1D array probes include a linear ultrasonic probe, a convex ultrasonic probe, and a sector ultrasonic probe. When scanning a three-dimensional area inside the subject P (three-dimensional scanning), the operator connects, for example, a mechanical 4D probe or a 2D array probe to the device body 100 as the ultrasonic probe 101. The mechanical 4D probe is capable of two-dimensional scanning using a plurality of elements arranged in a row like the 1D array probe, and is also capable of three-dimensional scanning by swinging the plurality of elements at a predetermined angle (swing angle). The 2D array probe is capable of three-dimensional scanning using a plurality of elements arranged in a matrix, and is also capable of two-dimensional scanning by focusing and transmitting ultrasonic waves.

[0013] The input device 102 is realized by input means such as a mouse, a keyboard, a button, a panel switch, a touch command screen, a foot switch, a trackball, a joystick, etc. The input device 102 receives various setting requests from the operator of the ultrasound diagnostic apparatus 1, and transfers the received various setting requests to the apparatus main body 100.

[0014] The display 103 displays, for example, a GUI (Graphical User Interface) for the operator of the ultrasound diagnostic apparatus 1 to input various setting requests using the input device 102, and displays ultrasound images and the like based on ultrasound image data generated in the apparatus body 100. The display 103 is realized by a liquid crystal monitor, an OLED (Organic Light Emitting Diode) monitor, or the like. The display 103 is an example of a display unit.

[0015] The device body 100 generates ultrasonic image data based on a reflected wave signal transmitted from the ultrasonic probe 101. The ultrasonic image data is an example of an ultrasonic signal and an example of image data. The device body 100 can generate two-dimensional ultrasonic image data based on a reflected wave signal corresponding to a two-dimensional region of the subject P transmitted from the ultrasonic probe 101. The device body 100 can also generate three-dimensional ultrasonic image data based on a reflected wave signal corresponding to a three-dimensional region of the subject P transmitted from the ultrasonic probe 101. As shown in FIG. 1, the device body 100 has a transmission / reception circuit 110, a buffer memory 120, a B-mode processing circuit 130, a Doppler processing circuit 140, an image generation circuit 150, an image memory 160, a storage circuit 170, and a control circuit 180.

[0016] The transmission / reception circuit 110, under the control of the control circuit 180, causes the ultrasonic probe 101 to transmit ultrasonic waves and causes the ultrasonic probe 101 to receive reflected waves of the ultrasonic waves. That is, the transmission / reception circuit 110 executes scanning via the ultrasonic probe 101. Note that scanning is also called scanning, ultrasonic scanning, or ultrasonic scanning. The transmission / reception circuit 110 is an example of a transmission / reception unit. The transmission / reception circuit 110 has a transmission circuit 111 and a reception circuit 112. The transmission circuit 111 is an example of a transmission unit, and the reception circuit 112 is an example of a reception unit.

[0017] The transmission circuit 111, under the control of the control circuit 180, supplies a drive signal to the ultrasonic probe 101, causing the ultrasonic probe 101 to transmit ultrasonic waves. The transmission circuit 111 has a rate pulser generating circuit, a transmission delay circuit, and a transmission pulser. When scanning a two-dimensional region within the subject P, the transmission circuit 111 causes the ultrasonic probe 101 to transmit an ultrasonic beam for scanning the two-dimensional region. When scanning a three-dimensional region within the subject P, the transmission circuit 111 causes the ultrasonic probe 101 to transmit an ultrasonic beam for scanning the three-dimensional region.

[0018] The rate pulser generating circuit is controlled by the control circuit 180 and repeatedly generates rate pulses for forming a transmission ultrasonic wave (transmission beam) at a predetermined pulse repetition frequency (PRF). The rate pulse passes through the transmission delay circuit, so that a voltage having a different transmission delay time is applied to the transmission pulser. For example, the transmission delay circuit provides each rate pulse generated by the rate pulser generating circuit with a transmission delay time for each element required for focusing the ultrasonic waves generated from the ultrasonic probe 101 into a beam shape and determining the transmission directivity. The transmission pulser supplies a drive signal (drive pulse) to the ultrasonic probe 101 at a timing based on the rate pulse. That is, the transmission pulser applies a voltage (transmission drive voltage) having a waveform indicated by the drive signal to the ultrasonic probe 101 at a timing based on the rate pulse. The transmission delay circuit arbitrarily adjusts the transmission direction of the ultrasonic wave from the element surface by changing the transmission delay time provided to each rate pulse.

[0019] The driving pulse is transmitted from the transmitting pulser via a cable to an element in the ultrasonic probe 101, and then converted from an electrical signal to mechanical vibration in the element. That is, when a voltage is applied to an element, the element vibrates mechanically. Ultrasound generated by this mechanical vibration is transmitted inside the living body (inside the subject P). Here, the ultrasonic waves having different transmission delay times for each element are focused and propagated in a predetermined direction.

[0020] The transmission circuit 111 has a function of instantaneously changing the transmission frequency, transmission drive voltage, etc., in order to execute a predetermined scanning sequence under the control of the control circuit 180. In particular, the change in the transmission drive voltage is realized by a linear amplifier type oscillation circuit capable of instantaneously switching the value of the transmission drive voltage, or a mechanism for electrically switching multiple power supply units. The transmission frequency is, for example, the center frequency of the ultrasound to be transmitted.

[0021] The reflected wave of the ultrasonic wave transmitted by the ultrasonic probe 101 reaches an element inside the ultrasonic probe 101, and is then converted from mechanical vibration to an electrical signal (reflected wave signal) in the element, and the reflected wave signal is input to the receiving circuit 112. The receiving circuit 112 has a preamplifier, an A / D (Analog to Digital) converter, a quadrature detection circuit, etc., and performs various processes on the reflected wave signal transmitted from the ultrasonic probe 101 to generate reflected wave data. The receiving circuit 112 then stores the generated reflected wave data in the buffer memory 120. The reflected wave data is an example of an ultrasonic signal.

[0022] The preamplifier amplifies the reflected wave signal for each channel and performs gain adjustment (gain correction). The A / D converter A / D converts the gain-corrected reflected wave signal into a digital signal. The quadrature detection circuit converts the reflected wave signal, which has been converted into a digital signal, into an in-phase signal (I signal, I: In-phase) and a quadrature signal (Q signal, Q: Quadrature-phase) in the baseband. The quadrature detection circuit then stores the I signal and Q signal (IQ signal) in the buffer memory 120 as reflected wave data.

[0023] The receiving circuit 112 generates two-dimensional reflected wave data from the two-dimensional reflected wave signal transmitted from the ultrasonic probe 101. The receiving circuit 112 also generates three-dimensional reflected wave data from the three-dimensional reflected wave signal transmitted from the ultrasonic probe 101.

[0024] In this embodiment, the ultrasound diagnostic device 1 can perform various processes in real time. For example, the ultrasound probe 101 transmits one frame's worth of reflected wave signals one after another to the receiving circuit 112. Every time the receiving circuit 112 receives one frame's worth of reflected wave signals transmitted from the ultrasound probe 101, the receiving circuit 112 generates one frame's worth of reflected wave data from the one frame's worth of reflected wave signals. Every time the receiving circuit 112 generates one frame's worth of reflected wave data, the receiving circuit 112 stores one frame's worth of reflected wave data in the buffer memory 120.

[0025] The buffer memory 120 is a memory that temporarily stores the reflected wave data generated by the transmission / reception circuit 110. For example, the buffer memory 120 is configured to be able to store a predetermined number of frames of reflected wave data. Then, when a new frame of reflected wave data is generated by the reception circuit 112 while the buffer memory 120 has stored the predetermined number of frames of reflected wave data, the buffer memory 120, under the control of the reception circuit 112, discards the oldest one frame of reflected wave data and stores the newly generated one frame of reflected wave data. For example, the buffer memory 120 is realized by a semiconductor memory element such as a RAM (Random Access Memory) or a flash memory.

[0026] The B-mode processing circuit 130 reads the reflected wave data from the buffer memory 120, performs various signal processing on the read reflected wave data, and outputs the reflected wave data subjected to various signal processing as B-mode data to the image generating circuit 150. The B-mode processing circuit 130 is realized by, for example, a processor. The B-mode processing circuit 130 is an example of a B-mode processing unit. The B-mode data is also an example of an ultrasonic signal.

[0027] For example, every time one frame of reflected wave data is newly stored in the buffer memory 120, the B-mode processing circuit 130 reads out one frame of reflected wave data newly stored in the buffer memory 120. Then, the B-mode processing circuit 130 generates one frame of B-mode data by performing various signal processing on the read one frame of reflected wave data. Then, every time the B-mode processing circuit 130 generates one frame of B-mode data, it outputs the newly generated one frame of B-mode data to the image generating circuit 150. An example of various signal processing executed by the B-mode processing circuit 130 will be described below.

[0028] For example, the B-mode processing circuit 130 performs quadrature detection, logarithmic amplification, envelope detection processing, etc. on the reflected wave data read from the buffer memory 120 to generate B-mode data in which the signal strength (amplitude strength) of each sample point is expressed as luminance. Then, the B-mode processing circuit 130 outputs the generated B-mode data to the image generation circuit 150.

[0029] The Doppler processing circuit 140 reads the reflected wave data from the buffer memory 120, performs various signal processing on the read reflected wave data, and outputs the reflected wave data that has been subjected to various signal processing as Doppler data to the image generating circuit 150. The Doppler processing circuit 140 is realized by, for example, a processor. The Doppler processing circuit 140 is an example of a Doppler processing unit.

[0030] For example, every time one frame of reflected wave data is newly stored in the buffer memory 120, the Doppler processing circuit 140 reads out one frame of reflected wave data newly stored in the buffer memory 120. Then, the Doppler processing circuit 140 generates one frame of Doppler data by performing various signal processing on the read one frame of reflected wave data. Then, every time the Doppler processing circuit 140 generates one frame of Doppler data, it outputs the newly generated one frame of Doppler data to the image generating circuit 150. An example of various signal processing executed by the Doppler processing circuit 140 will be described below.

[0031] For example, the Doppler processing circuit 140 performs frequency analysis on the reflected wave data read from the buffer memory 120 to extract motion information of a moving body (blood flow, tissue, contrast agent echo components, etc.) based on the Doppler effect from the reflected wave data, and generates Doppler data indicating the extracted motion information. For example, the Doppler processing circuit 140 extracts average speed, average variance, average power value, etc. over multiple points as motion information of the moving body, and generates Doppler data indicating the extracted motion information of the moving body. The Doppler processing circuit 140 outputs the generated Doppler data to the image generation circuit 150.

[0032] Using the above-mentioned function of the Doppler processing circuit 140, the ultrasound diagnostic device 1 can execute a color Doppler method, also called a color flow mapping (CFM) method. In the color flow mapping method, ultrasonic waves are transmitted and received multiple times on multiple scanning lines. In the color flow mapping method, a moving target indicator (MTI) filter is applied to a data sequence at the same position to suppress signals (clutter signals) originating from stationary tissue or slow-moving tissue from the data sequence at the same position, and a signal (blood flow signal) originating from blood flow is extracted. In the color flow mapping method, blood flow information such as the blood flow speed (average speed), blood flow variance (average variance value), and blood flow power (average power value) are estimated from the blood flow signal. The Doppler processing circuit 140 outputs color Doppler data indicating the blood flow information estimated by the color flow mapping method to the image generating circuit 150. Note that the color Doppler data is an example of Doppler data.

[0033] The B-mode processing circuitry 130 and the Doppler processing circuitry 140 are capable of processing both two-dimensional reflected wave data and three-dimensional reflected wave data.

[0034] The image generating circuitry 150 generates various types of ultrasound image data from the B-mode data output from the B-mode processing circuitry 130 or the Doppler data output from the Doppler processing circuitry 140. The image generating circuitry 150 is realized by a processor.

[0035] For example, the image generating circuit 150 generates two-dimensional B-mode image data in which the intensity of the reflected wave is expressed as brightness from the two-dimensional B-mode data generated by the B-mode processing circuit 130. The image generating circuit 150 also generates two-dimensional Doppler image data or two-dimensional color image data in which motion information or blood flow information is visualized from the two-dimensional Doppler data or Doppler color data generated by the Doppler processing circuit 140. The two-dimensional Doppler image data in which motion information is visualized and the two-dimensional color image data in which blood flow information is visualized are velocity image data, variance image data, power image data, or image data that is a combination of these.

[0036] Here, the image generating circuit 150 generally converts (scan converts) a scan line signal sequence of ultrasonic scanning into a scan line signal sequence of a video format represented by a television or the like, and generates ultrasonic image data for display. For example, the image generating circuit 150 generates ultrasonic image data for display by performing coordinate conversion on the data output from the B-mode processing circuit 130 and the Doppler processing circuit 140 according to the ultrasonic scanning form of the ultrasonic probe 101. In addition to the scan conversion, the image generating circuit 150 may perform various image processing such as image processing (smoothing processing) for regenerating an average brightness image using a plurality of image frames after the scan conversion, and image processing (edge ​​enhancement processing) using a differential filter in the image. In addition, the image generating circuit 150 may combine character information of various parameters, scales, body marks, etc. with the ultrasonic image data.

[0037] Furthermore, the image generating circuit 150 generates three-dimensional B-mode image data by performing coordinate conversion on the three-dimensional B-mode data generated by the B-mode processing circuit 130. The image generating circuit 150 also generates three-dimensional Doppler image data by performing coordinate conversion on the three-dimensional Doppler data generated by the Doppler processing circuit 140. That is, the image generating circuit 150 generates "three-dimensional B-mode image data and three-dimensional Doppler image data" as "three-dimensional ultrasound image data (volume data)". Then, the image generating circuit 150 performs various rendering processes on the volume data to generate various types of two-dimensional image data for displaying the volume data on the display 103.

[0038] The rendering process performed by the image generating circuit 150 includes, for example, a process of generating MPR image data from volume data using a multi-planar reconstruction method (MPR). In addition, the rendering process performed by the image generating circuit 150 includes, for example, a volume rendering (VR) process of generating two-dimensional image data reflecting three-dimensional information. The image generating circuit 150 is an example of an image generating unit.

[0039] The B-mode data and the Doppler data are ultrasonic image data before the scan conversion process, and the data generated by the image generating circuit 150 is ultrasonic image data for display after the scan conversion process. The B-mode data and the Doppler data are also called raw data.

[0040] The image memory 160 is a memory that stores various image data generated by the image generating circuit 150. The image memory 160 also stores data generated by the B-mode processing circuit 130 and the Doppler processing circuit 140. The B-mode data and Doppler data stored in the image memory 160 can be called up by an operator after diagnosis, for example, and become ultrasound image data for display via the image generating circuit 150. For example, the image memory 160 is realized by a semiconductor memory element such as a RAM (Random Access Memory) or a flash memory, a hard disk, or an optical disk.

[0041] The memory circuitry 170 stores various data such as control programs for performing scanning (transmission and reception of ultrasonic waves), image processing, and display processing, diagnostic information (e.g., patient ID, doctor's findings, etc.), diagnostic protocols, and various body marks. The memory circuitry 170 is also used for storing data stored in the image memory 160 as necessary. For example, the memory circuitry 170 is realized by a semiconductor memory element such as a flash memory, a hard disk, or an optical disk.

[0042] Moreover, the storage circuitry 170 according to this embodiment stores the trained model 170a. The storage circuitry 170 may store the trained model 170a at the time of delivery of the ultrasound diagnostic device 1, or may store the trained model 170a acquired from an external device or the like after delivery of the ultrasound diagnostic device 1. The trained model 170a will be described later.

[0043] The control circuit 180 controls the overall processing of the ultrasound diagnostic device 1. Specifically, the control circuit 180 controls the processing of the transmission circuit 111, the reception circuit 112, the B-mode processing circuit 130, the Doppler processing circuit 140, and the image generation circuit 150 based on various setting requests input by the operator via the input device 102 and various control programs and various data read from the storage circuit 170. The control circuit 180 also controls the display 103 to display an ultrasound image based on ultrasound image data for display stored in the image memory 160. For example, the control circuit 180 controls the display 103 to display a B-mode image based on the B-mode image data or a color image based on the color image data. The control circuit 180 also controls the display 103 to display a color image superimposed on the B-mode image. The control circuit 180 is an example of a display control unit or a control unit. The control circuit 180 is realized by, for example, a processor.

[0044] Moreover, the control circuit 180 controls the ultrasonic probe 101 via the transmission and reception circuit 110, thereby controlling ultrasonic scanning.

[0045] The term "processor" used in the description means a circuit such as a central processing unit (CPU), a graphics processing unit (GPU), an application specific integrated circuit (ASIC), or a programmable logic device (e.g., a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), or a field programmable gate array (FPGA)). The processor reads out a program stored in the memory circuit 170 and executes the read out program to realize its function. Instead of storing the program in the memory circuit 170, the processor may be configured to directly incorporate the program in the circuit. In this case, the processor reads out and executes the program incorporated in the circuit to realize its function. Each processor in the present embodiment is not limited to being configured as a single circuit for each processor, and may be configured as a single processor by combining multiple independent circuits to realize its function. 1 (for example, the B-mode processing circuit 130, the Doppler processing circuit 140, the image generating circuit 150, and the control circuit 180) may be integrated into one processor to realize the functions. That is, the B-mode processing circuit 130, the Doppler processing circuit 140, the image generating circuit 150, and the control circuit 180 may be integrated into one processing circuit realized by a processor. Note that the transmission / reception circuit 110, the B-mode processing circuit 130, the Doppler processing circuit 140, the image generating circuit 150, and the control circuit 180 may be integrated into one processing circuit including a processor.

[0046] The entire configuration of the ultrasound diagnostic device 1 according to the first embodiment has been described above. With the above-mentioned configuration, the ultrasound diagnostic device 1 executes the process described below so as to obtain harmonic components with high accuracy while suppressing a decrease in frame rate.

[0047] 2 is a diagram for explaining an example of a method for generating the trained model 170a according to the first embodiment. The trained model 170a is a trained machine learning model obtained by making a machine learning model perform machine learning according to a model learning program based on input data and teacher data. The trained model 170a is generated by the learning device 200.

[0048] The learning device 200 includes a machine learning model such as a convolution neural network (CNN). The learning device 200 generates a trained model 170a by performing learning (supervised learning) based on input data and teacher data related to an ultrasound examination of the same position (same cross section, same part) of a subject. The trained model 170a is provided with a function to output data (output data) corresponding to the teacher data when data corresponding to the input data is input during inference. Note that the ultrasound diagnostic device 1 may have a function similar to that of the learning device 200, and the ultrasound diagnostic device 1 may generate the trained model 170a instead of the learning device 200.

[0049] A case where the machine learning model is CNN will be described. In this case, in the learning device 200, input data is input to the CNN, which is a machine learning model. The learning device 200 applies the CNN to the input data to generate output data. Then, the output data is output from the CNN. In the learning device 200, the output data is input to an evaluation function. In the learning device 200, the teacher data is also input to the evaluation function. The learning device 200 evaluates the output data generated by the CNN based on the input data and the teacher data by the evaluation function. For example, the evaluation function compares the generated output data with the teacher data and corrects the CNN coefficients (network parameters such as weights and biases) by the error backpropagation method. The evaluation by the evaluation function is fed back to the CNN. The learning device 200 repeats such a series of supervised learning based on the input data and the teacher data acquired for the same position of the subject, until, for example, the error between the output data and the teacher data becomes equal to or less than a predetermined threshold. The learning device 200 can output the learned machine learning model as a trained model.

[0050] For example, in a CNN, when input data and training data are given, coefficients are generated that convert the input data into training data from the characteristics of the input data. The more input data and training data used in machine learning, the better, and for example, several thousand or more pieces of data are desirable.

[0051] A method for generating input data and teacher data used in machine learning in the learning device 200 will be described with reference to Fig. 3 and Fig. 4. Fig. 3 is a diagram for explaining an example of a method for generating input data according to the first embodiment. Fig. 4 is a diagram for explaining an example of a method for generating teacher data according to the first embodiment.

[0052] 3, the input data is an ultrasonic signal 30 obtained by subtracting an ultrasonic signal 25 from an ultrasonic signal 20. The ultrasonic signal 20 and the ultrasonic signal 25 are obtained by the ultrasonic diagnostic device 1 transmitting and receiving ultrasonic waves twice. In the first embodiment, the case where the ultrasonic signal 20 and the ultrasonic signal 25 are reflected wave data obtained by the receiving circuit 112 will be described below.

[0053] Here, the central frequency (frequency of the fundamental wave) included in the ultrasonic wave transmitted the first time is the same as the central frequency included in the ultrasonic wave transmitted the second time. However, the phase of the central frequency included in the ultrasonic wave transmitted the first time is different from the phase of the central frequency included in the ultrasonic wave transmitted the second time by 180 degrees. Also, the position of the subject P from which the first ultrasonic wave is transmitted is the same as the position of the subject P from which the second ultrasonic wave is transmitted. In other words, the scanning area of ​​the subject P scanned by the first ultrasonic transmission / reception is the same as the scanning area of ​​the subject P scanned by the second ultrasonic transmission / reception.

[0054] For example, in the first ultrasonic transmission / reception, the ultrasonic probe 101 transmits a transmission ultrasonic wave with a center frequency phase of 0 degrees to a predetermined position of the subject P, receives a reflected wave from the subject P, and transmits a reflected wave signal to the device body 10. This reflected wave signal contains harmonic components that are not contained in the transmitted ultrasonic wave because the subject P has nonlinear characteristics.

[0055] In the first embodiment, the reception band of the ultrasonic probe 101 does not include frequencies corresponding to fourth or higher harmonic components. Therefore, the reflected wave signal output from the ultrasonic probe 101 includes, in addition to the fundamental wave component, first, second, and third harmonic components, but does not include fourth or higher harmonic components.

[0056] For example, as shown in FIG. 3, an ultrasonic signal 20 obtained by a first ultrasonic transmission / reception contains a fundamental wave component 21, a second harmonic component 22, and a third harmonic component 23.

[0057] Also, for example, in the second ultrasonic transmission / reception, the ultrasonic probe 101 transmits a transmission ultrasonic wave having a phase of 180 degrees of the center frequency to a predetermined position of the subject P, receives a reflected wave from the subject P, and transmits a reflected wave signal to the device body 10. The ultrasonic signal 25 obtained by the second ultrasonic transmission / reception contains a fundamental wave component 26, a second harmonic component 27, and a third harmonic component 28.

[0058] 3, the phase corresponding to fundamental wave component 21 is different from the phase corresponding to fundamental wave component 26 by 180 degrees. In addition, the phase corresponding to third harmonic component 23 is different from the phase corresponding to third harmonic component 28 by 180 degrees. On the other hand, the phase corresponding to second harmonic component 22 is the same as the phase corresponding to second harmonic component 27.

[0059] Therefore, the ultrasonic signal 30 contains a fundamental wave component 31 and a third harmonic component 32, but does not contain a second harmonic component. In other words, the ultrasonic signal 30 is a signal in which the fundamental wave component and the third harmonic component are emphasized and the second harmonic component is suppressed.

[0060] Learning device 200 is connected to ultrasound diagnostic device 1, acquires ultrasound signal 20 and ultrasound signal 25 from ultrasound diagnostic device 1, generates ultrasound signal 30 by subtracting ultrasound signal 25 from ultrasound signal 20, and uses generated ultrasound signal 30 as input data. Note that learning device 200 may also acquire ultrasound signal 30 generated by ultrasound diagnostic device 1 and use the acquired ultrasound signal 30 as input data.

[0061] 4, the teacher data is an ultrasonic signal 55 obtained by adding together ultrasonic signals 40, 45, and 50. The ultrasonic signals 40, 45, and 50 are obtained by the ultrasonic diagnostic device 1 transmitting and receiving ultrasonic waves three times. In the first embodiment, the case where the ultrasonic signals 40, 45, and 50 are reflected wave data obtained by the receiving circuit 112 will be described below.

[0062] Here, the center frequency included in the ultrasonic wave transmitted the first time, the center frequency included in the ultrasonic wave transmitted the second time, and the center frequency included in the ultrasonic wave transmitted the third time are the same. However, the phase of the center frequency included in the ultrasonic wave transmitted the first time and the phase of the center frequency included in the ultrasonic wave transmitted the second time differ by 120 degrees. Also, the phase of the center frequency included in the ultrasonic wave transmitted the first time and the phase of the center frequency included in the ultrasonic wave transmitted the third time differ by 240 degrees.

[0063] Furthermore, the subject P to which ultrasonic waves are transmitted when the input data is generated is the same as the subject P to which ultrasonic waves are transmitted when the teacher data is generated. Furthermore, the position of the subject P to which ultrasonic waves are transmitted when the input data is generated is the same as the position of the subject P to which ultrasonic waves are transmitted when the teacher data is generated. In other words, the scanning area of ​​the subject P when the input data is generated is the same as the scanning area of ​​the subject P when the teacher data is generated.

[0064] Furthermore, the position of the subject P to which the first ultrasonic wave is transmitted, the position of the subject P to which the second ultrasonic wave is transmitted, and the position of the subject P to which the third ultrasonic wave is transmitted are the same. That is, the scanning area of ​​the subject P scanned by the first ultrasonic transmission / reception, the scanning area of ​​the subject P scanned by the second ultrasonic transmission / reception, and the scanning area of ​​the subject P scanned by the third ultrasonic transmission / reception are the same.

[0065] For example, in the first ultrasonic transmission / reception, the ultrasonic probe 101 transmits an ultrasonic wave having a center frequency with a phase of 0 degrees to a predetermined position of the subject P, receives a reflected wave from the subject P, and transmits a reflected wave signal to the device body 10. The ultrasonic signal 40 obtained by the first ultrasonic transmission / reception contains a fundamental wave component 41, a second harmonic component 42, and a third harmonic component 43.

[0066] Also, for example, in the second ultrasonic transmission / reception, the ultrasonic probe 101 transmits a transmission ultrasonic wave having a phase of 120 degrees at the center frequency to a predetermined position of the subject P, receives a reflected wave from the subject P, and transmits a reflected wave signal to the device body 10. The ultrasonic signal 45 obtained by the second ultrasonic transmission / reception contains a fundamental wave component 46, a second harmonic component 47, and a third harmonic component 48.

[0067] Also, for example, in the third ultrasonic transmission / reception, the ultrasonic probe 101 transmits a transmission ultrasonic wave having a phase of 240 degrees at the center frequency to a predetermined position of the subject P, receives a reflected wave from the subject P, and transmits a reflected wave signal to the device body 10. The ultrasonic signal 50 obtained by the third ultrasonic transmission / reception contains a fundamental wave component 51, a second harmonic component 52, and a third harmonic component 53.

[0068] 4, the phase corresponding to fundamental wave component 41, the phase corresponding to fundamental wave component 46, and the phase corresponding to fundamental wave component 51 are all 120 degrees different from each other. Also, the phase corresponding to second harmonic component 42, the phase corresponding to second harmonic component 47, and the phase corresponding to second harmonic component 52 are all 120 degrees different from each other. On the other hand, the phase corresponding to third harmonic component 43, the phase corresponding to third harmonic component 48, and the phase corresponding to third harmonic component 53 are the same.

[0069] Therefore, ultrasonic signal 55 contains third harmonic component 56, but does not contain fundamental wave component and second harmonic component. In other words, ultrasonic signal 55 is a signal in which the third harmonic component is emphasized and the fundamental wave component and second harmonic component are suppressed.

[0070] The learning device 200 acquires the ultrasound signal 40, the ultrasound signal 45, and the ultrasound signal 50 from the ultrasound diagnostic device 1, generates the ultrasound signal 55 by adding the ultrasound signal 40, the ultrasound signal 45, and the ultrasound signal 50, and uses the generated ultrasound signal 55 as training data. Note that the learning device 200 may also acquire the ultrasound signal 55 generated by the ultrasound diagnostic device 1, and use the acquired ultrasound signal 55 as training data.

[0071] The learning device 200 generates a trained model 170a using the input data (ultrasound signal 30) and teacher data (ultrasound signal 55) generated by the method described above. At this time, the learning device 200 generates a trained model 170a for each part to be scanned. Then, the ultrasound diagnostic device 1 acquires the trained model 170a generated for each part from the learning device 200, and stores the acquired trained model 170a for each part in the memory circuitry 170. Then, at the time of inference, the ultrasound diagnostic device 1 acquires the trained model 170a corresponding to the part to be scanned from the memory circuitry 170, infers output data corresponding to the input data using the acquired trained model 170a, and outputs the inferred output data.

[0072] For example, the trained model 170a generated by the learning device 200 is realized by the above-mentioned CNN. In this case, during inference, the trained model 170a generates output data by performing a convolution process using a filter of a predetermined kernel size on input data and a deconvolution process using a filter of a predetermined kernel size, and outputs the generated output data.

[0073] FIG. 5 is a diagram for explaining an example of the operation of the trained model 170a according to the first embodiment during inference. As shown in FIG. 5, the receiving circuit 112 of the ultrasound diagnostic device 1 generates an ultrasound signal 60. That is, the ultrasound probe 101 and the transmitting / receiving circuit 110 collect the ultrasound signal 60 including two different fundamental wave components and harmonic components. In this way, the ultrasound signal 60 includes a fundamental wave component and at least one harmonic component. In addition, the ultrasound signal 60 includes two different frequency components. In this way, the ultrasound probe 101 and the transmitting / receiving circuit 110 have a function of collecting the ultrasound signal 60, and therefore are an example of a collecting unit. The ultrasound signal 60 is an example of a first ultrasound signal.

[0074] Furthermore, the receiving circuit 112 acquires the trained model 170a corresponding to the part to be scanned from the trained models 170a for each part stored in the storage circuit 170. The receiving circuit 112 then inputs the generated ultrasound signal 60 to the acquired trained model 170a. The ultrasound signal 60 is generated by a method similar to the method of generating the ultrasound signal 30 shown in FIG. 3 above. That is, during inference, the ultrasound diagnostic device 1 transmits and receives ultrasound twice, and the receiving circuit 112 generates the ultrasound signal 60 by subtracting the ultrasound signal (reflected wave data) obtained by the second ultrasound transmission and reception from the ultrasound signal (reflected wave data) obtained by the first ultrasound transmission and reception. The trained model 170a is an example of a generating unit. The receiving circuit 112 is also an example of a generating unit.

[0075] In other words, at the time of inference, the ultrasonic diagnostic device 1 transmits ultrasonic waves twice, with the phase of the center frequency of the transmitted ultrasonic waves being different for each transmission, and generates an ultrasonic signal 60 by subtracting one ultrasonic signal obtained by the second ultrasonic transmission / reception from one ultrasonic signal obtained by the first ultrasonic transmission / reception, among a plurality (two) ultrasonic signals obtained by the two ultrasonic transmissions. Here, the phase of the center frequency of the ultrasonic waves transmitted the first time differs from the phase of the center frequency of the ultrasonic waves transmitted the second time by 180 degrees. The ultrasonic signal 60 includes a fundamental wave component 61 and a third harmonic component 62. That is, the ultrasonic signal 60 is a signal in which the fundamental wave component 61 and the third harmonic component 62 are emphasized. In this way, the ultrasonic signal 60 is an ultrasonic signal in which odd-order components (odd-order harmonic components) are emphasized.

[0076] When an ultrasonic signal 60 is input as input data, the trained model 170a generates an ultrasonic signal 65 corresponding to the ultrasonic signal 60, and outputs the generated ultrasonic signal 65 as output data. The ultrasonic signal 65 is an example of a second ultrasonic signal.

[0077] The ultrasonic signal 65 includes a third harmonic component 66. The ultrasonic signal 65 is a signal equivalent to teacher data. For example, the ultrasonic signal 65 is an ultrasonic signal in which a specific harmonic component (third harmonic component 66) is emphasized, which is obtained by adding a plurality (three) of ultrasonic signals obtained by transmitting ultrasonic waves three times, each of which has a different phase of the center frequency of the transmitted ultrasonic waves. That is, the ultrasonic signal 65 is an ultrasonic signal in which a harmonic component of an order that is a multiple of three is emphasized. Here, the phase of the center frequency of the ultrasonic waves transmitted the first time, the phase of the center frequency of the ultrasonic waves transmitted the second time, and the phase of the center frequency of the ultrasonic waves transmitted the third time are different from each other by 120 degrees.

[0078] The ultrasonic signal 65 is treated as reflected wave data. Therefore, the control circuit 180 causes the display 103 to display a B-mode image based on the ultrasonic signal 65. Here, the B-mode image based on the ultrasonic signal 65 is, for example, a B-mode image based on B-mode image data obtained from the ultrasonic signal 65.

[0079] As described above, in the first embodiment, the learning device 200 trains the trained model 170a using the ultrasound signal 30 including the third harmonic component 32 as input data. Therefore, the ultrasound diagnostic device 1 according to the first embodiment can obtain the ultrasound signal 65 (output data) including the highly accurate third harmonic component 66 as reflected wave data by using the ultrasound signal 60 including the third harmonic component 62 as input data input to the trained model 170a during inference. It can be said that the ultrasound signal 65 is a signal in which the fundamental wave component included in the ultrasound signal 60 is suppressed and the third harmonic component is maintained.

[0080] Fig. 6 is a flowchart showing the flow of an example of processing executed by the ultrasound diagnostic device 1 according to the first embodiment. The processing shown in Fig. 6 is an example of processing in which the ultrasound diagnostic device 1 generates an ultrasound signal 65 and displays an ultrasound image based on the ultrasound signal 65 on the display 103.

[0081] As shown in FIG. 6, the ultrasound diagnostic device 1 generates an ultrasound signal (a third ultrasound signal) similar to the ultrasound signal 20 by a method similar to the method for generating the ultrasound signal 20 (step S101).

[0082] Then, the ultrasonic diagnostic device 1 generates an ultrasonic signal (fourth ultrasonic signal) similar to the ultrasonic signal 25 by the same method as the method for generating the ultrasonic signal 25 (step S102).

[0083] Then, the receiving circuit 112 generates the ultrasonic signal 60 by subtracting the fourth ultrasonic signal generated in step S102 from the third ultrasonic signal generated in step S101 (step S103).

[0084] Then, the receiving circuit 112 inputs the ultrasonic signal 60 as input data to the trained model 170a, and acquires the ultrasonic signal 65 including the third harmonic component output from the trained model 170a as output data (step S104).

[0085] Then, the control circuit 180 causes the display 103 to display an ultrasound image (B-mode image) based on the ultrasound signal 65 (step S105).

[0086] Then, the control circuit 180 determines whether or not to continue the scan (step S106). If the scan is to be continued (step S106: Yes), the ultrasound diagnostic apparatus 1 returns to step S101 and executes the processes of steps S101 to S106 again. Note that the processes of steps S101 to S106 are executed for each frame of the ultrasound image displayed on the display 103. As a result, the ultrasound image is displayed on the display 103 as a moving image.

[0087] Therefore, during inference, the trained model 170a generates an ultrasound signal 65 by performing a weighted addition process that applies a coefficient distribution in two different directions (sample direction and beam direction) to the ultrasound signal 60 input as input data. The trained model 170a then outputs the ultrasound signal 65 obtained by performing the weighted addition process as output data.

[0088] If scanning is not to be continued (step S106: No), the ultrasound diagnostic apparatus 1 ends the process shown in FIG.

[0089] 7 is a diagram for comparing the ultrasonic diagnostic device 1 according to the first embodiment with a conventional ultrasonic diagnostic device. For example, a case will be described in which the conventional ultrasonic diagnostic device applies a frequency filter to an ultrasonic signal 60 to suppress a fundamental wave component 61 and a third harmonic component 62. In this case, the fundamental wave component (represented by a black circle in FIG. 7) corresponding to a frequency fx in a frequency band common to the frequency band of the fundamental wave component 61 and the frequency band of the third harmonic component 62, and the third harmonic component (represented by a white circle in FIG. 7) corresponding to the frequency fx are suppressed at the same rate.

[0090] For this reason, in conventional ultrasonic diagnostic devices, the ratio of the fundamental wave component corresponding to frequency fx contained in ultrasonic signal 60 to the third harmonic component corresponding to frequency fx does not change before and after the frequency filter is applied.

[0091] On the other hand, in the ultrasound diagnostic device 1 according to the first embodiment, the ultrasound signal 60 includes a fundamental component 61 and a third harmonic component 62. However, the ultrasound signal 65 generated by the trained model 170a includes the third harmonic component 62 but does not include a fundamental component. Therefore, by generating such an ultrasound signal 65, the ultrasound diagnostic device 1 can obtain a high-quality ultrasound image with less side lobe effects compared to an ultrasound image based on the fundamental component. In addition, the ultrasound diagnostic device 1 can obtain the ultrasound signal 65 while suppressing the fundamental component, which is an unnecessary component, and maintaining the frequency band of the third harmonic component 62.

[0092] In this way, in the ultrasonic diagnostic device 1 according to the first embodiment, at a specific frequency fx, the ratio of each frequency component (fundamental wave component and third harmonic component) included in the ultrasonic signal 60 differs from the ratio of each frequency component (fundamental wave component and third harmonic component) in the ultrasonic signal 65. That is, the ultrasonic diagnostic device 1 generates an ultrasonic signal 65 including frequency components having a different ratio from the component ratio of each order included in the ultrasonic signal 60 at a specific frequency fx. In addition, the ultrasonic diagnostic device 1 generates an ultrasonic signal 65 including a fundamental wave component and at least one harmonic component having a different ratio from the ratio of the fundamental wave component and at least one harmonic component included in the ultrasonic signal 60 at a specific frequency fx.

[0093] Fig. 8A is a diagram showing an example of an ultrasound image (B-mode image) 68 based on an ultrasound signal 60 as input data according to the first embodiment. Fig. 8B is a diagram showing an example of an ultrasound image (B-mode image) 69 based on an ultrasound signal 55 as teacher data according to the first embodiment. Fig. 8C is a diagram showing an example of an ultrasound image (B-mode image) 70 based on an ultrasound signal 65 as output data according to the first embodiment.

[0094] As can be seen by comparing Figures 8A to 8C, ultrasound image 68 contains not only third harmonic components but also fundamental components, but in ultrasound image 70, similar to ultrasound image 69, the fundamental components are suppressed and the third harmonic components are maintained.

[0095] The ultrasound diagnostic device 1 according to the first embodiment has been described above. In the ultrasound diagnostic device 1, during inference, the ultrasound signal 65 is generated using the ultrasound signal 60 obtained by two ultrasound transmissions and receptions, rather than three ultrasound transmissions and receptions. Therefore, the ultrasound diagnostic device 1 according to the first embodiment can obtain the third harmonic component 66 with high accuracy while suppressing a decrease in frame rate.

[0096] Second embodiment The ultrasonic diagnostic device 1 according to the second embodiment will be described below. In the description of the ultrasonic diagnostic device 1 according to the second embodiment, the description of the configuration similar to that of the ultrasonic diagnostic device 1 according to the first embodiment will be omitted, and the differences from the configuration of the ultrasonic diagnostic device 1 according to the first embodiment will be mainly described.

[0097] In the second embodiment, the reception band of the ultrasonic probe 101 does not include frequencies corresponding to the fifth or higher harmonic components. Therefore, the reflected wave signal output from the ultrasonic probe 101 includes, in addition to the fundamental wave component, the first, second, third, and fourth harmonic components, but does not include the fifth or higher harmonic components.

[0098] The trained model 170a according to the second embodiment is a trained machine learning model obtained by making a machine learning model perform machine learning according to a model learning program based on input data and teacher data, similar to the trained model 170a according to the second embodiment. The trained model 170a according to the second embodiment is generated by the learning device 200.

[0099] The learning device 200 generates a trained model 170a according to the second embodiment by performing learning (supervised learning) based on input data and teacher data related to an ultrasound examination of the same position (same cross section, same site) of a subject. The trained model 170a is provided with a function to output data (output data) corresponding to the teacher data when data corresponding to the input data is input during inference. Note that the ultrasound diagnostic device 1 may have a function similar to that of the learning device 200, and the ultrasound diagnostic device 1 may generate the trained model 170a instead of the learning device 200.

[0100] In the second embodiment, a method for generating input data and teacher data used in machine learning in the learning device 200 will be described with reference to Fig. 9 and Fig. 10. Fig. 9 is a diagram for explaining an example of a method for generating input data according to the second embodiment. Fig. 10 is a diagram for explaining an example of a method for generating teacher data according to the second embodiment.

[0101] 9, the input data is an ultrasonic signal 81 obtained by adding ultrasonic signals 71 and 76. The ultrasonic signals 71 and 76 are obtained by two ultrasonic transmissions and receptions by the ultrasonic diagnostic device 1. In the second embodiment, a case will be described below in which the ultrasonic signals 71 and 76 are reflected wave data obtained by the receiving circuit 112.

[0102] Here, the central frequency included in the ultrasonic wave transmitted the first time is the same as the central frequency included in the ultrasonic wave transmitted the second time. However, the phase of the central frequency included in the ultrasonic wave transmitted the first time is different from the phase of the central frequency included in the ultrasonic wave transmitted the second time by 180 degrees. Also, the position of the subject P from which the first ultrasonic wave is transmitted is the same as the position of the subject P from which the second ultrasonic wave is transmitted. In other words, the scanning area of ​​the subject P scanned by the first ultrasonic transmission / reception is the same as the scanning area of ​​the subject P scanned by the second ultrasonic transmission / reception.

[0103] For example, in the first ultrasonic transmission / reception, the ultrasonic probe 101 transmits a transmission ultrasonic wave with a center frequency phase of 0 degrees to a predetermined position of the subject P, receives a reflected wave from the subject P, and transmits a reflected wave signal to the device body 10. This reflected wave signal contains harmonic components that are not contained in the transmitted ultrasonic wave because the subject P has nonlinear characteristics.

[0104] For example, as shown in FIG. 9, an ultrasonic signal 71 obtained by a first ultrasonic transmission / reception contains a fundamental wave component 72, a second harmonic component 73, a third harmonic component 74, and a fourth harmonic component 75.

[0105] Also, for example, in the second ultrasonic transmission / reception, the ultrasonic probe 101 transmits a transmission ultrasonic wave having a phase of 180 degrees of the center frequency to a predetermined position of the subject P, receives a reflected wave from the subject P, and transmits a reflected wave signal to the device body 10. The ultrasonic signal 76 obtained by the second ultrasonic transmission / reception contains a fundamental wave component 77, a second harmonic component 78, a third harmonic component 79, and a fourth harmonic component 80.

[0106] 9, the phase corresponding to fundamental wave component 72 is different from the phase corresponding to fundamental wave component 77 by 180 degrees. In addition, the phase corresponding to third harmonic component 74 is different from the phase corresponding to third harmonic component 79 by 180 degrees. On the other hand, the phase corresponding to second harmonic component 73 is the same as the phase corresponding to second harmonic component 78. The phase corresponding to fourth harmonic component 75 is the same as the phase corresponding to fourth harmonic component 80.

[0107] Therefore, ultrasonic signal 81 contains second harmonic component 82 and fourth harmonic component 83, but does not contain fundamental wave component and third harmonic component. In other words, ultrasonic signal 81 is a signal in which the second harmonic component and fourth harmonic component are emphasized and the fundamental wave component and third harmonic component are suppressed.

[0108] The learning device 200 acquires the ultrasound signal 71 and the ultrasound signal 76 from the ultrasound diagnostic device 1, generates the ultrasound signal 81 by adding the ultrasound signal 76 to the ultrasound signal 71, and uses the generated ultrasound signal 81 as input data. Note that the learning device 200 may also acquire the ultrasound signal 81 generated by the ultrasound diagnostic device 1 and use the acquired ultrasound signal 81 as input data.

[0109] 10, the teacher data is ultrasonic signal 109 obtained by adding ultrasonic signal 84, ultrasonic signal 89, ultrasonic signal 94, and ultrasonic signal 104. Ultrasonic signal 84, ultrasonic signal 89, ultrasonic signal 94, and ultrasonic signal 104 are obtained by ultrasonic diagnostic device 1 transmitting and receiving ultrasonic waves four times. In the second embodiment, a case will be described below in which ultrasonic signal 84, ultrasonic signal 89, ultrasonic signal 94, and ultrasonic signal 104 are reflected wave data obtained by receiving circuit 112.

[0110] Here, the central frequency included in the ultrasonic wave transmitted the first time, the central frequency included in the ultrasonic wave transmitted the second time, the central frequency included in the ultrasonic wave transmitted the third time, and the central frequency included in the ultrasonic wave transmitted the fourth time are the same. However, the phase of the central frequency included in the ultrasonic wave transmitted the first time and the phase of the central frequency included in the ultrasonic wave transmitted the second time are different by 90 degrees. Moreover, the phase of the central frequency included in the ultrasonic wave transmitted the first time and the phase of the central frequency included in the ultrasonic wave transmitted the third time are different by 180 degrees. Moreover, the phase of the central frequency included in the ultrasonic wave transmitted the first time and the phase of the central frequency included in the ultrasonic wave transmitted the fourth time are different by 270 degrees.

[0111] Furthermore, the subject P to which ultrasonic waves are transmitted when the input data is generated is the same as the subject P to which ultrasonic waves are transmitted when the teacher data is generated. Furthermore, the position of the subject P to which ultrasonic waves are transmitted when the input data is generated is the same as the position of the subject P to which ultrasonic waves are transmitted when the teacher data is generated. In other words, the scanning area of ​​the subject P when the input data is generated is the same as the scanning area of ​​the subject P when the teacher data is generated.

[0112] Furthermore, the position of the subject P from which the first ultrasonic wave is transmitted, the position of the subject P from which the second ultrasonic wave is transmitted, the position of the subject P from which the third ultrasonic wave is transmitted, and the position of the subject P from which the fourth ultrasonic wave is transmitted are the same. That is, the scanning area of ​​the subject P scanned by the first ultrasonic transmission / reception, the scanning area of ​​the subject P scanned by the second ultrasonic transmission / reception, the scanning area of ​​the subject P scanned by the third ultrasonic transmission / reception, and the scanning area of ​​the subject P scanned by the fourth ultrasonic transmission / reception are the same.

[0113] For example, in the first ultrasonic transmission / reception, the ultrasonic probe 101 transmits a transmission ultrasonic wave having a center frequency with a phase of 0 degrees to a predetermined position of the subject P, receives a reflected wave from the subject P, and transmits a reflected wave signal to the device body 10. An ultrasonic signal 84 obtained by the first ultrasonic transmission / reception contains a fundamental wave component 85, a second harmonic component 86, a third harmonic component 87, and a fourth harmonic component 88.

[0114] Also, for example, in the second ultrasonic transmission / reception, the ultrasonic probe 101 transmits a transmission ultrasonic wave having a phase of 90 degrees at the center frequency to a predetermined position on the subject P, receives a reflected wave from the subject P, and transmits a reflected wave signal to the device body 10. The ultrasonic signal 89 obtained by the second ultrasonic transmission / reception contains a fundamental wave component 90, a second harmonic component 91, a third harmonic component 92, and a fourth harmonic component 93.

[0115] Also, for example, in the third ultrasonic transmission / reception, the ultrasonic probe 101 transmits a transmission ultrasonic wave having a phase of 180 degrees of the center frequency to a predetermined position of the subject P, receives a reflected wave from the subject P, and transmits a reflected wave signal to the device body 10. The ultrasonic signal 94 obtained by the third ultrasonic transmission / reception contains a fundamental wave component 95, a second harmonic component 96, a third harmonic component 97, and a fourth harmonic component 98.

[0116] Also, for example, in the fourth ultrasonic transmission / reception, the ultrasonic probe 101 transmits a transmission ultrasonic wave having a phase of 270 degrees at the center frequency to a predetermined position of the subject P, receives a reflected wave from the subject P, and transmits a reflected wave signal to the device body 10. The ultrasonic signal 104 obtained by the fourth ultrasonic transmission / reception contains a fundamental wave component 105, a second harmonic component 106, a third harmonic component 107, and a fourth harmonic component 108.

[0117] 10, the phase corresponding to fundamental wave component 85 and the phase corresponding to fundamental wave component 95 are different from each other by 180 degrees. Also, the phase corresponding to fundamental wave component 90 and the phase corresponding to fundamental wave component 105 are different from each other by 180 degrees.

[0118] Moreover, the phase corresponding to the second harmonic component 86 and the phase corresponding to the second harmonic component 91 are different from each other by 180 degrees. Moreover, the phase corresponding to the second harmonic component 96 and the phase corresponding to the second harmonic component 106 are different from each other by 180 degrees.

[0119] Moreover, the phase corresponding to the third harmonic component 87 and the phase corresponding to the third harmonic component 97 are different from each other by 180 degrees. Moreover, the phase corresponding to the third harmonic component 92 and the phase corresponding to the third harmonic component 107 are different from each other by 180 degrees.

[0120] Furthermore, the phase corresponding to the fourth harmonic component 88, the phase corresponding to the fourth harmonic component 93, the phase corresponding to the fourth harmonic component 98, and the phase corresponding to the fourth harmonic component 108 are the same.

[0121] Therefore, ultrasonic signal 109 contains fourth harmonic component 113, but does not contain fundamental, second, or third harmonic components. In other words, ultrasonic signal 109 is a signal in which the fourth harmonic component is emphasized and the fundamental, second, and third harmonic components are suppressed.

[0122] Learning device 200 acquires ultrasound signal 84, ultrasound signal 89, ultrasound signal 94, and ultrasound signal 104 from ultrasound diagnostic device 1, generates ultrasound signal 109 by adding ultrasound signal 84, ultrasound signal 89, ultrasound signal 94, and ultrasound signal 104, and uses generated ultrasound signal 109 as teacher data. Note that learning device 200 may also acquire ultrasound signal 109 generated by ultrasound diagnostic device 1, and use the acquired ultrasound signal 109 as teacher data.

[0123] The learning device 200 generates a trained model 170a according to the second embodiment using input data (ultrasound signal 81) and teacher data (ultrasound signal 109) generated by the above-mentioned method. At this time, the learning device 200 generates a trained model 170a for each part to be scanned. Then, the ultrasound diagnostic device 1 acquires the trained model 170a generated for each part from the learning device 200, and stores the acquired trained model 170a for each part in the memory circuitry 170. Then, at the time of inference, the ultrasound diagnostic device 1 acquires the trained model 170a corresponding to the part to be scanned from the memory circuitry 170, infers output data corresponding to the input data using the acquired trained model 170a, and outputs the inferred output data.

[0124] Next, an example of the operation of the trained model 170a according to the second embodiment at the time of inference will be described. The ultrasound diagnostic device 1 generates an ultrasound signal as input data to be input to the trained model 170a at the time of inference, by a method similar to the method for generating the ultrasound signal 81 shown in FIG. 9 above. The ultrasound signal generated in this way is an example of a first ultrasound signal. In the following description, the ultrasound signal generated in this way may be referred to as "ultrasound signal as input data at the time of inference."

[0125] Furthermore, the receiving circuitry 112 acquires the trained model 170a corresponding to the part to be scanned from the trained models 170a for each part stored in the storage circuitry 170. The receiving circuitry 112 then inputs an ultrasound signal as input data at the time of inference to the acquired trained model 170a. That is, at the time of inference, the ultrasound diagnostic device 1 transmits and receives ultrasound twice, and the receiving circuitry 112 generates an ultrasound signal as input data at the time of inference by adding an ultrasound signal (reflected wave data) obtained by the first ultrasound transmission and reception and an ultrasound signal (reflected wave data) obtained by the second ultrasound transmission and reception.

[0126] The ultrasonic signal as input data during inference includes a second harmonic component and a fourth harmonic component. That is, the ultrasonic signal as input data during inference is a signal in which the second harmonic component and the fourth harmonic component are emphasized. In this way, the ultrasonic signal as input data during inference is an ultrasonic signal in which even-order harmonic components are emphasized.

[0127] When an ultrasonic signal is input as input data at the time of inference, the trained model 170a generates an ultrasonic signal corresponding to the ultrasonic signal as input data at the time of inference, and outputs the generated ultrasonic signal as output data. The ultrasonic signal thus output from the trained model 170a is an example of a second ultrasonic signal. In the following description, the ultrasonic signal thus output from the trained model 170a may be referred to as "ultrasonic signal as output data at the time of inference."

[0128] The ultrasonic signal as output data during inference includes a fourth-order harmonic component. The ultrasonic signal as output data during inference is a signal equivalent to teacher data. For example, the ultrasonic signal as output data during inference is an ultrasonic signal in which a specific harmonic component (fourth-order harmonic component) is emphasized, which is obtained by adding multiple (four) ultrasonic signals obtained by transmitting ultrasonic waves four times, each of which has a different phase of the center frequency of the transmitted ultrasonic waves. In other words, the ultrasonic signal as output data during inference is an ultrasonic signal in which harmonic components of orders that are multiples of four are emphasized.

[0129] The ultrasonic signal as output data during inference is treated as reflected wave data. Therefore, the control circuit 180 causes the display 103 to display a B-mode image based on the ultrasonic signal as output data during inference.

[0130] As described above, in the second embodiment, the learning device 200 trains the trained model 170a using the ultrasound signal 81 including the fourth harmonic component 83 as input data. Therefore, the ultrasound diagnostic device 1 according to the second embodiment can obtain an ultrasound signal including a high-precision fourth harmonic component (ultrasound signal as output data during inference) as reflected wave data by using an ultrasound signal including a fourth harmonic component as input data input to the trained model 170a during inference. It can be said that the ultrasound signal as output data during inference is a signal in which the second harmonic component included in the ultrasound signal as input data during inference is suppressed and the fourth harmonic component is maintained.

[0131] The ultrasonic diagnostic device 1 according to the second embodiment has been described above. In the ultrasonic diagnostic device 1, an ultrasonic signal serving as input data during inference obtained by two ultrasonic transmissions and receptions, rather than four ultrasonic transmissions and receptions, is used to generate an ultrasonic signal serving as output data during inference. Therefore, the ultrasonic diagnostic device 1 according to the second embodiment can obtain a fourth harmonic component with high accuracy while suppressing a decrease in frame rate.

[0132] (Modification) In the above-described first and second embodiments, a case has been described in which the trained model 170a performs a weighted addition process in which a coefficient distribution is applied to input data in two different directions (sample direction and beam direction) during inference. However, the trained model 170a may perform a weighted addition process in which a coefficient distribution is applied to input data in two or more different directions (sample direction, beam direction, and other directions) during inference.

[0133] In the above-described first and second embodiments, the output data is obtained by adding up a plurality of ultrasonic signals. However, the output data may be an ultrasonic signal obtained by subtracting one of the plurality of ultrasonic signals from another ultrasonic signal so that a specific harmonic component is emphasized and included.

[0134] In the above-mentioned first and second embodiments, the input data, teacher data, and output data are described as reflected wave data. However, the input data, teacher data, and output data may be B-mode data or B-mode image data. That is, the ultrasound diagnostic device 1 may use the B-mode data or B-mode image data obtained by the B-mode processing circuit 130 or the image generating circuit 150 based on the ultrasound signal 30, the ultrasound signal 60, or the ultrasound signal 81 as input data. The ultrasound diagnostic device 1 may use the B-mode data or B-mode image data obtained by the B-mode processing circuit 130 or the image generating circuit 150 based on the ultrasound signal 55 or the ultrasound signal 109 as teacher data. The ultrasound diagnostic device 1 may use the B-mode data or B-mode image data obtained by the B-mode processing circuit 130 or the image generating circuit 150 based on the ultrasound signal 65 as output data.

[0135] The program executed by the processor is provided in advance in a ROM (Read Only Memory) or a storage circuit. The program may be provided in a format that can be installed in these devices or in a format that can be executed, recorded on a non-transient computer-readable recording medium such as a CD (Compact Disk)-ROM, a FD (Flexible Disk), a CD-R (Recordable), or a DVD (Digital Versatile Disk). The program may be provided or distributed by being stored on a computer connected to a network such as the Internet and downloaded via the network. For example, the program is composed of modules including each of the above-mentioned processing functions. As actual hardware, a CPU reads out and executes the program from a recording medium such as a ROM, and each module is loaded onto a main storage device and generated on the main storage device.

[0136] According to at least one of the embodiments and at least one of the modified examples described above, it is possible to obtain harmonics with high accuracy while suppressing a decrease in frame rate.

[0137] Although some embodiments have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope of the invention and its equivalents as described in the claims, as well as in the scope and spirit of the invention. [Explanation of symbols]

[0138] 1. Ultrasound diagnostic equipment 101 Ultrasound probe 112 Receiving circuit 170a Pre-trained model

Claims

1. An ultrasonic probe, Based on the received signal representing the reflected wave from the subject received by the ultrasonic probe, the collection unit collects an ultrasonic signal in which one harmonic component of an odd or even order is emphasized more than the harmonic component of the other order. The system includes an acquisition unit that, based on the ultrasonic signal acquired by the acquisition unit, acquires a harmonic signal in which harmonic components of a predetermined multiple of the ultrasonic signal are emphasized more than other harmonic components. Ultrasound diagnostic equipment.

2. The acquisition unit performs a weighted summing process on the ultrasonic signal by applying a coefficient distribution in two or more different directions, thereby acquiring an ultrasonic signal as the harmonic signal that includes frequency components such that, at a specific frequency, the ratio of each order component included in the ultrasonic signal is different from that ratio. The ultrasound diagnostic apparatus according to claim 1.

3. The collection unit causes a plurality of ultrasonic waves having a first phase difference to be transmitted from the ultrasonic probe to the subject, and collects an ultrasonic signal in which the harmonic component of one order is emphasized more than the harmonic component of the other order by synthesizing the received signals representing the reflected waves from the subject received by the ultrasonic probe. The ultrasound diagnostic apparatus according to claim 1.

4. The acquisition unit causes two ultrasonic waves having a phase difference of 180 degrees to be transmitted from the ultrasonic probe to the subject, and by subtracting the received signal based on the reflected wave from the subject received by the ultrasonic probe, the acquisition unit acquires an ultrasonic signal in which odd-order harmonic components are emphasized more than even-order harmonic components as a first ultrasonic signal. The acquisition unit acquires a second ultrasonic signal based on the first ultrasonic signal, in which harmonic components of an order that is a multiple of 3 are emphasized more than harmonic components of other orders. The ultrasound diagnostic apparatus according to claim 3.

5. The second ultrasonic signal is a signal corresponding to an ultrasonic signal in which harmonic components of a multiple of third order are emphasized, obtained by transmitting three ultrasonic waves having a phase difference of 120 degrees from the ultrasonic probe to the subject, and adding the received signals based on the reflected waves from the subject received by the ultrasonic probe. The ultrasound diagnostic apparatus according to claim 4.

6. The acquisition unit causes two ultrasonic waves having a phase difference of 180 degrees to be transmitted from the ultrasonic probe to the subject, and by adding the received signals based on the reflected waves from the subject received by the ultrasonic probe, the acquisition unit acquires an ultrasonic signal in which even-order harmonic components are emphasized more than odd-order harmonic components as a first ultrasonic signal. The acquisition unit acquires a second ultrasonic signal based on the first ultrasonic signal, in which harmonic components of an order that is a multiple of 4 are emphasized more than harmonic components of other orders. The ultrasound diagnostic apparatus according to claim 3.

7. The second ultrasonic signal is a signal that corresponds to an ultrasonic signal in which harmonic components of a multiple of 4 are emphasized, obtained by transmitting four ultrasonic waves having a phase difference of 90 degrees from the ultrasonic probe to the subject, and adding the received signals based on the reflected waves from the subject received by the ultrasonic probe. The ultrasound diagnostic apparatus according to claim 6.

8. The acquisition unit acquires the ultrasonic signal using a trained model that has been trained to output a harmonic signal in which harmonic components of an order that is a multiple of 3 are emphasized more than harmonic components of an order other than the odd-order harmonic components, based on the input of an ultrasonic signal in which odd-order harmonic components are emphasized more than even-order harmonic components. The ultrasound diagnostic apparatus according to claim 2.

9. The acquisition unit acquires the ultrasonic signal using a trained model that has been trained to output a harmonic signal in which harmonic components of an order that is a multiple of 4 are emphasized more than harmonic components of an order other than the even-order harmonic components, based on the input of an ultrasonic signal in which even-order harmonic components are emphasized more than odd-order harmonic components. The ultrasound diagnostic apparatus according to claim 2.

10. A collection step of collecting an ultrasonic signal in which, based on a received signal representing a reflected wave from a subject received by an ultrasonic probe, one harmonic component of an odd order and the other of an even order is amplified more than the other harmonic component, The acquisition step includes acquiring a harmonic signal in which harmonic components of a predetermined multiple order of the ultrasonic signal are emphasized more than other harmonic components, based on the ultrasonic signal acquired in the acquisition step. Harmonic signal acquisition method.

11. A computer, An ultrasonic acquisition unit that collects an ultrasonic signal based on a received signal derived from a reflected wave from a subject received by an ultrasonic probe, in which one harmonic component of an odd or even order is amplified more than the other harmonic component of an even order. Based on the ultrasonic signal collected by the aforementioned acquisition unit, the acquisition unit is configured to acquire a harmonic signal in which harmonic components of a predetermined multiple order of the ultrasonic signal are emphasized more than other harmonic components. program.

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