Ultrasonic diagnostic device, method, and program

Abstract

To perform measurement on a condition suitable for a measurement object.SOLUTION: An ultrasonic diagnostic device 10 includes an analysis function 421, a setting function 412, and an acquisition function 411. The analysis function 421 analyzes a shearing wave propagated from a subject. On the basis of an analysis result for the shearing wave, the setting function 412 sets an acquisition condition for scan data. The acquisition function 411 performs scanning for the subject on the basis of the acquisition condition, and acquires scan data on the subject. Thereby, the acquisition condition for the scan data can be set on the basis of the analysis result for the shearing wave propagated from the subject so that measurement can be performed on a condition suitable for a measurement object.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The embodiments disclosed in this specification and the like relate to an ultrasonic diagnostic apparatus, method, and program.

Background Art

[0002] In recent years, in ultrasonic diagnostic apparatuses, shear wave elastography (SWE) that displays a hardness image by measuring the propagation speed of a shear wave generated by a push pulse has been used. SWE is, for example, one of the useful techniques for non-invasively and quantitatively evaluating the hardness of tissues in diffuse liver diseases.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0004] One of the problems to be solved by the embodiments disclosed in this specification and the like is to perform measurement under conditions suitable for the measurement target. However, the problems solved by the embodiments disclosed in this specification and the like are not limited to the above problems. The problems corresponding to the respective effects by the respective configurations shown in the embodiments described later can also be positioned as other problems solved by the embodiments disclosed in this specification and the like.

Means for Solving the Problems

[0005] The ultrasonic diagnostic apparatus according to the embodiment includes an analysis unit, a setting unit, and an acquisition unit. The analysis unit analyzes shear waves that have propagated through the subject. The setting unit sets the acquisition conditions for scan data based on the analysis result of the shear waves. The acquisition unit executes a scan on the subject based on the acquisition conditions and acquires the scan data of the subject.

Brief Description of the Drawings

[0006]

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[0007] Hereinafter, embodiments of the ultrasonic diagnostic apparatus, method, and program according to the present application will be described in detail with reference to the accompanying drawings. Note that the ultrasonic diagnostic apparatus, method, and program according to the present application are not limited to the embodiments shown below.

[0008] (First Embodiment) FIG. 1 is a block diagram showing an example of the configuration of an ultrasonic diagnostic apparatus 10 according to the first embodiment. As shown in FIG. 1, the ultrasonic diagnostic apparatus 10 according to the present embodiment includes an ultrasonic probe 1, a display 2, an input interface 3, and a device main body 4, and the ultrasonic probe 1, the display 2, and the input interface 3 are communicably connected to the device main body 4.

[0009] The ultrasonic probe 1 has a plurality of piezoelectric vibrators, and these plurality of piezoelectric vibrators generate ultrasonic waves based on a drive signal supplied from a transmission / reception circuit 41. Further, the ultrasonic probe 1 receives a reflected wave from a subject and converts it into an electrical signal. Further, the ultrasonic probe 1 has a matching layer provided on the piezoelectric vibrator, a backing material for preventing the propagation of ultrasonic waves rearward from the piezoelectric vibrator, and the like. Note that the ultrasonic probe 1 is detachably connected to the device main body 4.

[0010] When ultrasonic waves are transmitted from the ultrasonic probe 1 to the subject, the transmitted ultrasonic waves are successively reflected at the discontinuous surfaces of the acoustic impedance in the body tissues of the subject, and are received by a plurality of piezoelectric vibrators included in the ultrasonic probe 1 as reflected wave signals. The amplitude of the received reflected wave signal depends on the difference in acoustic impedance at the discontinuous surface where the ultrasonic wave is reflected. In addition, when the transmitted ultrasonic pulse is reflected at the surface of a moving blood flow, a heart wall, or the like, the reflected wave signal undergoes a frequency shift depending on the velocity component of the moving object with respect to the ultrasonic transmission direction due to the Doppler effect.

[0011] The ultrasonic probe 1 may be a one-dimensional ultrasonic probe in which a plurality of piezoelectric vibrators are arranged in a row, or may be an ultrasonic probe that mechanically oscillates the plurality of piezoelectric vibrators of the one-dimensional ultrasonic probe, or a two-dimensional ultrasonic probe in which a plurality of piezoelectric vibrators are arranged two-dimensionally in a lattice.

[0012] The display 2 displays a GUI (Graphical User Interface) for an operator of the ultrasonic diagnostic apparatus 10 to input various setting requests using the input interface 3, and ultrasonic images and the like generated in the apparatus main body 4. In addition, the display 2 displays various messages and display information in order to notify the operator of the processing status and processing results of the apparatus main body 4. Further, the display 2 has a speaker and can also output sound.

[0013] The input interface 3 is operated to set a predetermined position (e.g., the position of an ROI (Region Of Interest), etc.). For example, it is realized by a trackball, a switch button, a mouse, a keyboard, a touch pad that performs an input operation by touching an operation surface, a touch monitor in which a display screen and a touch pad are integrated, a non-contact input circuit using an optical sensor, and an audio input circuit, etc. The input interface 3 is connected to a processing circuit 45 described later, and converts an input operation received from an operator into an electrical signal and outputs it to the processing circuit 45. Note that in this specification, the input interface 3 is not limited to those equipped with physical operation components such as a mouse and a keyboard. For example, an electrical signal processing circuit that receives an electrical signal corresponding to an input operation from an external input device provided separately from the apparatus and outputs this electrical signal to the processing circuit 45 is also included in the examples of the input interface.

[0014] The apparatus main body 4 is an apparatus that generates an ultrasonic image based on the reflected wave signal received by the ultrasonic probe 1. As shown in FIG. 1, it has a transmission / reception circuit 41, a signal processing circuit 42, an image memory 43, a storage circuit 44, and a processing circuit 45. The transmission / reception circuit 41, the signal processing circuit 42, the image memory 43, the storage circuit 44, and the processing circuit 45 are connected so as to be mutually notifiable. In the ultrasonic diagnostic apparatus 10 shown in FIG. 1, each processing function is stored in the storage circuit 44 in the form of a program executable by a computer. The transmission / reception circuit 41, the signal processing circuit 42, and the processing circuit 45 are processors that realize the functions corresponding to the respective programs by reading and executing the programs from the storage circuit 44. In other words, each circuit in the state of having read each program has the function corresponding to the read program.

[0015] The transmission / reception circuit 41 includes a pulse generator, a transmission delay unit, a pulsar, etc., and supplies a drive signal to the ultrasonic probe 1. The pulse generator repeatedly generates rate pulses for forming transmission ultrasonic waves at a predetermined rate frequency. The transmission delay unit focuses the ultrasonic waves generated from the ultrasonic probe 1 into a beam shape, and gives the delay time for each piezoelectric vibrator necessary for determining the transmission directivity to each rate pulse generated by the pulse generator. The pulsar applies a drive signal (drive pulse) to the ultrasonic probe 1 at a timing based on the rate pulse. That is, the transmission delay unit arbitrarily adjusts the transmission direction of the ultrasonic waves transmitted from the piezoelectric vibrator surface by changing the delay time given to each rate pulse.

[0016] Note that the transmission / reception circuit 41 has a function capable of instantaneously changing the transmission frequency, the transmission drive voltage, etc. in order to execute a predetermined scan sequence based on an instruction from a processing circuit 45 described later. In particular, the change of the transmission drive voltage is realized by a linear amplifier type transmission circuit capable of instantaneously switching its value, or a mechanism for electrically switching a plurality of power supply units.

[0017] Also, the transmission / reception circuit 41 includes a preamplifier, an A / D (Analog / Digital) converter, a reception delay unit, an adder, etc., and performs various processes on the reflected wave signal received by the ultrasonic probe 1 to generate reflected wave data. The preamplifier amplifies the reflected wave signal for each channel. The A / D converter performs A / D conversion on the amplified reflected wave signal. The reception delay unit gives the delay time necessary for determining the reception directivity. The adder performs an addition process on the reflected wave signal processed by the reception delay unit to generate reflected wave data. By the addition process of the adder, the reflection component from the direction corresponding to the reception directivity of the reflected wave signal is emphasized, and a comprehensive beam of ultrasonic wave transmission / reception is formed by the reception directivity and the transmission directivity.

[0018] Here, as shown in FIG. 1, the transmission / reception circuit 41 executes an acquisition function 411 and a setting function 412. The acquisition function 411 transmits and receives ultrasonic waves for observing shear waves in the subject to acquire scan data. Also, the acquisition function 411 acquires the biological signal of the subject before acquiring the scan data. The setting function 412 sets the acquisition conditions of the scan data based on an index. Note that the processing by the acquisition function 411 and the setting function 412 will be described in detail later. Also, the acquisition function 411 is an example of a first acquisition unit and a second acquisition unit. Also, the setting function 412 is an example of a setting unit.

[0019] The signal processing circuit 42 performs, for example, logarithmic amplification, envelope detection processing, etc. on the reflected wave data received from the transmission / reception circuit 41 to generate data (B-mode data) in which the signal intensity for each sample point is expressed by the brightness of the luminance. The B-mode data generated by the signal processing circuit 42 is output to the processing circuit 45.

[0020] Also, the signal processing circuit 42 generates, for example, data (Doppler data) in which motion information based on the Doppler effect of the moving object is extracted at each sample point in the scanning region from the reflected wave data received from the transmission / reception circuit 41. Specifically, the signal processing circuit 42 performs frequency analysis on the velocity information from the reflected wave data, extracts blood flow, tissue, and contrast agent echo components due to the Doppler effect, and generates data (Doppler data) in which moving object information such as average velocity, variance, and power is extracted at multiple points. Here, the moving object is, for example, blood flow, tissue such as the heart wall, or a contrast agent. The motion information (blood flow information) obtained by the signal processing circuit 42 is sent to the processing circuit 45 and is color-displayed on the display 2 as an average velocity image, a variance image, a power image, or a combined image of these.

[0021] Also, as shown in FIG. 1, the signal processing circuit 42 executes an analysis function 421. The analysis function 421 calculates an index for determining the acquisition conditions of the scan data based on the biological signal. Note that the processing by the analysis function 421 will be described in detail later. Also, the analysis function 421 is an example of an analysis unit.

[0022] The image memory 43 is a memory that stores the image data for display generated by the processing circuit 45. Also, the image memory 43 can store the data generated by the signal processing circuit 42. The B-mode data and Doppler data stored in the image memory 43 can be called by the operator after diagnosis, for example, and become ultrasonic images for display via the processing circuit 45.

[0023] The storage circuit 44 stores control programs for ultrasonic transmission / reception, image processing, and display processing, diagnostic information (such as patient ID, doctor's findings, etc.), diagnostic protocols, and various data such as various body marks. Also, the storage circuit 44 stores the processing results of the transmission / reception circuit 41, the signal processing circuit 42, and the processing circuit 45. Further, the storage circuit 44 is also used for storing the image data stored in the image memory 43 as needed. Also, the data stored in the storage circuit 44 can be transferred to an external device via an interface (not shown). Note that the storage circuit 44 is an example of a storage unit.

[0024] The processing circuit 45 controls the overall processing of the ultrasonic diagnostic apparatus 10. Specifically, the processing circuit 45 controls the processing of the transmission / reception circuit 41 and the signal processing circuit 42 based on various setting requests input from the operator via the input interface 3, and various control programs and various data read from the storage circuit 44. Also, the processing circuit 45 controls the ultrasonic image for display stored in the image memory 43 to be displayed on the display 2.

[0025] As shown in FIG. 1, the processing circuit 45 executes a control function 451 and an image processing function 452. Here, the control function 451 is an example of a display control unit.

[0026] The control function 451 controls the processing of the transmission / reception circuit 41 and the signal processing circuit 42 based on various setting requests input from the operator via the input interface 3, as well as various control programs and various data read from the memory circuit 44. Further, the control function 451 controls to display an ultrasonic image and various information on the display 2. For example, the control function 451 controls to display an indicator on the display unit.

[0027] The image processing function 452 generates an ultrasonic image from the data generated by the signal processing circuit 42. That is, the image processing function 452 generates an ultrasonic image representing the intensity of the reflected wave as luminance from the B-mode data generated by the signal processing circuit 42. Further, the image processing function 452 generates an ultrasonic image representing moving body information (blood flow information or tissue movement information) from the Doppler data generated by the signal processing circuit 42. The ultrasonic image based on the Doppler data is velocity image data, dispersion image data, power image data, or image data combining these.

[0028] Here, the image processing function 452 generally converts (scan-converts) the scan line signal sequence of the ultrasonic scan into a scan line signal sequence in a video format typified by a television or the like, and generates a display ultrasonic image. Specifically, the image processing function 452 generates a display ultrasonic image by performing coordinate conversion according to the scanning form of the ultrasonic wave by the ultrasonic probe 1. Further, as various image processing other than scan conversion, the image processing function 452 performs, for example, image processing (smoothing processing) for regenerating an average value image of luminance using a plurality of image frames after scan conversion, image processing (edge enhancement processing) using a differential filter in the image, and the like. Further, the image processing function 452 synthesizes character information of various parameters, scales, body marks, etc. on the ultrasonic image.

[0029] That is, the B-mode data and Doppler data are ultrasonic image data before scan conversion processing, and the data generated by the image processing function 452 is ultrasonic image data for display after scan conversion processing. Note that when the signal processing circuit 42 generates three-dimensional data (three-dimensional B-mode data and three-dimensional Doppler data), the image processing function 452 performs coordinate conversion according to the ultrasonic scanning pattern by the ultrasonic probe 1 to generate volume data. Then, the image processing function 452 performs various rendering processes on the volume data to generate two-dimensional image data for display.

[0030] Here, the ultrasonic diagnostic apparatus 10 according to the first embodiment is an apparatus capable of performing elastography for measuring the hardness (such as elastic modulus) of a living tissue and visualizing the distribution of the measured hardness. Specifically, the ultrasonic diagnostic apparatus 10 according to the first embodiment is an apparatus capable of performing shear wave elastography (SWE) by applying an acoustic radiation force to generate displacement in the living tissue.

[0031] Currently, in SWE, since the hardness of the tissue to be measured is measured under a single condition, there are cases where shear waves cannot be appropriately observed depending on the state of the tissue to be measured. FIGS. 2A and 2B are diagrams for explaining the propagation of shear waves in SWE. Note that FIG. 2A is a diagram for explaining the propagation of shear waves for each elapsed time within the space where a push pulse is transmitted. FIG. 2B is a diagram for explaining the propagation of shear waves for each tracking pulse within the measurement region where the hardness is measured.

[0032] As shown in FIG. 2A, when a push pulse is transmitted to a biological tissue, a shear wave that propagates in the Lateral direction is generated. Here, in the current SWE, since the shear wave is observed under a single acquisition condition, the shear wave may not fit within the measurement region depending on the hardness of the tissue in the measurement region. That is, when the tissue to be measured is hard, as shown by the dotted line waveform in the figure, the propagation speed of the shear wave is fast, and the shear wave may not be properly captured by the tracking pulse. Also, when the tissue to be measured is soft, as shown by the dashed-dotted line waveform in the figure, the propagation speed of the shear wave is slow, and the shear wave may not be properly captured by the tracking pulse. Note that for the shear wave shown by the broken line waveform, it can be properly observed.

[0033] Also, as shown in FIG. 2B, in the current SWE, there may be a case where the shear wave does not fit within the measurement region during the measurement time from the start to the end of measurement in the measurement region. That is, when the tissue to be measured is hard, since the propagation speed of the shear wave is fast, as shown by the dotted line waveform in the figure, the timing of the start of measurement is not in time, and the shear wave may not be properly captured. Also, when the tissue to be measured is soft, since the propagation speed of the shear wave is slow, as shown by the dashed-dotted line waveform in the figure, the propagation of the shear wave does not reach the timing of the end of measurement in time, and the shear wave may not be properly captured. Note that for the shear wave shown by the broken line waveform, it can be properly observed.

[0034] Thus, in the SWE measurement, the optimal transmission and reception conditions differ depending on the hardness of the measurement tissue for the push pulse for generating the shear wave and the tracking pulse for observing the shear wave. Therefore, the ultrasonic diagnostic apparatus 10 according to the first embodiment calculates rough information regarding hardness by performing a pre-scan on the measurement target, and by setting the acquisition conditions based on the calculated information, enables measurement under conditions suitable for the measurement target.

[0035] The procedure of the processing by the ultrasonic diagnostic apparatus 10 will be described with reference to FIG. 3, and then the details of each process will be described. FIG. 3 is a flowchart showing the procedure of the processing of the ultrasonic diagnostic apparatus according to the first embodiment.

[0036] For example, as shown in FIG. 3, in the present embodiment, the acquisition function 411 executes a pre-scan (pre-SWE) on the subject (step S101). Specifically, the acquisition function 411 transmits push pulses and transmits and receives tracking pulses, thereby acquiring scan data (biological signals of the subject) regarding the shear wave propagated through the subject. The process of step S101 is realized, for example, by the transmission / reception circuit 41 calling a program corresponding to the acquisition function 411 from the storage circuit 44 and executing it.

[0037] Subsequently, the analysis function 421 analyzes the shear wave propagated through the subject based on the scan data acquired by the acquisition function 411 (step S102). The analysis function 421 analyzes the shear wave (first shear wave) propagated through each position of the measurement region (first measurement region R1) of the subject targeted by the pre-SWE. The analysis function 421 acquires, as the analysis result of the shear wave, a tissue property index value indicating the tissue property of the subject at each position in the first measurement region R1. Then, the analysis function 421 determines whether the analysis result is appropriate (step S103). The processes of steps S102 and S103 are realized, for example, by the signal processing circuit 42 calling a program corresponding to the analysis function 421 from the storage circuit 44 and executing it.

[0038] In the determination of step S103, when the analysis result is not appropriate (step S103, No), the control function 451 causes the warning information to be displayed on the display 2 (step S104), and controls to execute the pre-scan again. The process of step S104 is realized, for example, by the processing circuit 45 calling a program corresponding to the control function 451 from the storage circuit 44 and executing it.

[0039] On the other hand, in the determination of step S103, when the analysis result is appropriate (step S103, Yes), the setting function 412 sets the acquisition conditions for the scan data of SWE based on the analysis result of the shear wave (step S105). Specifically, the setting function 412 sets, as the acquisition conditions for the scan data, the transmission conditions of the push pulse for generating the second shear wave in the subject and the transmission / reception conditions of the tracking pulse for observing the second shear wave, based on the analysis result of the first shear wave. The setting function 412 sets the acquisition conditions for the scan data based on the tissue property index values at each position in the first measurement region R1. The process of step S105 is realized, for example, by the transmission / reception circuit 41 calling and executing a program corresponding to the setting function 412 from the storage circuit 44.

[0040] Subsequently, the acquisition function 411 executes this scan (this SWE) using the set acquisition conditions (step S106). That is, the acquisition function 411 executes this scan on the subject based on the acquisition conditions set by the setting function 412 and acquires the scan data of the subject. The process of step S106 is realized, for example, by the transmission / reception circuit 41 calling and executing a program corresponding to the acquisition function 411 from the storage circuit 44.

[0041] Subsequently, the control function 451 controls to display on the display 2 the evaluation information (the hardness of the tissue to be measured) based on the scan data (step S107). That is, the control function 451 displays, as the evaluation information, the ultrasonic image (SWE image) based on the scan data of the subject acquired by the acquisition function 411. The process of step S106 is realized, for example, by the processing circuit 45 calling and executing a program corresponding to the control function 451 from the storage circuit 44.

[0042] Hereinafter, the details of each process executed by the ultrasonic diagnostic apparatus 10 will be described.

[0043] (Pre-scan) As described in step S101, the acquisition function 411 performs a pre-scan (pre-SWE) including transmission of push pulses and transmission and reception of tracking pulses. The push pulse is a focused ultrasonic pulse that generates a shear wave, which is a transverse wave, in a biological tissue (subject) based on acoustic radiation force, and is an example of ultrasonic waves for generating a shear wave. The tracking pulse is an ultrasonic pulse for observing the shear wave, and is an example of ultrasonic waves for observing the shear wave.

[0044] For example, the acquisition function 411 causes the ultrasonic probe 1 to transmit a push pulse to generate a first shear wave in the biological tissue. Then, the acquisition function 411 causes the ultrasonic probe 1 to transmit a tracking pulse for observing the first shear wave generated based on the push pulse. The tracking pulse is transmitted to observe the propagation speed of the first shear wave generated by the push pulse at each sample point in the first measurement region R1. Usually, the tracking pulse is transmitted a plurality of times (for example, 100 times) for each scan line in the first measurement region R1. The acquisition function 411 generates reflected wave data (scan data) from the reflected wave signals of the tracking pulses transmitted on each scan line in the first measurement region R1.

[0045] Here, the acquisition function 411 performs transmission of push pulses and transmission and reception of tracking pulses under acquisition conditions that enable acquisition of each shear wave propagating through tissues with different tissue properties in the pre-scan. That is, the acquisition function 411 performs the pre-scan under transmission conditions of push pulses and transmission and reception conditions of tracking pulses that can capture shear waves even in various tissue properties (tissues with various hardnesses). The acquisition conditions for the pre-scan (acquisition conditions for scan data) are preset and stored in the storage circuit 44, and are read out by the acquisition function 411 during the pre-scan.

[0046] (Analysis process) As described in step S102, the analysis function 421 analyzes the shear wave (first shear wave) acquired by the pre-scan (pre-SWE) of the acquisition function 411, and calculates the degree of tissue hardness (elastic modulus) in the first measurement region R1. Specifically, the analysis function 421 analyzes the shear wave (first shear wave) propagated through each position in the measurement region (first measurement region R1) of the subject targeted by the pre-SWE. The analysis function 421 acquires, as the analysis result of the first shear wave, a tissue property index value indicating the tissue property of the subject at each position in the first measurement region R1. The tissue property index value has, for example, at least one of an elastic index value indicating the elasticity of the subject's tissue and a viscosity index value indicating the viscosity of the subject's tissue. The elastic index value (elastic value) includes, for example, the shear wave propagation speed, the shear wave arrival time, the shear modulus, the Young's modulus, etc. The viscosity index value (viscosity value) includes a viscosity coefficient obtained by a Voigt model or a Maxwell model with respect to the relationship between the frequency component and the propagation speed (phase speed), a dispersion value (Dispersion Slope value) of the propagation speed with respect to the frequency component, etc. Further, the analysis function 421 may calculate a statistical value (average value, median value, dispersion value, standard deviation value, range of the tissue property index value, etc.) of the tissue property index value at each position in the first measurement region R1 as an approximate tissue property index value in the first measurement region R1, and use this as the analysis result of the first shear wave.

[0047] For example, the analysis function 421 analyzes the reflected wave data of the tracking pulses transmitted a plurality of times on each scan line in the first measurement region R1 in the pre-scan, and calculates hardness distribution data (elastic index value at each position in the first measurement region R1) indicating the hardness distribution in the first measurement region R1. As an example, the analysis function 421 measures the propagation speed of the first shear wave generated by the push pulse at each sample point in the first measurement region R1, and may calculate a statistical value (average value, median value, dispersion value, standard deviation value, range of the propagation speed) of the propagation speed (elastic index value) at each sample point as the analysis result of the first shear wave.

[0048] For example, the analysis function 421 generates motion information (tissue Doppler data) at each of a plurality of sample points on each scan line over a plurality of time phases by performing frequency analysis on the reflected wave data of the tracking pulse. Then, the analysis function 421 time-integrates the velocity components of the tissue Doppler data of a plurality of time phases obtained at each of the plurality of sample points on each scan line. Thereby, the analysis function 421 calculates the displacements of each of the plurality of sample points on each scan line over a plurality of time phases. That is, the displacement is detected as a displacement waveform (time displacement curve). That is, the analysis function 421 analyzes the scan data collected by transmitting the push pulse and transmitting and receiving the tracking pulse, and detects the movement (displacement) of the tissue at each of a plurality of positions in the subject. Further, the displacement waveform is an example of waveform information representing a shear wave.

[0049] Subsequently, the analysis function 421 obtains the time at which the displacement becomes maximum at each sample point in the first measurement region R1. Then, the analysis function 421 determines the time at which the maximum displacement is obtained at each sample point as the arrival time at which the shear wave reaches each sample point. Subsequently, the analysis function 421 calculates the propagation speed of the first shear wave at each sample point by performing a spatial differentiation of the arrival times of the shear waves at each sample point. Note that the arrival time of the first shear wave is not limited to only the time at which the displacement becomes maximum at each sample point. For example, the time at which the change amount of the displacement at each sample point becomes maximum may be used.

[0050] Then, the analysis function 421 calculates an approximate elastic value (for example, a statistical value of an elasticity index value) within the first measurement region R1 from the information on the propagation speed of the first shear wave at each sample point in the first measurement region R1. The propagation speed of the shear wave is fast in hard tissues and slow in soft tissues. That is, the value of the propagation speed of the shear wave becomes a value (elasticity index value) indicating the hardness of the tissue. In the above case, the tracking pulse is a transmission pulse for tissue Doppler. Note that the above-described propagation speed of the shear wave can also be calculated by the cross-correlation of the displacements of the tissues in adjacent scan lines.

[0051] Note that the analysis function 421 may calculate the elastic modulus (Young's modulus, shear modulus) from the propagation speed of the first shear wave. The propagation speed of the shear wave, Young's modulus, and shear modulus can all be used as physical quantities (elastic index values) representing the hardness of the biological tissue. Note that hardness is an example of a parameter representing tissue properties (elasticity).

[0052] Note that instead of calculating an approximate elastic value (for example, a statistical value of the elastic index value) within the first measurement region R1 based on the propagation speed of the first shear wave, the analysis function 421 may calculate an approximate elastic value within the first measurement region R1 based on the waveform information of the first shear wave. Hereinafter, each calculation example will be described.

[0053] First, an example of calculating an approximate elastic value within the first measurement region R1 based on the propagation speed of the first shear wave will be described. FIGS. 4A and 4B are diagrams for explaining an example of processing by the analysis function 421 according to the first embodiment. Note that FIGS. 4A and 4B show an example of calculating a statistical value of the elastic index value within the first measurement region R1 based on the propagation speed of the first shear wave obtained at each position in the first measurement region R1 by executing a pre-scan.

[0054] For example, as shown in FIG. 4A, the analysis function 421 analyzes the reflected wave data of the tracking pulses transmitted a plurality of times on each scanning line within the first measurement region R1 (the rectangle in the figure) in the pre-scan, and calculates the propagation speed for each position within the first measurement region R1 for the first shear wave generated by the push pulse. For example, as shown in FIG. 4A, the analysis function 421 calculates the propagation speeds of "1.2 m / s", "1.8 m / s", and "1.4 m / s" between adjacent scanning lines. Then, the analysis function 421 calculates a range of the propagation speed of the first shear wave within the first measurement region R1, "speed range: 1.2 - 1.8 m / s", from the calculated propagation speeds. That is, in this case, "speed range: 1.2 - 1.8 m / s" is obtained as an approximate elastic value (statistical value of the propagation speed) within the first measurement region R1 shown in FIG. 4A.

[0055] In addition, the analysis function 421 can analyze the propagation speed of the first shear wave not only between the adjacent scanning lines described above but also at other positions. For example, as shown in FIG. 4B, the analysis function 421 calculates the propagation speeds of the first shear wave between non-adjacent scanning lines, namely "1.7 m / s" and "1.9 m / s", in addition to the propagation speeds of the first shear wave between adjacent scanning lines, namely "1.2 m / s", "1.8 m / s", and "1.4 m / s", and calculates the "speed range: 1.2 - 1.9 m / s" within the first measurement region R1 from the calculated propagation speeds. That is, in this case, the "speed range: 1.2 - 1.9 m / s" is obtained as an approximate elastic value (statistical value of the tissue property index value) within the first measurement region R1 shown in FIG. 4B.

[0056] Note that the above example is merely an example, and the embodiment is not limited thereto. For example, the number of propagation speeds calculated by the analysis function 421 is not limited to that shown in the figure. In the above example, as an example of an approximate elastic value (statistical value of the elastic index value) within the first measurement region R1, the case of calculating the range of elastic values within the first measurement region R1 has been described. However, the analysis function 421 may calculate statistical values such as the average value, median value, variance value, and standard deviation value of the elastic values as approximate elastic values within the first measurement region R1. For example, as shown in FIG. 4A or FIG. 4B, the analysis function 421 may calculate the average value or median value of the propagation speed of the first shear wave at each position in the first measurement region R1 and obtain this as an approximate elastic value within the first measurement region R1.

[0057] In addition, the analysis function 421 may calculate the variance value of the elastic value and adjust the average value, median value, and range of the elastic value. For example, the analysis function 421 calculates the variance value of the propagation speed of the first shear wave, and when the calculated variance value exceeds a threshold value, it adjusts the average value, median value, and range of the propagation speed of the first shear wave, and obtains the elastic value corresponding to the adjusted speed. Taking an example, when the calculated variance value exceeds the threshold value, the analysis function 421 increases the average value and median value of the propagation speed of the first shear wave and increases the upper limit value of the range. That is, when the variance value is high, the analysis function 421 changes the conditions so that the tissue within the first measurement region R1 includes a harder tissue.

[0058] Next, an example of calculating an approximate elastic value within the first measurement region R1 based on the waveform information of the first shear wave will be described. FIGS. 5A, 5B, and 5C are diagrams for explaining an example of the processing by the analysis function 421 according to the first embodiment. Note that FIGS. 5A, 5B, and 5C show an example of calculating a statistical value of the elastic index value within the first measurement region R1 based on the waveform information of the shear wave at each position in the first measurement region R1 by executing a pre-scan.

[0059] For example, as shown in FIG. 5A, the analysis function 421 determines, based on the waveform information of the first shear wave, whether the arrival time of the first shear wave falls within the measurement time during the pre-scan, and calculates the range of the elastic value of the tissue within the first measurement region R1 (the statistical value of the elastic index value) based on the determination result.

[0060] Also, for example, as shown in FIG. 5B, the analysis function 421 calculates the elastic value from the amplitude and wavelength of the shear wave. For example, as shown in FIG. 5B, when the shear wave has an amplitude of "1.2 μm" and a wavelength of "2.4 μs", the analysis function 421 calculates the propagation speed of "1.3 m / s" from "1.2 / 2.4 = 0.5" based on a function showing the relationship between the propagation speed "m / s" and "amplitude / wavelength". Then, the analysis function 421 obtains, for example, the hardness of "7 kPa" from the propagation speed of "1.3 m / s". Note that the analysis function 421 can calculate the average value, median value, and range (the statistical value of the elastic index value) of the elastic value within the first measurement region R1 by obtaining the above-described hardness for a plurality of positions within the first measurement region R1. The wavelength and amplitude of the first shear wave are such that in a soft tissue, the amplitude is high and the wavelength is long, and in a hard tissue, the amplitude is low and the wavelength is short. Therefore, a function showing the relationship between the propagation speed "m / s" and "amplitude / wavelength" is obtained in advance and stored, for example, in the storage circuit 44.

[0061] Further, for example, as shown in FIG. 5C, the analysis function 421 calculates an elastic value from the degree of coincidence between the waveform of the shear wave and the waveform patterns of each hardness pre-embedded. For example, as shown in FIG. 5C, the analysis function 421 calculates the cross-correlation between each waveform corresponding to a plurality of propagation speeds including "1.3 m / s" and "1.0 m / s" and the waveform of the shear wave acquired in the pre-scan, and determines from the calculated cross-correlation results that the waveform of the shear wave acquired in the pre-scan has a high degree of coincidence with the waveform of "1.3 m / s". Then, the analysis function 421 acquires, for example, the hardness of "7 kPa" from the propagation speed of "1.3 m / s". Note that the analysis function 421 can calculate the average value, median value, and range (statistical value of the elastic index value) of the elastic values in the first measurement region R1 by acquiring the above-described hardness for a plurality of positions in the first measurement region R1. Also, the waveform patterns corresponding to each propagation speed are acquired in advance and stored, for example, in the storage circuit 44.

[0062] (Determination Process of Analysis Result) As described in step S103, the analysis function 421 determines whether the analysis result of the first shear wave is appropriate. For example, the analysis function 421 determines that the analysis result is not appropriate when the calculated degree of the elastic value is an obvious abnormal value or when the variance value of the elastic value exceeds a predetermined threshold. Note that the reference value for determining an abnormal value and the predetermined threshold are set in advance. Also, the predetermined threshold for comparison with the variance value is set higher than the threshold for determining whether to adjust the above-described elastic value.

[0063] (Display of Warning Information) As described in step S104, when it is determined that the analysis result of the first shear wave is not appropriate, the control function 451 controls to display warning information. That is, when the index (analysis result of the first shear wave) does not meet the standard, the control function 451 controls to display warning information regarding the index. For example, the control function 451 controls to display on the display 2 warning information indicating that the analysis in the pre-scan was not properly performed. In addition to the above-described information, the control function 451 can also display information prompting a change in the position of the first measurement region R1.

[0064] In addition, the control function 451 can also display the index (analysis result of the first shear wave) on the display 2. For example, the control function 451 can display on the display 2 the elastic value (here, the statistical value of the elastic index value) within the first measurement region R1 calculated by the analysis function 421. Here, the control function 451 is not limited to the case of displaying warning information, and may also display the elastic value within the first measurement region R1 on the display 2 even when the analysis result is appropriate.

[0065] (Setting process for acquisition conditions) As described in step S105, when the analysis result is appropriate, the setting function 412 sets the acquisition conditions for the scan data of this scan. Specifically, the setting function 412 sets the acquisition conditions for this scan based on the approximate elastic value (here, the statistical value of the elastic index value within the first measurement region R1) calculated by the analysis function 421. That is, the setting function 412 sets, as the acquisition conditions for the scan data, the transmission conditions of the push pulse that generates a shear wave (second shear wave) in the subject and the transmission and reception conditions of the tracking pulse that observes the second shear wave propagated through the subject, based on the analysis result of the first shear wave. The setting function 412 according to the present embodiment can set the acquisition conditions by various methods. These examples will be described below.

[0066] For example, the setting function 412 selects the acquisition condition (acquisition condition for this scan) of the scan data from among a plurality of pre-set acquisition conditions based on an index (analysis result of the first shear wave). That is, the setting function 412 compares the approximate elastic value (analysis result of the first shear wave (here, the statistical value of the elastic index value)) calculated by the analysis function 421 with the plurality of pre-set acquisition conditions, and selects, from among the plurality of acquisition conditions, an acquisition condition appropriate for the tissue of the subject for which the pre-scan was performed.

[0067] FIG. 6 is a diagram for explaining an example of the processing by the setting function 412 according to the first embodiment. Here, in FIG. 6, the range of the elastic value (hardness) "0.75 kPa - 200 kPa" is divided into five pre-set ranges "0.75 kPa - 2 kPa", "2 kPa - 10 kPa", "10 kPa - 30 kPa", "30 kPa - 100 kPa", "100 kPa - 200 kPa", and the case where acquisition conditions corresponding to each are set is shown.

[0068] For example, as shown in FIG. 6, the setting function 412 selects, from among the five pre-set ranges, the range "10 kPa - 30 kPa" corresponding to the statistical value (average value, median value, range, etc.) of the elastic value within the first measurement region R1 measured in the pre-scan. Further, the setting function 412 may select, from among the five ranges, the range that most overlaps with the range of the elastic value within the first measurement region R1 measured in the pre-scan. Thereby, for example, the setting function 412 can set the acquisition condition for the range including the correct elastic value "15 kPa".

[0069] Note that, in FIG. 6, the case where five ranges are pre-set has been described, but the embodiment is not limited to this, and ranges can be set with any number and numerical range. Also, in FIG. 6, the case where the five pre-set ranges are set so as not to overlap between adjacent ranges has been described, but the embodiment is not limited to this, and a case where ranges with overlapping elastic values between adjacent ranges are set may also be possible.

[0070] As described above, the setting function 412 sets the acquisition conditions (scan data acquisition conditions) for the present scan based on the index (analysis result of the first shear wave) acquired by the pre-scan. Specifically, the setting function 412 sets, as the acquisition conditions for the scan data of the present scan, at least one of the transmission conditions of the push pulse for observing the second shear wave, the transmission and reception conditions of the tracking pulse for observing the second shear wave propagated through the second measurement region R2 of the subject to be examined in the present SWE, the conditions related to the display based on the scan data, and the conditions related to the analysis based on the scan data. For example, the setting function 412 sets, based on the analysis result of the first shear wave, a condition including at least one of the position and size of the second measurement region R2 as the acquisition condition for the scan data. Further, the setting function 412 sets, based on the analysis result of the first shear wave, a condition including at least any one of the measurement start time, the measurement end time, and the measurement time width of the second shear wave at each position of the second measurement region R2 as the acquisition condition for the scan data. For example, the acquisition conditions set by the setting function 412 include the following adjustment parameters.

[0071] The adjustment parameters related to the push pulse include "transmission intensity", "transmission times", "transmission position", "transmission waveform", "frame rate", etc. The adjustment parameters related to the tracking pulse include "distance from the push pulse", "lateral width (distance between scan lines)", "measurement start time", "measurement end time", "time width", "simultaneous reception number (number of reception beams)", etc. The adjustment parameters related to the color bar include at least "change of color range", etc. The adjustment parameters related to the tissue property analysis include at least "region where the Directional Filter is set to 0", etc.

[0072] In addition, the setting function 412 sets at least one of the time from the acquisition of the biological signal to the start of the acquisition of the scan data and the time from the acquisition of the scan data to the start of the acquisition of the next scan data based on an index (the analysis result of the first shear wave). That is, the setting function 412 sets the time from after the pre-scan to the start of this scan and / or the time between scans when performing a scan again after this scan based on the approximate elastic value of the first measurement region R1 calculated by the pre-scan. Hereinafter, the time from after the pre-scan to the start of this scan and the time to perform a scan again after the end of this scan may be described as the cool time.

[0073] Here, a specific example of setting the above parameters will be described. For example, as the tissue softens (the shear wave propagation speed decreases), each adjustment parameter is set as follows. For example, in the push pulse, the condition is set to "lower the transmission output" as the tissue softens. Also, for example, in the tracking pulse, the conditions are set to "increase the distance between beams (scanning lines)", "shorten the distance between the push pulse and the first beam", and "reduce the PRF (widen the time width)" as the tissue softens. In addition, as the tissue softens, the acquisition conditions for the scan data are set to "increase the frame rate of the push pulse in the multi-shot mode" and "shorten the cool time".

[0074] On one hand, as the hardness of the tissue increases (the propagation speed of the shear wave increases), each adjustment parameter is set as follows. For example, in the case of a push pulse, as the hardness increases, the condition is set to "increase the transmission output". Also, for example, in the case of a tracking pulse, as the hardness increases, the conditions are set to "reduce the distance between beams (scanning lines)", "increase the distance between the push pulse and the first beam", and "increase the PRF (make the time width finer)". Further, as the hardness decreases, the conditions are set to "reduce the frame rate of the push pulse in the multi-shot mode" and "increase the cool-down time".

[0075] For example, for the five ranges shown in FIG. 6, acquisition conditions in which the above-described parameters are set according to the hardness of each range are respectively associated, and the corresponding information is stored in the storage circuit 44. The setting function 412 reads out the corresponding information corresponding to the selected range from the storage circuit 44 and sets it as the acquisition condition for this scan.

[0076] Also, the setting function 412 may input, for example, the index (analysis result of the shear wave) analyzed by the analysis function 421 to a model that outputs the acquisition condition of the scan data in response to the input of the index (analysis result of the shear wave), and set the acquisition condition of the scan data output by the model. For example, the setting function 412 acquires the acquisition condition by inputting the analysis result of the analysis function 421 to a pre-constructed statistical regression model or machine learning model. Note that the statistical regression model and the machine learning model are stored in advance in the storage circuit 44, for example.

[0077] As an example, the setting function 412 calculates the adjustment parameter using the statistical regression models shown in the following formulas (1) and (2). Note that the following formula (1) is a formula for calculating the irradiation interval of the tracking pulse, and formula (2) is a formula for calculating the lateral width of the tracking pulse. Also, "A" and "B" in formula (1) and "C" in formula (2) indicate preset coefficients, and "v" in formulas (1) and (2) indicates the propagation speed of the shear wave.

[0078] (1) Tracking Width = A·v + B (2) Beam Width = C / v

[0079] That is, the setting function 412 calculates each adjustment parameter by substituting the value of the propagation speed calculated by the analysis function 421 into equations (1) and (2). Note that the above equations are merely examples, and the embodiments are not limited thereto. Also, in the above, only the models related to two adjustment parameters are shown, but models for calculating each adjustment parameter can be constructed respectively.

[0080] Also, when constructing a machine learning model, the machine learning model may be constructed so as to output acquisition conditions including all parameters according to the input of the analysis result. That is, a machine learning model learned using the analysis result (propagation speed or elastic value) by the analysis function 421 and the acquisition conditions including all parameters as learning data may be used.

[0081] As described above, the setting function 412 sets the acquisition conditions for the present scan based on the analysis result of the pre-scan. Further, the setting function 412 can set the number of scans and the acquisition interval for the present scan based on the analysis result of the pre-scan. Specifically, after a biological signal is acquired, when a plurality of scan data are continuously acquired, the setting function 412 sets the transmission conditions of the push pulse and the transmission and reception conditions of the tracking pulse for observing the shear wave based on an index. That is, the setting function 412 sets the frequency, interval, etc. of the push pulse and the tracking pulse based on the index.

[0082] (The present scan) As described in step S106, the acquisition function 411 executes this scan (this SWE) based on the set acquisition conditions. Specifically, the acquisition function 411 executes this scan including the transmission of push pulses and the transmission and reception of tracking pulses based on the acquisition conditions set by the setting function 412, and acquires scan data of the subject. For example, the acquisition function 411 causes a push pulse to be transmitted from the ultrasonic probe 1 to generate a second shear wave in the biological tissue. Then, the acquisition function 411 causes the ultrasonic probe 1 to transmit a tracking pulse for observing the second shear wave generated based on the push pulse. The tracking pulse is transmitted to observe the propagation speed of the second shear wave generated by the push pulse at each sample point in the second measurement region R2. The acquisition function 411 generates reflected wave data (scan data) from the reflected wave signals of the tracking pulses transmitted on each scan line in the second measurement region R2.

[0083] (Display process of evaluation information) As described in step S107, the control function 451 causes the display 2 to display evaluation information (for example, an SWE image) based on the scan data acquired by the acquisition function 411. For example, the control function 451 causes the display 2 to display a hardness image (SWE image) in which a color corresponding to the elastic value (propagation speed of the second shear wave) at each position in the second measurement region R2 is assigned to each position (for example, each pixel) in the second measurement region R2. In such a case, for example, the control function 451 generates information on the propagation speed of the second shear wave at each sample point in the second measurement region R2 as hardness distribution data based on the scan data acquired by this scan. Then, the image processing function 452 generates the above-described hardness image (SWE image) based on the hardness distribution data. In this embodiment, based on the analysis result of the first shear wave by the pre-scan, the color bar is also set to be suitable for the measurement target, so that a more easily observable hardness image can be displayed.

[0084] Hereinafter, an application example of this embodiment will be described with reference to FIGS. 7 and 8. FIG. 7 is a diagram for explaining the sequence of processing by the ultrasonic diagnostic apparatus 10 according to the first embodiment. Further, FIG. 8 is a diagram for explaining the processing by the ultrasonic diagnostic apparatus 10 according to the first embodiment. Note that FIG. 8 shows the processing in "PreSWE" and "this SWE" in FIG. 7. Note that "PreSWE" corresponds to the above-described pre-scan, and "this SWE" corresponds to the above-described this scan.

[0085] For example, as shown in FIG. 7, the ultrasonic diagnostic apparatus 10 first acquires and displays a B-mode image of a tissue to be measured of a subject by "B-mode Scan", and receives an operation for setting a measurement region (color ROI) for displaying a hardness image, and determines the color ROI. Note that the color ROI corresponds to a region R2 described later.

[0086] Subsequently, when the ultrasonic diagnostic apparatus 10 receives an instruction to start measurement, it starts "PreSWE". That is, the ultrasonic diagnostic apparatus 10 transmits a push pulse for "PreSWE" to generate a shear wave, and measures the shear wave by transmitting and receiving a tracking pulse for "PreSWE". Then, the ultrasonic diagnostic apparatus 10 analyzes the approximate hardness range of the tissue within the color ROI, and sets the transmission and reception conditions for "this SWE" based on the analysis result.

[0087] Thereafter, the ultrasonic diagnostic apparatus 10 transmits a push pulse for "this SWE" to generate a shear wave, measures the shear wave by transmitting and receiving a tracking pulse for "this SWE", and performs 2D display of the hardness image. Here, the ultrasonic diagnostic apparatus 10 automatically performs the process from the start of measurement of "PreSWE" to 2D display, and it is desirable to complete this within about 10 seconds of holding the breath.

[0088] In the above-mentioned "PreSWE", for example, the acquisition function 411 sets a region R1, which is an ROI for "PreSWE", near the center of the region R2 (color ROI) shown in FIG. 8. That is, the region R1 (first measurement region) is smaller than the region R2 (second measurement region). Then, the acquisition function 411 performs a pre-scan on the region R1, for example, with one push pulse or several track pulses, to acquire shear waves at a plurality of positions within the region R1. Here, the acquisition function 411 executes the pre-scan under acquisition conditions that can calculate an approximate elastic value within the region R1 from a wide range of hardness ranges, and under conditions such that the cool-down time has little time loss until "this SWE (this scan)".

[0089] The analysis function 421 calculates a hardness range of "10 kPa - 25 kPa" from the propagation speeds of the shear waves at a plurality of positions within the region R1 acquired by the pre-scan. The setting function 412 sets the acquisition conditions for "this SWE" from a comparison between the calculated hardness range and a plurality of pre-set ranges. The acquisition function 411 executes this scan on the region R2 according to the acquisition conditions set by the setting function 412. The control function 451 uses the result of this scan acquired by the acquisition function 411 to display a hardness image in which colors corresponding to the propagation speeds of the shear waves are assigned to each position within the region R2.

[0090] As described above, the ultrasonic diagnostic apparatus 10 according to the present embodiment can set the acquisition conditions for this scan based on the analysis result of the pre-scan, and can also save the set acquisition conditions. In such a case, for example, the storage circuit 44 stores the acquisition conditions for the scan data. The acquisition function 411 can read the acquisition conditions for the scan data from the storage circuit 44 and acquire the scan data based on the read acquisition conditions.

[0091] For example, in SWE, multiple main scans may be performed on the same subject. In that case, the acquisition conditions set in the first main scan are stored in the storage circuit 44 in association with the subject, and when performing the next main scan, the acquisition function 411 reads out the acquisition conditions and executes the main scan. Thereby, the inspection time can be shortened.

[0092] As described above, according to the first embodiment, the acquisition function 411 transmits and receives ultrasonic waves for observing shear waves in the subject to acquire scan data. The acquisition function 411 acquires the biological signal of the subject before acquiring the scan data. The analysis function 421 calculates an index for determining the acquisition conditions of the scan data based on the biological signal. The setting function 412 sets the acquisition conditions of the scan data based on the index. Therefore, the ultrasonic diagnostic apparatus 10 according to the first embodiment can set the acquisition conditions of the scan data based on the biological signal of the subject, and enables measurement to be performed under conditions suitable for the measurement target.

[0093] Also, according to the first embodiment, the acquisition function 411 acquires shear waves acquired by transmitting a push pulse and transmitting and receiving a tracking pulse as the biological signal. Therefore, the ultrasonic diagnostic apparatus 10 according to the first embodiment can perform SWE under acquisition conditions suitable for the tissue to be measured.

[0094] Also, according to the first embodiment, the acquisition function 411 executes transmission of a push pulse and transmission and reception of a tracking pulse under acquisition conditions capable of acquiring each shear wave propagating through tissues with different tissue properties. Therefore, the ultrasonic diagnostic apparatus 10 according to the first embodiment can acquire approximate elastic values for tissues in various states, and enables SWE to be performed under acquisition conditions suitable for tissues in various states.

[0095] Also, according to the first embodiment, the analysis function 421 calculates the degree of the elastic value in the tissue of the subject based on the shear wave. Therefore, the ultrasonic diagnostic apparatus 10 according to the first embodiment can acquire an approximate elastic value and enables easy acquisition of appropriate acquisition conditions.

[0096] Also, according to the first embodiment, the setting function 412 selects the acquisition condition of the scan data from among a plurality of pre-set acquisition conditions based on an index. Further, the setting function 412 inputs an index to a model that outputs the acquisition condition of the scan data in response to the input of the index, thereby acquiring the acquisition condition of the scan data. Therefore, the ultrasonic diagnostic apparatus 10 according to the first embodiment enables easy acquisition of appropriate acquisition conditions.

[0097] Also, according to the first embodiment, the setting function 412 sets at least one of the time from the acquisition of the biological signal to the start of the acquisition of the scan data and the time from the acquisition of the scan data to the start of the acquisition of the next scan data based on an index. Therefore, the ultrasonic diagnostic apparatus 10 according to the first embodiment enables SWE to be performed with an appropriate cool time.

[0098] Also, according to the first embodiment, the control function 451 controls to display the index on the display 2. Therefore, the ultrasonic diagnostic apparatus 10 according to the first embodiment can present an index (for example, an elastic value) obtained by pre-scan to the operator.

[0099] Also, according to the first embodiment, when the index does not satisfy the standard, the control function 451 controls to display warning information regarding the index. Therefore, the ultrasonic diagnostic apparatus 10 according to the first embodiment can notify the operator when the analysis of the pre-scan is not appropriate.

[0100] Also, according to the first embodiment, after a biological signal is acquired, when a plurality of scan data are continuously acquired, the setting function 412 sets the transmission condition of the push pulse for observing the shear wave and the transmission / reception condition of the tracking pulse based on an index. The acquisition function 411 acquires a plurality of scan data under the set transmission condition of the push pulse and the transmission / reception condition of the tracking pulse. Therefore, the ultrasonic diagnostic apparatus 10 according to the first embodiment can acquire appropriate scan data even when acquiring a plurality of scan data in this scan.

[0101] Also, according to the first embodiment, as acquisition conditions for scan data, the setting function 412 sets at least one of the transmission condition of the push pulse for observing the shear wave and the transmission / reception condition of the tracking pulse, the condition regarding display based on the scan data, and the condition regarding analysis based on the scan data. Therefore, the ultrasonic diagnostic apparatus 10 according to the first embodiment can appropriately set various conditions related to this scan.

[0102] Also, according to the first embodiment, the memory circuit 44 stores the acquisition conditions for scan data. The acquisition function 411 reads out the acquisition conditions for scan data from the memory circuit 44 and acquires scan data based on the read acquisition conditions. Therefore, the ultrasonic diagnostic apparatus 10 according to the first embodiment can omit the pre-scan and shorten the inspection time.

[0103] Also, according to the first embodiment, based on the analysis result of the first shear wave obtained by executing the pre-scan, the setting function 412 sets, as the acquisition conditions for scan data, a condition including at least one of the position and size of the second measurement region R2. Thereby, as shown in FIG. 9A, regardless of the viscoelastic state of the tissue to be measured, the shear wave can be measured within a region (second measurement region R2) suitable for the measurement target.

[0104] Also, according to the first embodiment, the setting function 412 sets, as acquisition conditions for scan data, conditions including at least any one of the measurement start time of the second shear wave, the measurement end time of the second shear wave, and the measurement time width at each position of the second measurement region R2 based on the analysis result of the first shear wave obtained by performing a pre-scan. Thereby, as shown in FIG. 9B, regardless of the viscoelasticity of the tissue to be measured, the shear wave can be measured within a time (measurement time) suitable for the measurement target.

[0105] (Other Embodiments) In the above-described embodiment, the case where acquisition conditions are set based on a single analysis result (the velocity range of the propagation velocity of the shear wave) has been described. However, the embodiment is not limited to this, and for example, acquisition conditions may be set in detail based on a plurality of analysis results (for example, an analysis result based on the propagation velocity and an analysis result based on waveform information).

[0106] Also, in the above-described embodiment, the case where a shear wave is used as the biological signal of the subject has been described. However, the embodiment is not limited to this, and a reflected wave data acquired by a B-mode scan may be used as the biological signal. That is, the elastic value of the tissue may be estimated based on the B-mode reflected wave data.

[0107] Further, in the above-described embodiment, the case where an elastic value is used as an index has been described. However, the embodiment is not limited to this, and a viscous value may be used as an index. That is, the case where the viscosity of the tissue is analyzed based on the shear wave may also be used. In this case, the control function 451 may cause the display 2 to display evaluation information (for example, an SWD (Shear Wave Dispersion) image, a viscosity image, etc.) based on the scan data acquired by the acquisition function 411. For example, the control function 451 causes the display 2 to display a hardness image (SWD image) in which a color corresponding to the viscous value (viscosity coefficient, dispersion value (Dispersion Slope value) of the propagation speed with respect to the frequency component) at each position in the second measurement region R2 is assigned to each position (for example, each pixel) in the second measurement region R2.

[0108] Further, in the above-described embodiment, as shown in FIG. 8, an example has been described in which the first measurement region R1 set in the pre-scan is smaller than the second measurement region R2 set in this scan. However, the first measurement region R1 may be the same as or larger than the second measurement region R2.

[0109] Further, in the above-described embodiment, as shown in FIG. 6, only an example has been described in which a range "10 kPa - 30 kPa" corresponding to the statistical value (average value, median value, range, etc.) of the elastic value in the first measurement region R1 measured in the pre-scan is selected from among a plurality of ranges. However, information regarding this may be displayed on the display 2 during the execution of the pre-scan and this scan.

[0110] For example, the control function 451 may display an indicator indicating the position of the acquisition condition set by the setting function 412 within the range in which the acquisition condition of the scan data can be set. Specifically, as shown in FIG. 10, an indicator indicating the acquisition condition of the scan data for measuring the propagation speed of the shear wave according to the viscoelastic state of the tissue is used. The control function 451 causes the display 2 to display an indicator indicating the acquisition condition (for low speed, for low to medium speed, for medium to high speed, for high speed) of the scan data suitable for each of the ranges from hard tissue to soft tissue.

[0111] Further, the control function 451 may display an ultrasonic image (SWE image, SWD image, etc.) based on the scan data of the subject (scan data of this scan) acquired by the acquisition function 411 and an indicator side by side. For example, as shown in FIG. 11, the control function 451 displays corresponding indicators on the display 2 during the execution of the pre-scan and this scan. The control function 451 may display an indicator until an ultrasonic image (SWE image, SWD image, etc.) based on the scan data of the subject acquired by the acquisition function 411 is displayed in response to the scan data acquisition conditions being set by the setting function 412. Thereby, before the ultrasonic image based on the scan data of this scan is displayed on the display 2, the operator can confirm the scan data acquisition conditions (any one of low speed, low-medium speed, medium-high speed, and high speed shown in FIG. 10) indicated by the indicator.

[0112] Also, in the above-described embodiment, the setting function 412 has been described as an example of setting the scan data acquisition conditions based on the analysis result of the first shear wave propagated through the first measurement region by the pre-scan. However, alternatively, the scan data acquisition conditions may be set based on at least one of the B-mode data and Doppler data of the subject and the analysis result of the first shear wave. Thereby, in addition to the analysis result of the first shear wave, it is possible to set the scan data acquisition conditions that also reflect the form of the subject's tissue represented by the B-mode data and the state of the subject's blood flow represented by the Doppler data.

[0113] Further, the setting function 412 has been described with an example of setting the acquisition conditions of scan data for measuring the second shear wave to be generated in the second measurement region R2 by this scan based on the analysis result of the first shear wave propagated through the first measurement region R1 by pre-scan. However, based on the analysis result of the first shear wave, the acquisition conditions of scan data related to at least one of the B-mode data and Doppler data of the subject may be set. Thereby, considering the state of the tissue properties (viscoelasticity) of the subject, scan data related to at least one of the B-mode data and Doppler data of the subject can be newly acquired.

[0114] Also, for example, diffuse liver diseases (such as hepatitis, liver cirrhosis, fatty liver, etc.) are diseases in which the tissue properties of the entire liver change, so shear waves propagate uniformly within the liver. However, when there are other structures (blood vessels, cysts) in the liver, the shear waves propagate non-uniformly, and the analysis results of the shear waves measured at such parts are of low reliability. Therefore, the analysis function 421 may acquire, as the analysis result of the shear wave, a reliability index value indicating the reliability of the propagation of the first shear wave at each position in the first measurement region R1. For example, the analysis function 421 compares the parameters (elastic index values (such as propagation velocity, etc.)) based on the first shear wave obtained at each position in the first measurement region R1 with the surroundings, and thereby acquires a value (such as a difference value, standard deviation, etc.) indicating whether it is non-uniform compared to the surroundings as the reliability index value. And in this case, the setting function 412 may set the acquisition conditions of the scan data based on the reliability index value at each position in the first measurement region R1. For example, the setting function 412 identifies positions in the first measurement region R1 where the reliability index value is smaller than the threshold value (that is, the reliability is low), and based on the analysis result of the first shear wave obtained at the part excluding those positions, sets the acquisition conditions of the scan data for this scan (this SWE).

[0115] Further, the analysis function 421 may obtain a reliability index value indicating the reliability of the scan in the subject based on the analysis result of the shear wave propagated in the first measurement region R1 and at least one of the B-mode data and Doppler data of the subject. That is, in addition to the analysis result of the first shear wave, the morphology of the tissue of the subject represented by the B-mode data and the blood flow state of the subject represented by the Doppler data may be comprehensively analyzed to obtain a reliability index value indicating the reliability of the scan in the subject. The reliability index value is, for example, an index value for identifying whether the shear wave becomes non-uniform due to factors such as structures such as blood vessels and cysts, regions where the shear wave is weak, and regions with movement. That is, the reliability index value can also be said to be an index value indicating the stability (reliability of the scan) of the scan. Then, the setting function 412 may set the acquisition conditions of the scan data based on the reliability index value obtained by the analysis function 421. That is, based on the reliability index value obtained by comprehensively analyzing the morphology, properties, and blood flow state of the tissue, the acquisition conditions of the scan data for performing the scan in a region with high scan stability and reliability may be set.

[0116] In addition, in the previous description, an example in which the first measurement region R1 for analyzing the first shear wave by the analysis function 421 is single has been described. However, the first measurement region R1 may be plural (for example, five). The plural measurement regions R1 may be arranged continuously (arranged so as to be in contact with each other) or discretely (arranged so as to be separated from each other). In this case, the analysis function 421 analyzes the shear waves propagated through the plural different regions of the subject, and the setting function 412 may set the acquisition conditions of the scan data based on the analysis results of the shear waves corresponding to the plural different regions respectively. That is, based on the analysis results of the shear for the plural measurement regions (the first measurement region R1), the scan data may be acquired under conditions more suitable for the measurement target. For example, the setting function 412 excludes the analysis results (for example, two analysis results) in which the difference (deviation) from the average of the analysis results among the analysis results (for example, the statistical values of the elastic index values) of the first shear wave obtained in each of the five first measurement regions R1 is larger than a predetermined threshold value. Thereby, the setting function 412 regards the three analysis results (the analysis results with the deviation being equal to or less than the threshold value) not excluded as highly reliable, and may set the acquisition conditions of the scan data based on the three analysis results.

[0117] Note that the term "processor" used in the above description means, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), or a circuit such as an application specific integrated circuit (ASIC), a programmable logic device (e.g., a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), and a field programmable gate array (FPGA)). The processor realizes its functions by reading and executing a program stored in a memory. Instead of storing the program in the memory, the program may be directly incorporated into the circuit of the processor. In this case, the processor realizes its functions by reading and executing the program incorporated into the circuit. Note that each processor of the present embodiment is not limited to being configured as a single circuit for each processor, and a plurality of independent circuits may be combined to be configured as one processor to realize its functions.

[0118] Note that each component of each device illustrated in the description of the above embodiment is functionally conceptual and does not necessarily have to be physically configured as illustrated. That is, the specific form of the distribution and integration of each device is not limited to that illustrated, and all or part of it can be functionally or physically distributed and integrated in any unit according to various loads, usage situations, etc. Furthermore, each processing function performed by each device can be realized in whole or in any part by a CPU and a program analyzed and executed by the CPU, or can be realized as hardware by wired logic.

[0119] In addition, the method described in the above-described embodiments can be realized by executing a program prepared in advance on a computer such as a personal computer or a workstation. This program can be distributed via a network such as the Internet. Further, this program is recorded on a non-transitory computer-readable recording medium such as a hard disk, a flexible disk (FD), a CD-ROM, an MO, a DVD, a USB memory, and an SD card memory, and can also be executed by being read from the non-transitory recording medium by a computer.

[0120] As described above, according to the embodiment, it is possible to perform measurement under conditions suitable for the measurement target.

[0121] 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, replacements, changes, and combinations of the embodiments can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalent scope thereof.

[0122] Regarding the above embodiments and the like, the following supplementary notes are disclosed as one aspect and selective features of the invention.

[0123] (Supplementary Note 1) The ultrasonic diagnostic apparatus includes a first acquisition unit that transmits and receives ultrasonic waves for observing shear waves in a subject to acquire scan data, a second acquisition unit that acquires a biological signal of the subject before the acquisition of the scan data, an analysis unit that calculates an index for determining acquisition conditions of the scan data based on the biological signal, and a setting unit that sets the acquisition conditions of the scan data based on the index. The ultrasonic diagnostic apparatus is provided with the above components.

[0124] (Appendix 2) The second acquisition unit may acquire, as the biological signal, a shear wave acquired by transmitting a push pulse and transmitting and receiving a tracking pulse.

[0125] (Appendix 3) The second acquisition unit may execute transmission of the push pulse and transmission and reception of the tracking pulse under acquisition conditions that enable acquisition of each shear wave propagating through tissues with different tissue properties.

[0126] (Appendix 4) The analysis unit may calculate the degree of the elastic value in the tissue of the subject based on the shear wave.

[0127] (Appendix 5) The setting unit may select the acquisition conditions for the scan data from among a plurality of pre-set acquisition conditions based on the index.

[0128] (Appendix 6) The setting unit may acquire the acquisition conditions for the scan data by inputting the index to a model that outputs the acquisition conditions for the scan data in response to the input of the index.

[0129] (Appendix 7) The setting unit may set at least one of the time from acquisition of the biological signal to start of acquisition of the scan data and the time from acquisition of the scan data to start of acquisition of the next scan data based on the index.

[0130] (Appendix 8) The apparatus may further include a display control unit that controls to display the index on a display unit.

[0131] (Appendix 9) The display control unit may control to display warning information regarding the index when the index does not satisfy a standard.

[0132] (Appendix 10) After the biological signal is acquired, when a plurality of scan data are continuously acquired, the setting unit sets the transmission condition of the push pulse and the transmission / reception condition of the tracking pulse for observing the shear wave based on the index, The first acquisition unit may acquire the plurality of scan data under the set transmission condition of the push pulse and the transmission / reception condition of the tracking pulse.

[0133] (Appendix 11) The apparatus further includes a storage unit that stores the acquisition condition of the scan data, The first acquisition unit may read the acquisition condition of the scan data from the storage unit and acquire the scan data based on the read acquisition condition.

[0134] (Appendix 12) As the acquisition condition of the scan data, the setting unit may set at least one of the transmission condition of the push pulse and the transmission / reception condition of the tracking pulse for observing the shear wave, the condition related to the display based on the scan data, and the condition related to the analysis based on the scan data.

[0135] (Appendix 13) The method includes: acquiring a biological signal of the subject before transmitting and receiving ultrasonic waves for observing a shear wave in the subject to acquire scan data, calculating an index for determining an acquisition condition of the scan data based on the biological signal, setting the acquisition condition of the scan data based on the index, acquiring the scan data based on the acquisition condition. This includes.

[0136] (Appendix 14) The program includes: Before acquiring scan data by transmitting and receiving ultrasonic waves for observing shear waves in a subject, acquire a biological signal of the subject, Based on the biological signal, calculate an index for determining acquisition conditions of the scan data, Based on the index, set the acquisition conditions of the scan data, Based on the acquisition conditions, acquire the scan data, Cause a computer to execute each process.

[0137] (Appendix 15) An ultrasonic diagnostic apparatus includes an analysis unit that analyzes a shear wave propagated through a subject, a setting unit that sets acquisition conditions of scan data based on an analysis result of the shear wave, and an acquisition unit that executes a scan on the subject based on the acquisition conditions and acquires scan data of the subject.

[0138] (Appendix 16) The analysis unit analyzes a first shear wave propagated through each position of a first measurement region of the subject, Based on the analysis result of the first shear wave, the setting unit may set, as the acquisition conditions of the scan data, transmission conditions of a push pulse that generates a second shear wave in a second measurement region of the subject and transmission / reception conditions of a tracking pulse that observes the second shear wave.

[0139] (Appendix 17) The first measurement region may be smaller than the second measurement region.

[0140] (Appendix 18) Based on the analysis result of the first shear wave, the setting unit may set, as the acquisition conditions of the scan data, a condition including at least one of a position and a size of the second measurement region.

[0141] (Appendix 19) Based on the analysis result of the first shear wave, the setting unit may set, as the acquisition condition of the scan data, a condition including at least any one of the measurement start time of the second shear wave, the measurement end time of the second shear wave, and the measurement time width at each position of the second measurement region.

[0142] (Appendix 20) The analysis unit acquires, as the analysis result of the shear wave, a tissue property index value indicating the tissue property of the subject at each position in the first measurement region. Based on the tissue property index value at each position in the first measurement region, the setting unit may set the acquisition condition of the scan data.

[0143] (Appendix 21) The tissue property index value may be at least one of an elasticity index value indicating the elasticity of the tissue of the subject and a viscosity index value indicating the viscosity of the tissue of the subject.

[0144] (Appendix 22) The analysis unit acquires, as the analysis result of the shear wave, a reliability index value indicating the reliability of the propagation of the first shear wave at each position in the first measurement region. Based on the reliability index value at each position in the first measurement region, the setting unit may set the acquisition condition of the scan data.

[0145] (Appendix 23) The setting unit may input the analysis result of the shear wave analyzed by the analysis unit to a model that outputs the acquisition condition of the scan data in response to the input of the analysis result of the shear wave, and set the acquisition condition of the scan data output by the model.

[0146] (Appendix 24) It may be provided with a control unit that displays an ultrasonic image based on the scan data of the subject acquired by the acquisition unit.

[0147] (Appendix 25) In the range where the acquisition conditions of the scan data can be set, a control unit may be provided that displays an indicator indicating the position of the acquisition conditions set by the setting unit.

[0148] (Appendix 26) The control unit may display the ultrasonic image based on the scan data of the subject acquired by the acquisition unit and the indicator side by side.

[0149] (Appendix 27) The control unit may display the indicator until the ultrasonic image based on the scan data of the subject acquired by the acquisition unit is displayed in response to the acquisition conditions of the scan data being set by the setting unit.

[0150] (Appendix 28) The setting unit may set the acquisition conditions of the scan data based on at least one of the B-mode data and Doppler data of the subject and the analysis result of the shear wave.

[0151] (Appendix 29) The setting unit may set the acquisition conditions of the scan data related to at least one of the B-mode data and Doppler data of the subject based on the analysis result of the shear wave.

[0152] (Appendix 30) The analysis unit analyzes the shear waves propagated through a plurality of different regions of the subject, and may set the acquisition conditions of the scan data based on the analysis results of the shear waves corresponding to each of the plurality of different regions.

[0153] (Appendix 31) The method is, analyzing the shear wave propagated through the subject, setting the acquisition conditions of the scan data based on the analysis result of the shear wave, performing a scan on the subject based on the acquisition conditions, Acquire the scan data of the subject.

[0154] (Appendix 32) The program causes the computer to function as an analysis unit that analyzes shear waves propagated through the subject, a setting unit that sets acquisition conditions for the scan data based on the analysis result of the shear waves, and an acquisition unit that performs a scan on the subject based on the acquisition conditions and acquires the scan data of the subject.

Explanation of Reference Signs

[0155] 10 Ultrasonic diagnostic apparatus 411 Acquisition function 412 Setting function 421 Analysis function 451 Control function R1 First measurement region R2 Second measurement region

Claims

1. An analysis unit that analyzes shear waves propagated through a subject, A setting unit that sets acquisition conditions for scan data based on the analysis result of the shear wave, An acquisition unit that performs a scan on the subject based on the acquisition conditions and acquires scan data of the subject, An ultrasonic diagnostic apparatus.

2. The analysis unit analyzes a first shear wave propagated through each position in a first measurement region of the subject, The setting unit sets, as the acquisition conditions for the scan data, transmission conditions for a push pulse that generates a second shear wave in a second measurement region of the subject and transmission / reception conditions for a tracking pulse that observes the second shear wave, based on the analysis result of the first shear wave. The ultrasonic diagnostic apparatus according to Claim 1.

3. The first measurement region is smaller than the second measurement region. The ultrasonic diagnostic apparatus according to Claim 2.

4. The setting unit sets, as the acquisition conditions for the scan data, a condition including at least one of the position and size of the second measurement region, based on the analysis result of the first shear wave. The ultrasonic diagnostic apparatus according to Claim 2.

5. The setting unit sets, as the acquisition conditions for the scan data, a condition including at least any one of the measurement start time of the second shear wave, the measurement end time of the second shear wave, and the measurement time width at each position of the second measurement region, based on the analysis result of the first shear wave. The ultrasonic diagnostic apparatus according to Claim 2.

6. The analysis unit acquires, as the analysis result of the shear wave, a tissue property index value indicating the tissue property of the subject at each position in the first measurement region of the subject, The setting unit sets the acquisition conditions for the scan data based on the tissue property index value at each position in the first measurement region. The ultrasonic diagnostic apparatus according to Claim 1.

7. The tissue property index value is at least one of an elasticity index value indicating the elasticity of the tissue of the subject and a viscosity index value indicating the viscosity of the tissue of the subject. The ultrasonic diagnostic apparatus according to Claim 6.

8. The analysis unit acquires, as the analysis result of the shear wave, a reliability index value indicating the reliability of the propagation of the first shear wave at each position in the first measurement region, The setting unit sets the acquisition conditions for the scan data based on the reliability index value at each position in the first measurement region. The ultrasonic diagnostic apparatus according to Claim 2.

9. The setting unit inputs the analysis result of the shear wave analyzed by the analysis unit to a model that outputs acquisition conditions of scan data in response to the input of the analysis result of the shear wave, and sets the acquisition conditions of the scan data output by the model. The ultrasonic diagnostic apparatus according to claim 1.

10. It includes a control unit that displays an ultrasonic image based on the scan data of the subject acquired by the acquisition unit. The ultrasonic diagnostic apparatus according to claim 1.

11. It includes a control unit that displays an indicator indicating the position of the acquisition conditions set by the setting unit within the range where the acquisition conditions of the scan data can be set. The ultrasonic diagnostic apparatus according to claim 1.

12. The control unit displays the ultrasonic image and the indicator side by side based on the scan data of the subject acquired by the acquisition unit. The ultrasonic diagnostic apparatus according to claim 11.

13. The control unit displays the indicator until an ultrasonic image based on the scan data of the subject acquired by the acquisition unit is displayed in response to the acquisition conditions of the scan data being set by the setting unit. The ultrasonic diagnostic apparatus according to claim 11.

14. The setting unit sets the acquisition conditions of the scan data based on at least one of the B-mode data and Doppler data of the subject and the analysis result of the shear wave. The ultrasonic diagnostic apparatus according to claim 1.

15. The setting unit sets the acquisition conditions of the scan data related to at least one of the B-mode data and Doppler data of the subject based on the analysis result of the shear wave. The ultrasonic diagnostic apparatus according to claim 1.

16. The analysis unit analyzes shear waves propagated through a plurality of different regions of the subject respectively. Based on the analysis results of the shear waves corresponding to the plurality of different regions respectively, it sets the acquisition conditions of the scan data. The ultrasonic diagnostic apparatus according to claim 1.

17. It analyzes the shear wave propagated through the subject. Based on the analysis result of the shear wave, it sets the acquisition conditions of the scan data. Based on the acquisition conditions, it performs a scan on the subject. It acquires the scan data of the subject. Method.

18. A computer, An analysis unit that analyzes the shear wave propagated through the subject, A setting unit that sets acquisition conditions for scan data based on the analysis result of the shear wave, and A program that functions as an acquisition unit that performs a scan on the subject based on the acquisition conditions and acquires scan data of the subject. Program.

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