JP6289225B2 - Ultrasonic diagnostic apparatus and control program - Google Patents

Description

  Embodiments described herein relate generally to an ultrasonic diagnostic apparatus and a control program.

  Conventionally, elastography is known as a technique for visualizing the hardness of a living tissue of a subject. In elastography, a push pulse, which is a focused ultrasonic pulse having a high sound pressure, is transmitted from an ultrasonic probe, and the propagation speed of a shear wave generated in the subject is measured with a tracking pulse. The hardness is evaluated.

  In order to generate a shear wave, the push pulse used in elastography uses a stronger ultrasonic pulse as compared with an ultrasonic pulse or tracking pulse for B-mode tomography. The mechanical impact that the push pulse gives to the subject increases in accordance with the transmission output of the push pulse, and thus becomes larger than other ultrasonic pulses.

  However, in the past, the strength of the push pulse could not be adjusted, and depending on the subject, the mechanical shock due to the push pulse was weak, and the detection sensitivity of the shear wave was reduced, or the mechanical shock was wasted. It was. For example, in a subject with thick subcutaneous fat, it is necessary to measure the propagation velocity in the region of interest (ROI) where the hardness of the living tissue is measured unless the push pulse transmission output is increased to some extent. May not generate sufficient shear waves, and the sensitivity of shear wave detection may be reduced. Conversely, in a subject with thin subcutaneous fat, unless the push pulse transmission output is weakened to some extent, a mechanical shock more than necessary to generate a shear wave in the region of interest may be applied.

JP 2013-27512 A

  The problem to be solved by the present invention is to provide an ultrasonic diagnostic apparatus and program capable of adjusting the intensity of ultrasonic waves for generating a shear wave in a subject.

The ultrasonic diagnostic apparatus according to the embodiment includes a transmission / reception unit, a reception unit, and a control unit. The transmission / reception unit causes the ultrasonic probe to transmit a first ultrasonic wave for generating a shear wave in the subject, and transmits / receives a second ultrasonic wave for measuring the propagation speed of the shear wave by the ultrasonic probe. The accepting unit accepts setting of an index value related to the first ultrasound. The control unit controls the intensity of transmission of the first ultrasonic wave based on the set index value and performs transmission and reception of the second ultrasonic wave with respect to the transmission of the first ultrasonic wave. The width is controlled according to the strength of the transmission. The reception unit receives a setting of a region of interest in the subject. The control unit divides the set region of interest based on a scan width for transmitting and receiving the second ultrasonic wave, and transmits the first ultrasonic wave for each divided region of interest, The transmission / reception of the second ultrasonic wave with the scanning width is performed.

FIG. 1 is a block diagram illustrating a configuration example of the ultrasonic diagnostic apparatus according to the first embodiment. FIG. 2 is an explanatory diagram for explaining push pulses and shear waves. FIG. 3 is an explanatory diagram showing an example of hardness image data. FIG. 4 is a flowchart illustrating an example of the operation of the ultrasonic diagnostic apparatus according to the first embodiment. FIG. 5 is an explanatory diagram illustrating an example of a monitor display screen. FIG. 6 is an explanatory diagram illustrating an example of a monitor display screen. FIG. 7 is a flowchart illustrating an example of the hardness image data generation process. FIG. 8 is a flowchart illustrating an example of the operation of the ultrasonic diagnostic apparatus according to the second embodiment. FIG. 9 is an explanatory diagram for explaining transmission / reception timings of the B-mode pulse, push pulse, and tracking pulse.

  Hereinafter, an ultrasonic diagnostic apparatus and a program according to embodiments will be described in detail with reference to the accompanying drawings. In the following description, common constituent elements are given common reference numerals, and redundant description is omitted.

(First embodiment)
FIG. 1 is a block diagram illustrating a configuration example of the ultrasonic diagnostic apparatus according to the first embodiment. The ultrasonic diagnostic apparatus according to the first embodiment is an apparatus capable of performing elastography. In elastography, an image (hardness image) that visualizes the hardness of a living tissue is generated and displayed. As shown in FIG. 1, the ultrasonic diagnostic apparatus according to the first embodiment includes an ultrasonic probe 1, a monitor 2, an input unit 3, and an apparatus main body 10.

  The ultrasonic probe 1 has a plurality of transducers. The plurality of transducers in the ultrasonic probe 1 transmit ultrasonic waves based on a drive signal supplied from the transmission / reception unit 11 included in the apparatus main body 10. The vibrator included in the ultrasonic probe 1 is, for example, a piezoelectric vibrator. The ultrasonic probe 1 receives a reflected wave signal from the subject P and converts it into an electrical signal. The ultrasonic probe 1 includes a matching layer provided in the piezoelectric vibrator, a backing material that prevents propagation of ultrasonic waves from the piezoelectric vibrator to the rear, and the like. The ultrasonic probe 1 is detachably connected to the apparatus main body 10.

  When an ultrasonic wave is transmitted from the ultrasonic probe 1 to the subject P, the transmitted ultrasonic waves are reflected one after another at the discontinuous surface of the acoustic impedance in the living tissue in the body of the subject P, and as a reflected wave signal It is received by a plurality of piezoelectric vibrators possessed by the ultrasonic probe 1. 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. Note that the reflected wave signal when the transmitted ultrasonic pulse is reflected by the moving blood flow or the surface of the heart wall depends on the velocity component of the moving object in the ultrasonic transmission direction due to the Doppler effect. And undergoes a frequency shift.

  In the first embodiment, the ultrasonic probe 1 shown in FIG. 1 is a one-dimensional ultrasonic probe in which a plurality of piezoelectric vibrators are arranged in a line, or a plurality of piezoelectric vibrators arranged in a line. Is a mechanically oscillating one-dimensional ultrasonic probe, and can be applied to any of the two-dimensional ultrasonic probes in which a plurality of piezoelectric vibrators are arranged two-dimensionally in a lattice shape. .

  The monitor 2 displays a GUI (Graphical User Interface) for an operator of the ultrasonic diagnostic apparatus to input various setting requests using the input unit 3, and displays ultrasonic image data generated in the apparatus main body 10. It is a display device that displays.

  The input unit 3 receives input of various requests from the operator of the ultrasonic diagnostic apparatus, and transfers the received various requests to the apparatus main body 10. The input unit 3 is a mouse, a keyboard, a button, a panel switch, a touch command screen, a foot switch, a trackball, or the like. For example, the input unit 3 receives an input of a hardness image display request, various setting requests, and setting contents from an operator, and outputs the received hardness image display request, various setting requests, and setting contents to the control unit 17. To do. The hardness image display request is an example of a request for transmitting an ultrasonic wave for deforming the living tissue of the subject P.

  The apparatus main body 10 is an apparatus that generates ultrasonic image data based on a reflected wave signal received by the ultrasonic probe 1. The apparatus main body 10 includes a transmission / reception unit 11, a B-mode processing unit 12, a Doppler processing unit 13, an image generation unit 14, an image memory 15, an internal storage unit 16, and a control unit 17.

  The transmission / reception unit 11 controls ultrasonic transmission / reception performed by the ultrasonic probe 1 based on an instruction from the control unit 17. The transmission / reception unit 11 includes a pulse generator, a transmission delay unit, a pulser, and the like, 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 generates a delay time for each piezoelectric vibrator necessary for focusing the ultrasonic wave generated from the ultrasonic probe 1 into a beam and determining transmission directivity. Give for each rate pulse. The pulser applies a drive signal (drive pulse) to the ultrasonic probe 1 at a timing based on the rate pulse. The transmission delay unit arbitrarily adjusts the transmission direction of the ultrasonic wave transmitted from the piezoelectric vibrator surface by changing the delay time given to each rate pulse.

  The transmission / reception unit 11 has a function capable of instantaneously changing a transmission frequency, a transmission drive voltage, a transmission drive current, and the like in order to execute a predetermined scan sequence based on an instruction from the control unit 17. In particular, the change of the transmission drive voltage is realized by a linear amplifier type transmission circuit whose value can be switched instantaneously, or a mechanism for electrically switching a plurality of power supply voltages and transmitting a rectangular pulse.

  The transmission / reception unit 11 includes a preamplifier, an A / D (Analog / Digital) converter, a reception delay unit, an adder, and the like. The transmission / reception unit 11 performs various processing on the reflected wave signal received by the ultrasonic probe 1 and reflects it. Generate wave data. The preamplifier amplifies the reflected wave signal for each channel. The A / D converter A / D converts the amplified reflected wave signal. The reception delay unit gives a delay time necessary for determining the reception directivity. The adder performs an addition process of the reflected wave signal processed by the reception delay unit to generate reflected wave data. By the addition processing 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 for ultrasonic transmission / reception is formed by the reception directivity and the transmission directivity.

  The transmitter / receiver 11 transmits a two-dimensional ultrasonic beam from the ultrasonic probe 1 when the subject P is two-dimensionally scanned. Then, the transmission / reception unit 11 generates two-dimensional reflected wave data from the two-dimensional reflected wave signal received by the ultrasonic probe 1. Further, when the subject P is three-dimensionally scanned, the transmission / reception unit 11 transmits a three-dimensional ultrasonic beam from the ultrasonic probe 1. Then, the transmission / reception unit 11 generates three-dimensional reflected wave data from the three-dimensional reflected wave signal received by the ultrasonic probe 1.

  The form of the output signal from the transmission / reception unit 11 can be selected from various forms such as a signal including phase information called an RF (Radio Frequency) signal or amplitude information after envelope detection processing. Is possible.

  In addition, when receiving a hardness image display request, the transmission / reception unit 11 shears the living tissue of the subject P by transmitting a push pulse from the ultrasonic probe 1 based on an instruction from the control unit 17. Generate a wave.

  FIG. 2 is an explanatory diagram for explaining push pulses and shear waves. For example, as shown in FIG. 2, the transmission / reception unit 11 causes the ultrasonic probe 1 to perform ultrasonic irradiation (push pulse) of about 1000 waves at several tens of volts with one point of the focal position 2a as a focal point. This push pulse is an ultrasonic wave transmitted to deform the living tissue of the subject P and generate the shear wave 2b in the deformed living tissue. In this way, the push pulse is not an ultrasound directly used for imaging a living tissue, unlike an ultrasound directly used for imaging a living tissue such as a B-mode pulse or a tracking pulse.

  Then, the transmission / reception unit 11 generates the shear wave 2b in the lateral direction (lateral direction) by transmitting the push pulse while shifting the focus to a deep position along the focus position 2a. Subsequently, the transmission / reception unit 11 causes the ultrasonic probe 1 to transmit a tracking pulse 3a for shear wave measurement based on an instruction from the control unit 17 in order to measure the propagation speed of the generated shear wave 2b. The push pulse is an example of an ultrasonic wave that is transmitted to deform the living tissue of the subject P and generate the shear wave 2b.

  The B-mode processing unit 12 and the Doppler processing unit 13 are signal processing units that perform various types of signal processing on the reflected wave data generated from the reflected wave signal by the transmission / reception unit 11. The B-mode processing unit 12 receives the reflected wave data from the transmission / reception unit 11, performs logarithmic amplification, envelope detection processing, and the like, and generates data (B-mode data) in which the signal intensity is expressed by brightness. . Further, the Doppler processing unit 13 performs frequency analysis on velocity information from the reflected wave data received from the transmission / reception unit 11 and extracts data (Doppler data) obtained by extracting moving body information such as velocity, dispersion, and power due to the Doppler effect at multiple points. Generate. Here, the moving body is, for example, a blood flow, a tissue such as a heart wall, or a contrast agent.

  Here, the ultrasonic diagnostic apparatus is an apparatus capable of performing elastography that measures the hardness of a living tissue and visualizes the distribution of the measured hardness. An ultrasonic diagnostic apparatus is an apparatus capable of performing elastography by applying an acoustic radiation force to generate a displacement in a living tissue.

  That is, the transmission / reception unit 11 causes the ultrasonic probe 1 to transmit a displacement-generating ultrasonic wave (push pulse) that generates a displacement by a shear wave generated by an acoustic radiation force. Then, the transmission / reception unit 11 transmits observation ultrasonic waves (tracking pulse 3a) for observing the displacement generated by the push pulse from the ultrasonic probe 1 a plurality of times on each of the plurality of scanning lines in the scanning region. The tracking pulse 3a is transmitted in order to observe the propagation speed of the shear wave generated by the push pulse at each sample point in the scanning region. Usually, the tracking pulse 3a is transmitted a plurality of times (for example, 100 times) to each scanning line in the scanning region. The B-mode processing unit 12 generates reflected wave data from the reflected wave signal of the observation pulse transmitted on each scanning line in the scanning region.

  Then, the Doppler processing unit 13 analyzes the reflected wave data of the tracking pulse 3a transmitted a plurality of times on each scanning line in the scanning region, and calculates hardness distribution information indicating the hardness distribution of the scanning region. Specifically, the Doppler processing unit 13 generates the hardness distribution information of the scanning region by measuring the propagation speed of the shear wave generated by the push pulse at each sample point.

  For example, the Doppler processing unit 13 performs frequency analysis on the reflected wave data of the tracking pulse 3a. Thereby, the Doppler processing unit 13 generates motion information (tissue Doppler data) over a plurality of time phases at each of a plurality of sample points of each scanning line. Then, the Doppler processing unit 13 time-integrates the velocity components of the plurality of time-phase tissue Doppler data obtained at each of the plurality of sample points of each scanning line. Thereby, the Doppler processing unit 13 calculates the displacement of each of the plurality of sample points of each scanning line over a plurality of time phases. Subsequently, the Doppler processing unit 13 obtains a time at which the displacement is maximum at each sample point. And the Doppler process part 13 acquires the time when the maximum displacement was acquired at each sample point as the arrival time of the shear breaking wave in each sample point. Subsequently, the Doppler processing unit 13 calculates the propagation speed of the shear wave at each sample point by performing spatial differentiation of the arrival time of the shear wave at each sample point. Hereinafter, “shear wave propagation velocity” is referred to as “shear velocity”.

  And the Doppler process part 13 color-codes a shear rate, and produces | generates hardness distribution information by mapping to a corresponding sample point. A hard tissue has a high shear rate, and a soft tissue has a low shear rate. That is, the value of the shear rate is a value indicating the hardness (elastic modulus) of the tissue. In the above case, the tracking pulse 3a is a transmission pulse for tissue Doppler. Note that the shear rate is calculated not by the Doppler processing unit 13 based on the time at which the displacement is maximum at each sample point but by being detected by the cross-correlation of the tissue displacement in the adjacent scanning line. There may be.

  The Doppler processing unit 13 may calculate the Young's modulus or shear elastic modulus from the shear rate, and may generate the hardness distribution information based on the calculated Young's modulus or shear elastic modulus. The shear rate, Young's modulus, and shear modulus can all be used as physical quantities representing the hardness of the living tissue. Below, the case where the Doppler process part 13 uses a shear rate as a physical quantity showing the hardness of a biological tissue is demonstrated.

  Here, the shear wave generated by one push pulse transmission attenuates with propagation. When attempting to observe the shear rate over a wide area, the shear wave generated by the push pulse transmitted in one specific scan line is attenuated as it propagates, and will eventually be observed once it is sufficiently far from the push pulse position. It becomes impossible.

  In such a case, it is necessary to transmit push pulses at a plurality of positions in the azimuth direction. Specifically, the scanning region (or region of interest) is divided into a plurality of regions along the azimuth direction. The transmission / reception unit 11 transmits a push pulse at a different scanning line position to generate a shear wave before transmitting / receiving the tracking pulse 3a in each divided region. At this time, typically, the transmission position of the push pulse is set in the vicinity of each region. For example, the transmission / reception unit 11 refers to a table in which the distance from the left end of the region to be changed is set in advance. In addition, when the number of simultaneous parallel receptions is limited to a small number, the transmission / reception unit 11 performs a process of transmitting the tracking pulse 3a multiple times on each scanning line in a certain area in the azimuth direction after transmitting the push pulse once. Repeat for each of the multiple areas divided along.

  The image generation unit 14 generates ultrasonic image data from the data generated by the B mode processing unit 12 and the Doppler processing unit 13. That is, the image generation unit 14 generates two-dimensional B-mode image data in which the intensity of the reflected wave is expressed by luminance from the two-dimensional B-mode data generated by the B-mode processing unit 12. Further, the image generation unit 14 generates two-dimensional Doppler image data representing moving body information from the two-dimensional Doppler data generated by the Doppler processing unit 13. The two-dimensional Doppler image data is velocity image data, distributed image data, power image data, or image data obtained by combining these.

  Here, the image generation unit 14 generally converts (scan converts) a scanning line signal sequence of ultrasonic scanning into a scanning line signal sequence of a video format represented by a television or the like, and displays ultrasonic waves for display. Generate image data. Specifically, the image generation unit 14 generates ultrasonic image data for display by performing coordinate conversion in accordance with the ultrasonic scanning mode of the ultrasonic probe 1. In addition to the scan conversion, the image generation unit 14 performs various image processing, such as image processing (smoothing processing) for regenerating an average luminance image using a plurality of image frames after scan conversion, Image processing (edge enhancement processing) using a differential filter is performed in the image. Further, the image generation unit 14 synthesizes auxiliary information (character information of various parameters, scales, body marks, etc.) with the ultrasonic image data.

  That is, the B-mode data and Doppler data are ultrasonic image data before the scan conversion process, and the data generated by the image generation unit 14 is display ultrasonic image data after the scan conversion process. The B-mode data and the Doppler data are also called raw data (Raw Data).

  The image generation unit 14 generates hardness image data in which the hardness of the living tissue is displayed in color from the strain distribution information generated by the Doppler processing unit 13. FIG. 3 is an explanatory diagram illustrating an example of hardness image data generated by the image generation unit 14. As illustrated in FIG. 3, the image generation unit 14 causes the monitor 2 to display an image in which the hardness of the living tissue is classified according to a display mode such as a color or a shaded state.

  The image memory 15 is a memory for storing image data for display generated by the image generation unit 14. The image memory 15 can also store data generated by the B-mode processing unit 12 and the Doppler processing unit 13. The B-mode data and Doppler data stored in the image memory 15 can be called by an operator after diagnosis, for example, and become ultrasonic image data for display via the image generation unit 14.

  The internal storage unit 16 stores a control program for performing ultrasonic transmission / reception, image processing and display processing, diagnostic information (for example, patient ID, doctor's findings, etc.), various data such as a diagnostic protocol and various body marks. To do. The internal storage unit 16 is also used for storing image data stored in the image memory 15 as necessary. The data stored in the internal storage unit 16 can be transferred to an external device.

  The control unit 17 controls the entire processing of the ultrasonic diagnostic apparatus. Specifically, the control unit 17 is based on various setting requests input from the operator via the input unit 3 and various control programs and various data read from the internal storage unit 16. The processing of the processing unit 12, the Doppler processing unit 13, and the image generation unit 14 is controlled. Further, the control unit 17 controls the display 2 to display the display image data stored in the image memory 15 or the internal storage unit 16. In addition, the control unit 17 performs control so that the display image data generated by the image generation unit 14 is stored in the internal storage unit 16 or the like. The control unit 17 receives medical image data received from the operator via the input unit 3 from an external device via a network such as a LAN (Local Area Network) and an interface unit (both not shown). And control to be transferred to the image generation unit 14.

  The overall configuration of the ultrasonic diagnostic apparatus according to the first embodiment has been described above. With this configuration, the ultrasonic diagnostic apparatus according to the first embodiment visualizes the hardness of the living tissue by elastography.

  FIG. 4 is a flowchart illustrating an example of the operation of the ultrasonic diagnostic apparatus according to the first embodiment. Specifically, it is a processing procedure executed in an elast mode in which the hardness of a living tissue is visualized by elastography under the control of the control unit 17, and an ultrasonic diagnosis is performed by operating the input unit 3 by an operator. It is a flowchart which shows the process sequence after the operation mode of an apparatus was switched to the elast mode.

  As shown in FIG. 4, when the processing is started, the control unit 17 causes the transmission / reception unit 11 to transmit and receive B-mode pulses in order to display the B-mode image on the monitor 2 in substantially real time (S11). . Thereby, the B mode image generated by transmitting and receiving the B mode pulse is displayed on the monitor 2 in substantially real time. The operator can confirm the B-mode image of the subject P in substantially real time by confirming the display on the monitor 2.

  Next, the control unit 17 determines whether or not the input unit 3 has received a setting request for performing various settings related to the elast mode (S12). When the setting request has not been received (S12: NO), the control unit 17 advances the processing to S18, and determines whether or not the display request for the hardness image has been received by the input unit 3 (S18). Specifically, in S <b> 12 and S <b> 18, the control unit 17 determines whether an operation for starting various settings or an operation for displaying a hardness image has been performed on the input unit 3.

  When the display request for the hardness image is not received (S18: NO), the control unit 17 returns the process to S11. Thereby, in the elast mode, while the setting request for performing various settings or the display request for the hardness image is not received, the display of the B mode image in substantially real time is continued.

  When the setting request is received (S12: YES), the control unit 17 causes the monitor 2 to display a setting GUI for performing various settings related to the elast mode (S13). FIG. 5 is an explanatory diagram showing an example of the display screen 50 of the monitor 2. Specifically, it is a diagram illustrating a display screen 50 of the monitor 2 that displays a setting GUI.

  As shown in FIG. 5, the display screen 50 includes a B-mode image 51 scanned by the ultrasonic probe 1 as a GUI for performing various settings related to the elast mode. On the B-mode image 51, an ROI 52 for measuring the hardness of the living tissue is superimposed and displayed. Thereby, the operator can confirm the ROI 52 while referring to the B-mode image 51.

  Initial values of the size and position of the ROI 52 are stored in advance in the internal storage unit 16 or the like. The control unit 17 receives from the input unit 3 an instruction to change the size and position of the ROI 52 from the operator, and appropriately changes the size and position of the ROI 52 according to the received instruction.

  In addition, the display screen 50 includes a setting receiving unit 61 that receives setting of an index value related to the strength of the push pulse, and whether or not continuous display is performed to continuously generate and display a hardness image with a predetermined interval time. A setting receiving unit 62 that receives settings and a button 63 that receives setting completion (end).

  The setting receiving unit 61 receives an index value relating to the strength of the push pulse, that is, an index value indicating a mechanical impact of the push pulse on the subject P, by operating a rotary switch or a keypad of the input unit 3. Specifically, the setting reception unit 61 receives the value of the mechanical index (MI) of the push pulse. The index value of the mechanical impact that the push pulse exerts on the subject P includes the mechanical index, the drive voltage value of the ultrasonic probe 1 that is applied to transmit the push pulse, and the ultrasonic probe 1 that is applied to transmit the push pulse. It may be the amplitude value of the drive current.

  The operator adjusts the strength of the push pulse according to the subject P by appropriately setting the index value in the setting receiving unit 61. For example, for the subject P with thick subcutaneous fat, an index value for strengthening the push pulse is set in order to sufficiently generate the shear wave 2b necessary for measuring the propagation velocity in the ROI 52. For the subject P with thin subcutaneous fat, an index value for weakening the push pulse is set so that a mechanical shock more than necessary for generating the shear wave 2b in the ROI 52 is not applied.

  The setting accepting unit 62 accepts the presence / absence of continuous display by specifying the presence / absence of a check in a check box by a switch operation or cursor operation of the input unit 3. Further, in the GUI on the display screen 50, an index value (TI: thermal index) for the thermal action of the ultrasonic wave from the ultrasonic probe 1 on the living tissue, the surface temperature of the ultrasonic probe 1, the B-mode pulse and the tracking pulse You may receive the setting of the intensity | strength (acoustic power) of the ultrasonic wave concerning visualization of biological tissues, such as 3a.

  After displaying the GUI for performing various settings related to the elast mode on the monitor 2, the control unit 17 receives the setting of the ROI 52 and the index value related to the strength of the push pulse by the operation of the input unit 3 (S14). . Next, the control unit 17 sets the scanning width of the tracking pulse 3a and the number of divisions of the ROI 52 in the scanning width based on the ROI 52 and the index value relating to the strength of the push pulse set in S14 ( S15).

  The scanning width of the tracking pulse 3a depends on the mechanical impact of the push pulse on the subject P. Specifically, the displacement generated at the focal position 2a of the subject P by the push pulse is generally a minute amount of several to several tens of micrometers, and becomes smaller as the strength of the push pulse is smaller. Further, since the shear wave 2b generated by the displacement by the push pulse is attenuated in the process of propagation, it can be observed only about several millimeters in the living tissue. The sensitivity in the lateral direction of the shear wave 2b decreases as the push pulse intensity, that is, the displacement decreases. Therefore, the range in which the shear wave 2b can be observed, that is, the scanning width of the tracking pulse 3a becomes narrower as the push pulse intensity is smaller. Based on the correlation between the intensity of the push pulse and the scanning width of the tracking pulse 3a, the control unit 17 sets the scanning width of the tracking pulse 3a from the index value related to the strength of the push pulse.

  When the ROI 52 is wider than the set scanning width of the tracking pulse 3a, the entire ROI 52 cannot be covered even if the push pulse is transmitted to one place and scanned with the tracking pulse 3a. Therefore, when the ROI 52 is wide, push pulses are transmitted to a plurality of locations, and the focal position 2a generated at each location is scanned with the tracking pulse 3a. Then, by combining a plurality of hardness images obtained with the scanning width of the tracking pulse 3a, a hardness image of the entire ROI 52 is obtained.

  Therefore, the control unit 17 sets the division number to 0 when the set scanning width of the tracking pulse 3 a is equal to or larger than the width of the ROI 52. Further, when the width of the ROI 52 is wider than the set scanning width of the tracking pulse 3a, the control unit 17 converts the ROI 52 into the tracking pulse 3a based on the relationship between the scanning width of the tracking pulse 3a and the width of the ROI 52. The number of divisions for dividing into small areas (divided ROIs) less than or equal to the scanning width is set. Specifically, the number of divisions when the ROI 52 is divided by the set scanning width of the tracking pulse 3a (there may be overlap with a predetermined width) is calculated and set.

  At this time, the position of each divided ROI may also be calculated and set based on the position of the ROI 52, the set scanning width of the tracking pulse 3a, and the number of divisions of the ROI 52. Note that the position of each divided ROI can be uniquely determined in consideration of the overlap with a predetermined width if the position of the ROI 52, the number of divisions of the ROI 52, and the scanning width of the tracking pulse 3a are known. However, it may be calculated as necessary.

  Note that table data and relational expressions for obtaining the scanning width of the tracking pulse 3a and the number of divisions of the ROI 52 from the index values relating to the size of the ROI 52 and the strength of the push pulse are stored in advance in the internal storage unit 16 or the like. Good. In S15, the control unit 17 obtains the scanning width of the tracking pulse 3a and the number of divisions of the ROI 52 by referring to the table data and relational expressions stored in advance in the internal storage unit 16 based on the values received in S14. be able to.

  Next, based on the settings in S14 and S15, the control unit 17 updates the display of the monitor 2 so that the display screen 50 reflects the settings (S16). FIG. 6 is an explanatory diagram illustrating an example of the display screen 50 of the monitor 2. Specifically, the display screen 50 reflects the settings in S14 and S15.

  As shown in FIG. 6, the ROI 52 set in S <b> 14 is displayed on the display screen 50. Further, regarding the ROI 52, the divided ROIs 53, 54, and 55 are superimposed and displayed based on the ROI 52 set in S14 and the scanning width of the tracking pulse 3a set in S15 and the number of divisions of the ROI 52. Further, on the display screen 50, push pulse transmission positions 56, 57, and 58 corresponding to the divided ROIs 53, 54, and 55 are displayed.

  In general, the propagation speed of the shear wave 2b cannot be correctly obtained at the focal position 2a where the push pulse is transmitted at the push pulse transmission positions 56, 57, 58 and the displacement is generated in the living tissue. Therefore, push pulse transmission positions 56, 57, 58 are set at positions away from the divided ROIs 53, 54, 55. For example, an offset value that defines the distance from the divided ROIs 53, 54, and 55 is stored in the internal storage unit 16. The control unit 17 calculates positions that are separated from the left ends (or right ends) of the divided ROIs 53, 54, and 55 by an offset value as push pulse transmission positions 56, 57, and 58. Then, the control unit 17 displays the calculated push pulse transmission positions 56, 57, 58 on the display screen 50 of the monitor 2.

  Thus, the operator can make various settings related to the elast mode with reference to the ROI 52, the divided ROIs 53, 54, and 55 and the push pulse transmission positions 56, 57, and 58 on the display screen 50. Note that the ROI 52, the divided ROIs 53, 54, and 55 and the push pulse transmission positions 56, 57, and 58 are designated not only by a configuration in which all are combined and displayed as in the illustrated example, but also by an operation of the input unit 3, etc. It may be configured to display at least one item.

  Next, the control unit 17 determines whether or not to end the setting using the GUI based on whether or not the button 63 is operated (S17). When the setting is not ended (S17: NO), the control unit 17 returns the process to S13 and continues to display the setting GUI. When the setting is to be ended (S17: YES), the control unit 17 ends the display of the setting GUI (the process proceeds to S18).

  In S18, when a display request for the hardness image is received (YES), the control unit 17 determines whether or not various settings relating to the elast mode have been set (S19). If not set (S19: NO), the control unit 17 returns the process to S13 and accepts various settings for the elast mode. When it has been set (S19: YES), the control unit 17 starts the hardness image data generation process (S20).

  FIG. 7 is a flowchart illustrating an example of the hardness image data generation process. As shown in FIG. 7, when the hardness image data generation process is started, the control unit 17 sets a variable n corresponding to the divided ROIs 53, 54, and 55 to “n = 1” (S201).

  Next, under the control of the control unit 17, the transmission / reception unit 11 transmits a push pulse from the ultrasonic probe 1 with the intensity based on the index value set in S 14 at the push pulse transmission position in the nth divided ROI. (S202). Here, when the drive voltage value of the ultrasonic probe 1 or the amplitude value of the drive current of the ultrasonic probe 1 is set as the index value relating to the strength of the push pulse, the control unit 17 sets the set value. In use, push pulses are transmitted from the ultrasonic probe 1. Further, when a mechanical index value is set as an index value related to the strength of the push pulse, the control unit 17 uses the set value of the mechanical index as the driving voltage value of the ultrasonic probe 1 or the ultrasonic wave. It converts into the amplitude value of the drive current of the probe 1, and a push pulse is transmitted from the ultrasonic probe 1 using the converted value. Thereby, the push pulse for generating the shear wave 2b in the subject P is adjusted to the intensity corresponding to the index value set by the operator in S14 and transmitted.

  Next, under the control of the control unit 17, the transmission / reception unit 11 causes the ultrasonic probe 1 to perform transmission / reception of the tracking pulse 3a with the scanning width set in S15 in the nth divided ROI (S203). For example, the tracking pulse 3a is transmitted and received a plurality of times (about 100 times) with respect to a certain scanning line (raster) in the nth divided ROI. Thereby, the time change of the displacement at each point (each sample point) is calculated. If you have a system that can receive many pulses for one pulse, you can know the time change of displacement in the entire area in the ROI 52 by sending a single push pulse. Is limited, the tracking pulse 3a is transmitted and received a plurality of times by changing the raster position a plurality of times. In that case, a push pulse is transmitted every time the tracking pulse 3a is transmitted by changing the raster position.

  Subsequently, the Doppler processing unit 13 calculates a displacement at each point (each sample point) of the nth divided ROI, and generates strain distribution information (S204). Next, the image generation unit 14 generates hardness image data corresponding to the nth divided ROI based on the strain distribution information generated in S204 (S205).

  Next, the control unit 17 determines whether or not the variable n is the number of divisions (N) set in S15, that is, whether or not “n = N” (S206). When it is not “n = N” (S206: NO), the control unit 17 increments “n = n + 1” and “n” (S207), and returns the process to S202. If “n = N” (S206: YES), since the hardness image data is generated for all the divided ROIs in the ROI 52, the control unit 17 ends the hardness image data generation process.

  Returning to FIG. 4, the control unit 17 synthesizes the hardness image data generated for all the divided ROIs in the ROI 52 after the hardness image data generation process (S20). Next, the control unit 17 displays the hardness image data of the ROI 52 obtained by the synthesis on the monitor 2 (S21).

  As described above, in the first embodiment, the operator can adjust the strength of the push pulse according to the subject P by appropriately setting an index value indicating the mechanical impact on the subject P. it can.

(Second Embodiment)
Next, as a second embodiment, an operation in the case of performing continuous display in which the generation and display of the hardness image is continuously performed with a predetermined interval time is illustrated. FIG. 8 is a flowchart illustrating an example of the operation of the ultrasonic diagnostic apparatus according to the second embodiment.

  As illustrated in FIG. 8, when the setting reception unit 62 receives a setting for performing continuous display in the setting GUI, the control unit 17 indicates an index value related to the push pulse strength set in S14 after S15. Based on the above, an interval time for continuously generating and displaying the hardness image is set (S15a).

  It is necessary to suppress the acoustic power (average power) per unit time so that the acoustic power of the ultrasonic probe 1 is within the output regulation range such as power consumption restriction, thermal index, and surface temperature of the ultrasonic probe 1. There is. Therefore, in S15a, the ultrasonic probe 1 is set by setting an interval time for continuously generating and displaying the hardness image according to the strength of the push pulse corresponding to the index value set in S14. So that the average power is within the output regulation range.

  Specifically, the control unit 17 adds the acoustic power at the time of transmission of the push pulse corresponding to the index value set in S14 and the acoustic power at the time of transmission / reception of the tracking pulse 3a and the B mode pulse, An average power is obtained when continuous display is performed at a predetermined interval time. Next, when the obtained average power is equal to or greater than the output regulation range, the control unit 17 repeats the process of obtaining the average power again by increasing the interval time so that the average power is within the output regulation range. Thereby, even when the index value relating to the strength of the push pulse is set, the frame rate of the hardness image in the continuous display is adjusted so that the average power is within the output regulation range.

  In addition, when the calculated average power is within the output regulation range, the control unit 17 shortens the interval time and repeats the process of obtaining the average power again so that the average power approaches the upper limit of the output regulation range. May be. In this case, even when setting an index value related to the strength of the push pulse, the frame rate of the hardness image in continuous display can be shortened by bringing the average power closer to the upper limit of the output restriction range, and real-time characteristics are improved. It can be secured. Therefore, it is possible to improve the diagnostic performance of the living tissue by the hardness image.

  Following the display of hardness image data (S21) after receiving a hardness image display request (S18: YES), the control unit 17 determines whether or not an end operation has been received from the input unit 3. In step S22, it is determined whether to end the display. When the display is ended, the control unit 17 ends the process.

  When the display is not terminated, the control unit 17 determines whether or not the interval time set from the most recent hardness image data generation process (S20) has elapsed (S23). The measurement of the interval time is performed by an RTC (Real Time Clock) function in the control unit 17 or the like.

  When the interval time has elapsed (S23: YES), the control unit 17 returns the process to S20 and starts the hardness image data generation process. When the interval time has not elapsed (S23: NO), the control unit 17 causes the transmission / reception unit 11 to transmit and receive B-mode pulses to update the B-mode image on the monitor 2 (S24), and the process proceeds to S22. return. Thus, the generation and display of the hardness image is continuously performed with a set interval time.

  FIG. 9 is an explanatory diagram for explaining transmission / reception timings of the B-mode pulse, push pulse, and tracking pulse. As shown in FIG. 9, the B-mode pulse transmission / reception 71 is repeated in a period T1 up to time t1 when the display of the hardness image is requested. Next, in a period T2 from time t1 at which the hardness image display request is made to time t2 at which the hardness image data generation processing is completed, push pulse transmission 72 and tracking pulse transmission / reception 73 are repeated. The hardness image data generation process is paused during a period T3 (time t2 to t3) corresponding to the set interval time.

  This period T3 is a period adjusted according to the index value concerning the strength of the push pulse. In the period T3 during which the hardness image data generation process is suspended, the B-mode image may be updated by performing at least one B-mode pulse transmission / reception 71, and the B-mode pulse transmission / reception is performed as in the illustrated example. 71 may be repeated at predetermined time intervals.

  After the time t3 when the set interval time has elapsed from the time t2, the hardness image data generation process is started, and the push pulse transmission 72 and the tracking pulse transmission / reception 73 are repeated during the period T4 up to the time t4. This continues to the next period T5.

  As described above, in the second embodiment, even when the operator appropriately sets an index value indicating the mechanical impact on the subject P, the continuous display is performed so that the average power is within the output regulation range. The frame rate of the hardness image can be adjusted.

  In the second embodiment described above, the case where the generation and display of the hardness image is continuously performed with a predetermined interval time is exemplified, but the transmission of the push pulse is continuously performed with the predetermined interval time. It may be performed. Specifically, as with the adjustment of the frame rate of the hardness image, the interval time for transmitting the push pulse is set so that the average power falls within the output regulation range based on the index value for the strength of the push pulse. You may adjust.

  According to at least one embodiment described above, it is possible to adjust the intensity of ultrasonic waves for generating a shear wave in a subject.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit 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 equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Ultrasonic probe, 2 ... Monitor, 2a ... Focal position, 2b ... Shear wave, 3 ... Input part, 3a ... Tracking pulse, 10 ... Apparatus main body, 11 ... Transmission / reception part, 12 ... B mode processing part, 13 ... Doppler Processing unit, 14 ... Image generation unit, 15 ... Image memory, 16 ... Internal storage unit, 17 ... Control unit, 50 ... Display screen, 51 ... B-mode image, 52 ... ROI, 53-55 ... Split ROI, 56-58 ... Push pulse transmission position, 61, 62 ... Setting reception unit, 63 ... Button, 71 ... B mode pulse transmission / reception, 72 ... Push pulse transmission, 73 ... Tracking pulse transmission / reception, P ... Subject, t1 to t4 ... Time, T1 ~ T5 ... period

Claims (11)

A transmission / reception unit for transmitting a first ultrasonic wave for generating a shear wave in an object from an ultrasonic probe and transmitting / receiving a second ultrasonic wave for measuring a propagation speed of the shear wave by the ultrasonic probe; ,
A reception unit that receives setting of an index value related to transmission of the first ultrasonic wave;
Based on the set index value, the intensity of transmission of the first ultrasonic wave is controlled , and a scan width for transmitting and receiving the second ultrasonic wave with respect to the transmission of the first ultrasonic wave is set. A control unit for controlling according to the strength of the transmission ;
Equipped with a,
The reception unit receives a setting of a region of interest in the subject,
The control unit divides the set region of interest based on a scan width for transmitting and receiving the second ultrasonic wave, and transmits the first ultrasonic wave for each divided region of interest, An ultrasonic diagnostic apparatus that performs transmission and reception of the second ultrasonic wave with a scanning width . The index value is a value indicating a mechanical impact on the subject, the mechanical index of the first ultrasonic wave, the transmission drive voltage value of the first ultrasonic wave, and the transmission drive of the first ultrasonic wave. One of the current amplitude values,
The ultrasonic diagnostic apparatus according to claim 1. A display unit configured to display at least one of the set region of interest, each of the divided regions of interest, and the transmission position of the first ultrasonic wave corresponding to the divided region of interest; ,
The ultrasonic diagnostic apparatus according to claim 1 or 2 . In the case where the control unit continuously transmits the first ultrasonic wave at a predetermined interval time and generates the hardness image of the subject based on the measured propagation speed of the shear wave. Controlling the interval time based on the set index value;
The ultrasonic diagnostic apparatus as described in any one of Claims 1 thru | or 3. A transmission / reception unit for transmitting a first ultrasonic wave for generating a shear wave in an object from an ultrasonic probe and transmitting / receiving a second ultrasonic wave for measuring a propagation speed of the shear wave by the ultrasonic probe; ,
A reception unit that receives setting of an index value related to transmission of the first ultrasonic wave;
A control unit for controlling the intensity of transmission of the first ultrasonic wave based on the set index value;
With
In the case where the control unit continuously transmits the first ultrasonic wave at a predetermined interval time and generates the hardness image of the subject based on the measured propagation speed of the shear wave. An ultrasonic diagnostic apparatus that controls the interval time based on the set index value. The index value is a value indicating a mechanical impact on the subject, the mechanical index of the first ultrasonic wave, the transmission drive voltage value of the first ultrasonic wave, and the transmission drive of the first ultrasonic wave. One of the current amplitude values,
The ultrasonic diagnostic apparatus according to claim 5. The control unit controls transmission intensity of the first ultrasonic wave based on the set index value, and transmits and receives the second ultrasonic wave with respect to the transmission of the first ultrasonic wave. Controlling the scanning width according to the intensity of the transmission,
The ultrasonic diagnostic apparatus according to claim 5 or 6. The reception unit receives a setting of a region of interest in the subject,
The control unit divides the set region of interest based on a scan width for transmitting and receiving the second ultrasonic wave, and transmits the first ultrasonic wave for each divided region of interest, Causing the second ultrasonic wave to be transmitted and received at a scan width;
The ultrasonic diagnostic apparatus according to claim 7. A display unit configured to display at least one of the set region of interest, each of the divided regions of interest, and the transmission position of the first ultrasonic wave corresponding to the divided region of interest; ,
The ultrasonic diagnostic apparatus according to claim 8. On the computer,
Accept the setting of the index value and the region of interest in the subject ,
Based on the set index value, the first ultrasonic wave for generating a shear wave in the subject is transmitted from the ultrasonic probe, and the second ultrasonic wave for measuring the propagation speed of the shear wave A scanning width for controlling the intensity of transmission of the first ultrasonic wave when transmitting and receiving the ultrasonic wave with the ultrasonic probe and transmitting and receiving the second ultrasonic wave with respect to the transmission of the first ultrasonic wave Is controlled according to the intensity of the transmission, and the set region of interest is divided based on a scan width for transmitting and receiving the second ultrasonic wave, and the first region is divided for each of the divided regions of interest. Causing transmission of ultrasonic waves and transmission / reception of the second ultrasonic waves at the scanning width;
A control program that executes each process. On the computer,
Accept index value settings,
Based on the set index value, a first ultrasonic wave for generating a shear wave in the subject is continuously transmitted from the ultrasonic probe at a predetermined interval time, and the propagation speed of the shear wave is measured. For controlling the intensity of transmission of the first ultrasonic wave when transmitting and receiving the second ultrasonic wave for transmission by the ultrasonic probe, and based on the measured propagation velocity of the shear wave. When generating an image, the interval time is controlled based on the set index value.
A control program that executes each process.