WO2011001776A1 - Ultrasonic diagnostic equipment, and shear wave propagation image generating method - Google Patents

Ultrasonic diagnostic equipment, and shear wave propagation image generating method Download PDF

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Publication number
WO2011001776A1
WO2011001776A1 PCT/JP2010/059240 JP2010059240W WO2011001776A1 WO 2011001776 A1 WO2011001776 A1 WO 2011001776A1 JP 2010059240 W JP2010059240 W JP 2010059240W WO 2011001776 A1 WO2011001776 A1 WO 2011001776A1
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WIPO (PCT)
Prior art keywords
image
shear wave
ultrasonic
unit
propagation
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PCT/JP2010/059240
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French (fr)
Japanese (ja)
Inventor
卓司 大坂
毅 三竹
直之 村山
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株式会社 日立メディコ
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Priority to JP2011520841A priority Critical patent/JPWO2011001776A1/en
Publication of WO2011001776A1 publication Critical patent/WO2011001776A1/en

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B8/00—Diagnosis using ultrasonic, sonic or infrasonic waves
    • A61B8/08—Detecting organic movements or changes, e.g. tumours, cysts, swellings
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B8/00—Diagnosis using ultrasonic, sonic or infrasonic waves
    • A61B8/48—Diagnostic techniques
    • A61B8/485—Diagnostic techniques involving measuring strain or elastic properties
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/52—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S15/00
    • G01S7/52017—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S15/00 particularly adapted to short-range imaging
    • G01S7/52023—Details of receivers
    • G01S7/52036—Details of receivers using analysis of echo signal for target characterisation
    • G01S7/52042—Details of receivers using analysis of echo signal for target characterisation determining elastic properties of the propagation medium or of the reflective target
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/52—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S15/00
    • G01S7/52017—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S15/00 particularly adapted to short-range imaging
    • G01S7/52053—Display arrangements
    • G01S7/52057—Cathode ray tube displays
    • G01S7/52071—Multicolour displays; using colour coding; Optimising colour or information content in displays, e.g. parametric imaging
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/52—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S15/00
    • G01S7/52017—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S15/00 particularly adapted to short-range imaging
    • G01S7/52053—Display arrangements
    • G01S7/52057—Cathode ray tube displays
    • G01S7/52074—Composite displays, e.g. split-screen displays; Combination of multiple images or of images and alphanumeric tabular information

Definitions

  • the present invention relates to an ultrasonic diagnostic apparatus that obtains and displays elasticity information of a living tissue or the like using ultrasonic waves, and a shear wave propagation image generation method.
  • the ultrasonic diagnostic apparatus transmits an ultrasonic wave to a biological tissue or the like by an ultrasonic probe, receives an ultrasonic reflected echo signal corresponding to the structure of the biological tissue or the like, and generates and displays an ultrasonic tomographic image.
  • the biological tissue or the like is compressed with an ultrasonic probe using a technique or a mechanical method, and the displacement of the biological tissue is obtained based on the frame data of two ultrasonic signals having different measurement times, and the biological tissue is obtained from the displacement data. It is possible to generate an elasticity image showing elasticity information on the hardness or softness of the image.
  • a method for obtaining elasticity information using ultrasonic waves there is a method using a wave called a shear wave generated by a low frequency (about 1 kHz) vibration applied to a living body or the like. Since the propagation speed of the shear wave indicates the hardness of the propagation medium and is proportional to the square root of the shear elastic modulus, the elasticity information of the living tissue can be obtained by measuring the propagation speed of the shear wave using ultrasonic waves. Examples of such techniques include Patent Documents 1 and 2.
  • Patent Document 1 a dedicated probe for measuring the propagation speed of shear waves is used.
  • a tomographic image of the subject cannot be acquired with this probe alone.
  • the shear wave propagation velocity cannot be measured.
  • Patent Documents 1 and 2 also describe that a dedicated probe for measuring the propagation speed of shear waves is attached to a probe for tomographic image acquisition, but two probes are required, and tomographic image acquisition is also required. Since two ultrasonic transmission / reception units are required for measuring the propagation speed of shear waves and shear waves, the operation and configuration become complicated.
  • the problem to be solved by the present invention is to provide an ultrasonic diagnostic apparatus and a shear wave propagation image generation method capable of acquiring tomographic images with one ultrasonic probe and acquiring elastic information by shear waves.
  • an ultrasonic diagnostic apparatus of the present invention includes an ultrasonic probe that transmits and receives ultrasonic waves to and from a subject, a vibrator that generates shear waves in the subject, and the ultrasonic probe.
  • An ultrasonic diagnostic apparatus comprising: a transmission / reception unit that performs transmission and reception processing of the ultrasonic wave between; and a tomographic image configuration unit that forms a tomographic image based on the reflected echo signal received and processed by the transmission / reception unit.
  • the transmission / reception unit transmits / receives the ultrasonic wave to / from the subject at a time interval and obtains shear wave propagation information based on the transmission / reception, and the obtained shear wave
  • a shear wave image constituting unit that constitutes a shear wave image representing the propagation information of the image
  • an image display unit that displays the shear wave image and the tomographic image.
  • scanning is performed while transmitting and receiving ultrasonic waves for acquiring tomographic images using the same ultrasonic probe, while transmission and reception of ultrasonic waves for acquiring tomographic images is paused at set time intervals,
  • shear wave propagation information can be acquired while acquiring a tomographic image. Accordingly, the propagation information of the shear wave can be acquired together with the tomographic image without the two probes of the probe for acquiring the tomographic image and the probe for measuring the propagation speed of the shear wave.
  • the shear wave propagation information includes the shear wave propagation position and propagation time, and the shear wave propagation speed can be obtained from these relationships.
  • the propagation position of the shear wave is obtained from the time until the ultrasonic wave for detecting the propagation position is reflected back to the shear wave and the velocity of the ultrasonic wave. Thereby, the elasticity information of the hardness or softness of the living tissue can be acquired.
  • ultrasonic transmission / reception units for tomographic image acquisition and shear wave propagation position detection can be provided, respectively, or one can be shared. In order to accurately obtain the relationship between the propagation position of the shear wave and the propagation time, it is desirable to transmit and receive as many ultrasonic waves for detecting the propagation position as possible in one frame.
  • a direction setting unit that sets a direction for transmitting and receiving ultrasonic waves for detecting a propagation position with respect to the subject is provided, and the direction setting unit has a direction (setting direction) on the tomographic image displayed on the image display unit. It can also comprise so that the measurement line production
  • the propagation image construction unit can construct a shear wave image based on the depth of the shear wave with respect to the subject and the elapsed time from the generation of the shear wave.
  • the propagation image forming unit can be configured to display a shear wave image corresponding to a region selected on the tomographic image displayed on the image display unit on the image display unit.
  • region corresponding to a tomographic image can be confirmed easily, and usability improves.
  • the ultrasonic diagnostic apparatus can be provided with an elastic information calculation unit for calculating an elastic modulus distribution based on the shear wave image.
  • the image display unit can be configured to display the combined elastic modulus distribution in association with the tomographic image. This makes it easy to confirm the elastic modulus distribution on the tomographic image, and improves usability.
  • an M mode image configuration unit that configures an M mode image based on the reflected echo signal received and processed by the transmission / reception unit is provided, and the tomographic image, the shear wave image, and the M mode image are displayed side by side on the image display unit. It can also be configured as follows. Furthermore, the transmission / reception unit may be configured to detect the change on the M-mode image and start transmitting the ultrasonic wave for detecting the propagation position.
  • an elastic image constructing unit that generates RF frame data by receiving and processing a reflected echo signal in the process of applying pressure to the subject via an ultrasonic probe, and an elastic image and a shear wave image are juxtaposed instead of the tomographic image
  • a display selection unit that selects either a display method for displaying the image, or a display method for displaying the elastic image, the shear wave image, and the tomographic image in parallel, and the image display unit is selected. It is also possible to configure to display an image of a different display method.
  • ultrasonic waves are transmitted to and received from an object using an ultrasonic probe, shear waves are generated in the object provided on the ultrasonic probe by a vibrating body, and transmitted and received.
  • the ultrasonic transmission and reception processing is performed with the ultrasonic probe by the unit, the tomographic image is configured based on the reflected echo signal received and processed by the transmission and reception unit by the tomographic image configuration unit, and the propagation position is detected by the transmission and reception unit.
  • the first step includes a step of setting a direction for transmitting and receiving ultrasonic waves for detecting a propagation position of shear waves to the subject by the direction setting unit, and a tomographic image displayed on the image display unit by the direction setting unit. And a step of generating a measurement line indicating a direction by the measurement line generation unit, and the third step is performed on the tomographic image displayed on the image display unit by the propagation image configuration unit. It can also be configured to include a step of constructing a shear wave image based on the selected region.
  • the fourth step is a step of calculating an elastic modulus distribution based on the shear wave image by the elastic information calculating unit, and combining and displaying the elastic modulus distribution in association with the tomographic image on the image display unit, and an M mode.
  • a step of constructing an M mode image based on the reflected echo signal received and processed by the transmission / reception unit by the image construction unit, and a step of juxtaposing and displaying the M mode image, the tomographic image, and the shear wave image on the image display unit It can also be configured to include.
  • the reflected image signal in the process of applying pressure to the subject via the ultrasonic probe by the elastic image forming unit is received to generate RF frame data, and the elastic image is generated from the RF frame data.
  • a display method in which an elastic image and a shear wave image are displayed side by side instead of a tomographic image by a display step, or a display method in which an elastic image, a shear wave image, and a tomographic image are displayed in parallel It is also possible to include a step of selecting any one of the display methods and a step of displaying an image of the selected display method on the image display unit.
  • an ultrasonic diagnostic apparatus capable of acquiring a tomographic image with one ultrasonic probe and acquiring elastic information by shear waves.
  • Configuration diagram of the ultrasonic diagnostic apparatus of the present invention (a) shows the configuration of the ultrasonic probe, and (b) shows the state of the ultrasonic wave transmitted from the ultrasonic probe.
  • Ultrasonic transmission timing chart Diagram showing the relationship between shear wave depth and time Example of shear wave image displayed on image display Screen displaying B-mode image, M-mode image, and shear wave image Screen with elasticity information displayed on the B-mode image Flow chart until acquiring elastic information by shear wave
  • the ultrasonic diagnostic apparatus of the present embodiment includes an ultrasonic probe 4 that transmits and receives ultrasonic waves to and from a subject 5, and a mechanism that can be attached to and detached from the ultrasonic probe 4.
  • a vibrating body 3 that generates a shear wave by applying a low-frequency vibration to the subject 5 via the probe 4 and a transmitter that repeatedly transmits ultrasonic waves to the subject 5 via the ultrasonic probe 4 at time intervals.
  • a receiving unit 6 that receives a time-series reflected echo signal generated from the subject 5
  • an ultrasonic transmission / reception control unit 1 that controls the transmitting unit 2 and the receiving unit 6, and a reflected echo received by the receiving unit 6
  • a phasing adder 7 for phasing and adding signals.
  • the tomographic image constructing unit 8 constituting the tomographic image of the subject 5, for example, a black and white tomographic image, and the output signal of the tomographic image constructing unit 8 And a black and white scan converter 9 for converting the image display unit 18 so as to match the display.
  • RF Radio Frequency
  • the frame data memory 10a that stores the RF frame signal output from the phasing addition unit 7, the displacement measurement unit 10 that measures the displacement generated in the living tissue of the subject 5, and the displacement measurement unit 10
  • Elasticity information calculation unit 11 for obtaining strain or elastic modulus for calculating elasticity information in a continuous compression process from displacement information, and an elastic image constituting a color elasticity image from the strain or elastic modulus calculated by the elasticity information calculation unit 11
  • a configuration unit 12 and a color scan converter 13 that converts the output signal of the elastic image configuration unit 12 to match the display of the image display unit 18 are provided.
  • the line data memory 14a for storing an RF line signal, which will be described in detail later, outputted from the phasing adder 7, and the direction in which the ultrasonic wave 21 for detecting the propagation position of the shear wave is transmitted to and received from the subject 5 are transmitted.
  • Direction setting unit 14b for setting, shear wave propagation position detection unit 14 for obtaining propagation information of shear wave, and shear wave for obtaining Young's modulus for calculating elastic information from propagation information obtained by shear wave propagation position detection unit 14
  • An elastic information calculation unit 15 and a shear wave image construction unit 16 that generates an image based on the time axis from the propagation information obtained by the shear wave propagation position detection unit 14 are provided. Note that the output signal of the shear wave image constructing unit 16 is converted by the color scan converter 13 so as to match the display of the image display unit 18.
  • a switching addition unit 17 that superimposes a monochrome tomographic image and a color elastic image, displays them in parallel, or switches them, an image display unit 18 that displays a synthesized composite image, and The console 19 is provided.
  • the ultrasonic probe 4 is formed by arranging a plurality of transducers, and has a function of transmitting and receiving ultrasonic waves to and from the subject 5 via the transducers.
  • the transmission unit 2 generates a transmission pulse for generating an ultrasonic wave by driving the ultrasonic probe 4, and has a function of setting a convergence point of the transmitted ultrasonic wave to a certain depth.
  • the receiving unit 6 amplifies the reflected echo signal received by the ultrasonic probe 4 with a predetermined gain to generate an RF signal, that is, a received signal.
  • the phasing / adding unit 7 inputs the RF signal amplified by the receiving unit 6 and performs phase control, and forms an ultrasonic beam at one point or a plurality of convergence points to generate an RF frame signal.
  • the tomographic image construction unit 8 receives the RF frame signal from the phasing addition unit 7 and performs signal processing such as gain correction, log compression, detection, contour enhancement, filter processing, and so forth, such as a B-mode image and an M-mode image. The tomographic image data is obtained.
  • the black-and-white scan converter 9 includes an analog / digital converter (not shown) that converts tomographic image data from the tomographic image construction unit 8 into a digital signal, a frame memory that stores a plurality of converted tomographic image data in time series, a control controller, It is comprised including.
  • the black-and-white scan converter 9 acquires tomographic frame data in the subject 5 stored in the frame memory as one image, and reads the acquired framed frame data in synchronization with the television.
  • the RF frame signal output from the phasing adder 7 is appropriately selected and recorded in the frame data memory 10a.
  • the displacement measurement unit 10 performs one-dimensional or two-dimensional correlation processing from one set of data in the frame data memory 10a, and performs displacement and movement vectors in the biological tissue corresponding to each point of the tomographic image, that is, the direction and magnitude of the displacement. Find the one-dimensional or two-dimensional displacement distribution on the height.
  • the movement vector detection method is a block matching method.
  • the block matching method divides an image into blocks of N ⁇ N pixels, for example, pays attention to the block in the region of interest, searches the previous frame for the block that is closest to the block of interest, and refers to this Thus, predictive encoding, that is, processing for determining the sample value by the difference is performed.
  • the elasticity information calculation unit 11 calculates strain or elastic modulus for the data output from the displacement measurement unit 10. For example, when calculating the elastic modulus, a pressure value measured by a pressure sensor (not shown) connected to the ultrasonic probe 4 can be used, but strain data is calculated from output data from the displacement measuring unit 10. There is a need. This strain data is calculated by spatially differentiating the movement amount of the living tissue, for example, the displacement. The elastic modulus data is calculated by dividing the change in pressure by the change in strain.
  • the Young's modulus is a ratio of a simple tensile stress applied to an object and a strain generated in parallel to the tension.
  • the elastic image construction unit 12 includes a frame memory (not shown) and an image processing unit, and secures the elastic frame data output in time series from the elastic information calculation unit 11 in the frame memory. On the other hand, desired image processing is performed.
  • the color scan converter 13 has a function of adding hue information to elastic image data from the elastic image construction unit 12 and a shear wave image construction unit 16 described later.
  • the light is converted into three primary colors, that is, red (R), green (G), and blue (B).
  • R red
  • G green
  • B blue
  • elastic data having a large strain is converted into a red code
  • elastic data having a small strain is converted into a blue code.
  • the configuration that is a feature of the present embodiment is, in particular, between the ultrasonic probe 4 that transmits and receives ultrasonic waves to and from the subject 5, the vibrator 3 that generates shear waves in the subject 5, and the ultrasonic probe 4.
  • Transmission / reception units 2 and 6 that perform transmission and reception processing of ultrasonic waves, and a tomographic image configuration unit 8 that forms a tomographic image based on the reflected echo signals received and processed by the transmission / reception units 2 and 6
  • a diagnostic apparatus wherein transmission / reception units 2 and 6 transmit and receive ultrasonic waves to and from a subject 5 at time intervals, and obtain shear wave propagation information based on the transmission and reception, and a shear wave propagation position detection unit 14
  • a shear wave image constructing unit 16 that constitutes a shear wave image representing the obtained shear wave propagation information, and an image display unit 18 that displays the shear wave image and the tomographic image are provided.
  • the detachable vibrator 3 is attached to the ultrasonic probe 4.
  • the vibration emitted from the vibrating body 3 may be either continuous or single vibration.
  • the ultrasonic wave irradiated to the subject 5 from the transmitting unit 2 via the ultrasonic probe 4 includes the ultrasonic wave 20 for tomographic image acquisition and the propagation position of the shear wave.
  • the ultrasonic wave 20 for tomographic image acquisition is to transmit a plurality of transducers arranged in the ultrasonic probe 4 by sequentially switching them.
  • the transmission direction of the ultrasonic wave 21 for detecting the propagation position of the shear wave is determined in advance. In the present embodiment, it is the depth direction of the subject 5.
  • the ultrasonic wave 21 for detecting the propagation position is transmitted only from a portion set in advance as a channel among a plurality of transducers arranged in the ultrasonic probe 4.
  • the transducer in the middle of the ultrasonic probe 4 is set as a channel.
  • FIG. 3 shows a transmission timing chart of the ultrasonic wave 20 for tomographic image acquisition and the ultrasonic wave 21 for propagation position detection.
  • the ultrasonic wave 21 for detecting the propagation position is transmitted once every time a plurality of ultrasonic waves 20 for acquiring the tomographic image are transmitted, and the transmission interval is ⁇ .
  • PRF pulse repetition frequency
  • the reception signal of the ultrasonic wave 21 for detecting the propagation position transmitted in this way is sequentially recorded in the line data memory 14a.
  • This received signal is a signal affected by the shear wave when the ultrasonic wave 21 for detecting the propagation position is reflected by the shear wave.
  • the shear wave propagation position detector 14 obtains shear wave propagation information from a plurality of received signals.
  • the shear wave propagation information includes the shear wave propagation position and propagation time. The propagation position of the shear wave is obtained from the time until the ultrasonic wave 21 for detecting the propagation position is reflected back to the shear wave and the velocity of the ultrasonic wave.
  • Fig. 4 shows a graph showing the relationship between the depth (vertical axis) and the time (horizontal axis), which are the shear wave positions.
  • the rectangles in FIG. 4 are displacements generated along with the propagation of the shear wave.
  • the width of the rectangle in the vertical direction of the paper corresponds to the wave number of the shear wave, and the width in the horizontal direction of the paper corresponds to the amplitude.
  • the shear wave propagates to the inside of the subject 5 with the passage of time, but the propagation speed can be calculated by the depth and time (reciprocal of ⁇ ) obtained by the ultrasonic wave 21 for detecting the propagation position. .
  • the shear wave image construction unit 16 generates a shear wave image from the shear wave propagation information in the depth direction obtained by the shear wave propagation position detection unit 14 and a graph of the elasticity information by the shear wave obtained by the shear wave elasticity information calculation unit 15.
  • Configure and color scan converter 13 images it.
  • FIGS. 5A and 5B show examples of shear wave images.
  • the vertical axis represents depth (upper side is 0) and the horizontal axis represents time, and the slope represents the propagation speed. Since the propagation speed increases as the medium becomes harder, FIG. 5 (a) shows that the medium is harder than in FIG. 5 (b).
  • the elastic information graph based on shear waves has a Young's modulus on the vertical axis and a depth on the horizontal axis, and is shown on the B-mode image in FIG. 7 in the present embodiment.
  • the switching addition unit 17 includes a frame memory (not shown), an image processing unit, and an image selection unit (display selection unit).
  • the frame memory stores the tomographic image data from the monochrome scan converter 9 and the elastic image data from the color scan converter 13, and the tomographic image data and the elastic image data (the image of the propagation velocity distribution) are stored by the image processing means.
  • the image processing means are also synthesized at different synthesis ratios.
  • the luminance information and hue information of each pixel of the composite image is obtained by adding each information of the black and white tomographic image and the color elastic image at the composite ratio. Further, the image selection means selects an image to be displayed on the image display unit 18 from the tomographic image data and elasticity image data in the frame memory and the composite image data of the image processing unit.
  • FIG. 6 shows an example of a screen displayed on the image display unit 18.
  • FIG. 6 shows a state in which three types of images, a B-mode image, an M-mode image, and a shear wave image are drawn.
  • a B-mode image is displayed in real time, and a measurement line 22 indicating a position for obtaining a shear wave image is displayed on the B-mode image.
  • the inspector can freely change the position of the measurement line 22 by issuing a command to the direction setting unit 14b using the console 19.
  • a channel for transmitting the ultrasonic wave 21 for detecting the propagation position is determined.
  • the M mode image in the measurement line 22 is shown, and in the lower right half of FIG. 6, the propagation velocity distribution image in the measurement line 22 is shown as a semitransparent display.
  • the inspector conducts the inspection while confirming the B-mode image depicted in the left half of Fig. 6, and determines the cross section for which the shear wave image is to be obtained.
  • a measurement line 22 is set for the determined cross section (FIG. 6 shows a case where the measurement line is set at the center).
  • the vibrating body 3 attached to the ultrasonic probe 4 is manually operated to apply a low frequency vibration to the subject 5 to generate a shear wave, and a shear wave image is obtained as described above.
  • FIG. 7 is a screen in which the elasticity information obtained by the shear wave elasticity information calculation unit 15 is synthesized and displayed on the measurement line 22 of the B-mode image in FIG. As a result, the elasticity information can be confirmed on the B-mode image, which improves usability.
  • Fig. 8 shows a flowchart for acquiring elasticity information by shear waves.
  • a step of transmitting and receiving ultrasonic waves to and from the subject 5 by the ultrasonic probe 4, a step of generating a shear wave in the subject 5, a step of obtaining shear wave propagation information, and a shear representing the propagation information of the shear wave A step of constructing a wave image, and a step of displaying the shear wave image and the tomographic image in association with each other on the image display unit 18.
  • the inspector performs ultrasonic diagnosis using the B-mode image, and at the same time, determines a cross section for acquiring elastic information by shear waves using the measurement line 22 (step 1).
  • the examiner applies vibration to the subject 5 by operating the vibrating body 3 attached to the ultrasonic probe 4 (step 2).
  • the ultrasonic wave 21 for detecting the propagation position of the shear wave is transmitted from the transmission unit 2 a plurality of times at time intervals toward the cross section set by the measurement line 22 (step 3).
  • the shear wave propagation position detection unit 14 obtains the shear wave propagation position and the shear wave propagation time based on the transmission and reception in Step 3 (Step 4).
  • the shear wave image constructing unit 16 constructs a shear wave image representing the relationship between the propagation position and propagation time of the shear wave obtained in Step 4 (Step 5).
  • the tomographic image construction unit 8 constructs an M-mode image based on the reflected echo signal received and processed by the transmission / reception unit (step 6).
  • the shear wave image configured in step 5 and the B mode image are displayed in association with each other, and the M mode image configured in step 6 is juxtaposed (step 7).
  • the elastic modulus distribution on the measurement line is calculated based on the shear wave image by the shear wave elastic information calculation unit 15, and the B mode image displayed on the image display unit 18 is combined with the elastic modulus distribution and displayed. (Step 8).
  • scanning is performed while transmitting and receiving the ultrasonic wave 20 for tomographic image acquisition using the same ultrasonic probe 4, while transmission and reception of the ultrasonic wave 20 for acquiring the tomographic image is set.
  • the propagation position of the shear wave is detected while acquiring the tomographic image be able to. Accordingly, the relationship between the propagation position of the shear wave and the propagation time in the setting direction can be acquired together with the tomographic image, even without the probe for tomographic image acquisition and the probe for measuring the propagation speed of the shear wave. From the relationship between the propagation position of the shear wave and the propagation time, the propagation speed of the shear wave can be obtained, whereby the elasticity information of the hardness or softness of the biological tissue in the set direction can be acquired.
  • the direction setting unit 14b is configured to include a measurement line generation unit that generates the measurement line 22 indicating the setting direction on the B mode image of FIG. 6 displayed on the image display unit 18, the shear wave image The line you want to get can be determined by referring to the B-mode image.
  • the image display unit 18 is configured to display the composite elastic modulus distribution obtained by the shear wave elastic information calculation unit 15 in association with the B mode image, the elastic modulus distribution is confirmed on the B mode image. Easier to use, and easier to use.
  • the present invention is not limited to this, and can be applied by appropriately changing the configuration.
  • the inspector uses the console 19 to display the elastic image, the shear wave image, and the M mode image side by side instead of the B mode image in FIG.
  • Any display method of displaying elastic images, shear wave images, B-mode images, and M-mode images side by side can be selected, and the selection step can be added to the flowchart of FIG.
  • a display method using only a B-mode image and a shear wave image can be configured.
  • the ultrasonic wave 21 for detecting the propagation position is transmitted at the time of acquiring the B-mode image regardless of whether or not a shear wave is generated. Since a change occurs on the mode image, the ultrasonic wave 21 for detecting the propagation position may be transmitted when this change is detected.
  • the shear wave image construction unit 16 can be configured to display a shear wave image corresponding to the region selected on the B-mode image of FIG. 6, and such a step is added to the flowchart of FIG. Also good. Thereby, the shear wave image of the corresponding region in the B-mode image can be easily confirmed, and the usability is improved.

Abstract

Ultrasonic diagnostic equipment and a shear wave propagation image generating method are provided wherein laminographic images can be acquired with a single ultrasonic probe and elasticity information using shear waves can be acquired. In a process of acquiring laminographic images based on reflective-echo signals received from an ultrasonic probe (4) that transmits/receives ultrasonic waves to/from a subject (5), a vibrator (3) is used to cause shear waves to occur in the subject (5) and shear wave images are generated and displayed.

Description

超音波診断装置、せん断波の伝搬画像生成方法Ultrasonic diagnostic apparatus, shear wave propagation image generation method
　本発明は、超音波を利用して生体組織等の弾性情報を求め、表示する超音波診断装置、せん断波の伝搬画像生成方法に関する。 The present invention relates to an ultrasonic diagnostic apparatus that obtains and displays elasticity information of a living tissue or the like using ultrasonic waves, and a shear wave propagation image generation method.
　超音波診断装置は、超音波プローブにより生体組織等に超音波を送信し、生体組織等の構造に応じた超音波の反射エコー信号を受信し、超音波断層画像を生成して表示する。また、用手法又は機械的な方法により超音波プローブで生体組織等を圧迫して、計測時間が異なる2つの超音波信号のフレームデータに基づいた生体組織の変位を求め、その変位データから生体組織の硬さ又は軟らかさの弾性情報を示す弾性画像を生成することができる。 The ultrasonic diagnostic apparatus transmits an ultrasonic wave to a biological tissue or the like by an ultrasonic probe, receives an ultrasonic reflected echo signal corresponding to the structure of the biological tissue or the like, and generates and displays an ultrasonic tomographic image. In addition, the biological tissue or the like is compressed with an ultrasonic probe using a technique or a mechanical method, and the displacement of the biological tissue is obtained based on the frame data of two ultrasonic signals having different measurement times, and the biological tissue is obtained from the displacement data. It is possible to generate an elasticity image showing elasticity information on the hardness or softness of the image.
　さらに、超音波を利用して弾性情報を得るための方法として、生体等に加えられた低周波(～1kHz程度)の振動により生じるせん断波と呼ばれる波を利用する方法がある。せん断波の伝搬速度は伝搬媒体の硬さを示し、せん断弾性係数の平方根に比例するので、超音波によりせん断波の伝搬速度を計測することで、生体組織の弾性情報を求めることができる。このような技術の例として、特許文献1，2が挙げられる。 Furthermore, as a method for obtaining elasticity information using ultrasonic waves, there is a method using a wave called a shear wave generated by a low frequency (about 1 kHz) vibration applied to a living body or the like. Since the propagation speed of the shear wave indicates the hardness of the propagation medium and is proportional to the square root of the shear elastic modulus, the elasticity information of the living tissue can be obtained by measuring the propagation speed of the shear wave using ultrasonic waves. Examples of such techniques include Patent Documents 1 and 2.
特表2005-534455号公報Special Table 2005-534455 特開2007-44231号公報JP 2007-44231 A
　特許文献1では、せん断波の伝搬速度を計測するための専用プローブを用いているが、このプローブのみでは被検体の断層画像を取得できないので、断層画像を確認しながら、弾性情報を得たい箇所のせん断波の伝搬速度を計測することができない。 In Patent Document 1, a dedicated probe for measuring the propagation speed of shear waves is used. However, a tomographic image of the subject cannot be acquired with this probe alone. The shear wave propagation velocity cannot be measured.
　また、特許文献1，2には、断層画像取得用のプローブに、せん断波の伝搬速度を計測する専用プローブを取り付けることも記載されているが、2つのプローブが必要となり、また、断層画像取得用とせん断波の伝搬速度計測用に2系統の超音波送受信部が必要となるため、その操作、構成が煩雑となる。 Patent Documents 1 and 2 also describe that a dedicated probe for measuring the propagation speed of shear waves is attached to a probe for tomographic image acquisition, but two probes are required, and tomographic image acquisition is also required. Since two ultrasonic transmission / reception units are required for measuring the propagation speed of shear waves and shear waves, the operation and configuration become complicated.
　本発明が解決しようとする課題は、1つの超音波プローブで断層画像を取得するとともに、せん断波による弾性情報を取得できる超音波診断装置、せん断波の伝搬画像生成方法を提供することにある。 The problem to be solved by the present invention is to provide an ultrasonic diagnostic apparatus and a shear wave propagation image generation method capable of acquiring tomographic images with one ultrasonic probe and acquiring elastic information by shear waves.
　上記課題を解決するため、本発明の超音波診断装置は、被検体との間で超音波を送受する超音波プローブと、前記被検体にせん断波を発生させる振動体と、前記超音波プローブとの間で前記超音波の送信及び受信処理を行う送受信部と、該送受信部により受信処理された反射エコー信号に基づいて断層画像を構成する断層画像構成部とを備えた超音波診断装置であって、前記送受信部によって、前記超音波を前記被検体に対して時間間隔をおいて送受信し、該送受信に基づいてせん断波の伝搬情報を求めるせん断波伝搬位置検出部と、該求めたせん断波の伝搬情報を表すせん断波画像を構成するせん断波画像構成部と、前記せん断波画像と前記断層画像とを表示する画像表示部とを備える。 In order to solve the above problems, an ultrasonic diagnostic apparatus of the present invention includes an ultrasonic probe that transmits and receives ultrasonic waves to and from a subject, a vibrator that generates shear waves in the subject, and the ultrasonic probe. An ultrasonic diagnostic apparatus comprising: a transmission / reception unit that performs transmission and reception processing of the ultrasonic wave between; and a tomographic image configuration unit that forms a tomographic image based on the reflected echo signal received and processed by the transmission / reception unit. The transmission / reception unit transmits / receives the ultrasonic wave to / from the subject at a time interval and obtains shear wave propagation information based on the transmission / reception, and the obtained shear wave A shear wave image constituting unit that constitutes a shear wave image representing the propagation information of the image, and an image display unit that displays the shear wave image and the tomographic image.
　本発明によれば、同一の超音波プローブを用いて断層画像取得用の超音波を送受信しながら走査する一方、断層画像取得用の超音波の送受信を設定された時間間隔ごとに休止し、その休止時にせん断波の伝搬位置検出用の超音波を被検体に送受信することで、断層画像を取得しながらせん断波の伝搬情報を取得することができる。これにより、断層画像取得用のプローブとせん断波の伝搬速度を計測用プローブの2つのプローブが無くても、断層画像とともにせん断波の伝搬情報を取得できる。せん断波の伝搬情報には、せん断波の伝搬位置と伝搬時間が含まれており、これらの関係からせん断波の伝搬速度を求めることができる。せん断波の伝搬位置は、伝搬位置検出測用の超音波が、せん断波に反射して戻るまでの時間と超音波の速度から求められる。これにより、生体組織の硬さ又は軟らかさの弾性情報を取得できる。また、断層画像取得用とせん断波の伝搬位置検出用の超音波送受信部をそれぞれ設けることも、1つを共用することもできる。なお、せん断波の伝搬位置と伝搬時間の関係を正確に求めるには、伝搬位置検出用の超音波は1フレームのうちできるだけ多く送受信することが望ましい。 According to the present invention, scanning is performed while transmitting and receiving ultrasonic waves for acquiring tomographic images using the same ultrasonic probe, while transmission and reception of ultrasonic waves for acquiring tomographic images is paused at set time intervals, By transmitting / receiving ultrasonic waves for detecting the propagation position of shear waves to / from the subject at rest, shear wave propagation information can be acquired while acquiring a tomographic image. Accordingly, the propagation information of the shear wave can be acquired together with the tomographic image without the two probes of the probe for acquiring the tomographic image and the probe for measuring the propagation speed of the shear wave. The shear wave propagation information includes the shear wave propagation position and propagation time, and the shear wave propagation speed can be obtained from these relationships. The propagation position of the shear wave is obtained from the time until the ultrasonic wave for detecting the propagation position is reflected back to the shear wave and the velocity of the ultrasonic wave. Thereby, the elasticity information of the hardness or softness of the living tissue can be acquired. In addition, ultrasonic transmission / reception units for tomographic image acquisition and shear wave propagation position detection can be provided, respectively, or one can be shared. In order to accurately obtain the relationship between the propagation position of the shear wave and the propagation time, it is desirable to transmit and receive as many ultrasonic waves for detecting the propagation position as possible in one frame.
　この場合において、被検体に対して伝搬位置検出用の超音波を送受信する方向を設定する方向設定部を設け、方向設定部に、画像表示部に表示された断層画像上に方向(設定方向)を示す計測ラインを生成する計測ライン生成部を備えるように構成することもできる。これにより、計測ライン上のせん断波の伝搬情報及び弾性情報を取得することができる。また、せん断波画像を得たいラインを断層画像を参照して決めることができる。ラインを動かす場合には、超音波プローブを動かすか、伝搬位置検出用の超音波を送信する口径を変更すればよい。 In this case, a direction setting unit that sets a direction for transmitting and receiving ultrasonic waves for detecting a propagation position with respect to the subject is provided, and the direction setting unit has a direction (setting direction) on the tomographic image displayed on the image display unit. It can also comprise so that the measurement line production | generation part which produces | generates the measurement line which shows may be provided. Thereby, propagation information and elasticity information of the shear wave on the measurement line can be acquired. Further, a line from which a shear wave image is to be obtained can be determined with reference to the tomographic image. When moving the line, the ultrasonic probe may be moved or the aperture for transmitting the ultrasonic wave for detecting the propagation position may be changed.
　また、伝搬画像構成部を、被検体に対するせん断波の深度とせん断波の発生からの経過時間とに基づいてせん断波画像を構成するようにすることもできる。 Also, the propagation image construction unit can construct a shear wave image based on the depth of the shear wave with respect to the subject and the elapsed time from the generation of the shear wave.
　また、伝搬画像構成部を、画像表示部に表示された断層画像上で選択した領域に対応するせん断波画像を画像表示部に表示するように構成することもできる。これにより、断層画像に対応する領域のせん断波画像を容易に確認することができ、使い勝手がよくなる。 Also, the propagation image forming unit can be configured to display a shear wave image corresponding to a region selected on the tomographic image displayed on the image display unit on the image display unit. Thereby, the shear wave image of the area | region corresponding to a tomographic image can be confirmed easily, and usability improves.
　さらに、超音波診断装置に、せん断波画像に基づいて弾性率分布を演算する弾性情報演算部を備えることができる。また、画像表示部を、弾性率分布を断層画像に対応付けて合成して表示するように構成することもできる。これにより、断層画像上で弾性率分布を確認することが容易になり、使い勝手がよくなる。 Furthermore, the ultrasonic diagnostic apparatus can be provided with an elastic information calculation unit for calculating an elastic modulus distribution based on the shear wave image. In addition, the image display unit can be configured to display the combined elastic modulus distribution in association with the tomographic image. This makes it easy to confirm the elastic modulus distribution on the tomographic image, and improves usability.
　また、送受信部により受信処理された反射エコー信号に基づいてMモード画像を構成するMモード画像構成部を備え、画像表示部に断層画像とせん断波画像とMモード画像とを並置して表示するように構成することもできる。さらに、送受信部を、Mモード画像上の変化を検知して伝搬位置検出用の超音波の送信を開始するように構成することもできる。 In addition, an M mode image configuration unit that configures an M mode image based on the reflected echo signal received and processed by the transmission / reception unit is provided, and the tomographic image, the shear wave image, and the M mode image are displayed side by side on the image display unit. It can also be configured as follows. Furthermore, the transmission / reception unit may be configured to detect the change on the M-mode image and start transmitting the ultrasonic wave for detecting the propagation position.
　また、被検体に超音波プローブを介して圧力を加える過程における反射エコー信号を受信処理してRFフレームデータを生成する弾性画像構成部と、断層画像に代えて弾性画像とせん断波画像とを並置して表示する表示方式、または、弾性画像とせん断波画像と断層画像とを並置して表示する表示方式のいずれかの表示方式を選択する表示選択部とを備え、画像表示部を、選択された表示方式の画像を表示するように構成することもできる。 In addition, an elastic image constructing unit that generates RF frame data by receiving and processing a reflected echo signal in the process of applying pressure to the subject via an ultrasonic probe, and an elastic image and a shear wave image are juxtaposed instead of the tomographic image A display selection unit that selects either a display method for displaying the image, or a display method for displaying the elastic image, the shear wave image, and the tomographic image in parallel, and the image display unit is selected. It is also possible to configure to display an image of a different display method.
　超音波診断装置によるせん断波の伝搬画像生成方法としては、超音波プローブにより被検体との間で超音波を送受し、振動体により超音波プローブに設けられ被検体にせん断波を発生させ、送受信部により超音波プローブとの間で超音波の送信及び受信処理を行い、断層画像構成部により送受信部により受信処理された反射エコー信号に基づいて断層画像を構成し、送受信部により、伝搬位置検出用の超音波を被検体に対して時間間隔をおいて送受信する第1のステップと、せん断波伝搬検出部により、第1のステップにおける送受信に基づいてせん断波の伝搬情報を求める第2のステップと、伝搬画像構成部により求めたせん断波の伝搬情報を表すせん断波画像を構成する第3のステップと、画像表示部にせん断波画像と断層画像とを対応付けて表示する第4のステップとを含むように構成する。 As a method of generating a propagation image of shear waves using an ultrasonic diagnostic apparatus, ultrasonic waves are transmitted to and received from an object using an ultrasonic probe, shear waves are generated in the object provided on the ultrasonic probe by a vibrating body, and transmitted and received. The ultrasonic transmission and reception processing is performed with the ultrasonic probe by the unit, the tomographic image is configured based on the reflected echo signal received and processed by the transmission and reception unit by the tomographic image configuration unit, and the propagation position is detected by the transmission and reception unit. First step of transmitting / receiving ultrasonic waves to / from the subject at time intervals, and a second step of obtaining shear wave propagation information based on transmission / reception in the first step by the shear wave propagation detection unit And a third step for constructing a shear wave image representing shear wave propagation information obtained by the propagation image construction unit, and associating the shear wave image and the tomographic image with the image display unit And a fourth step of displaying.
　また、第1のステップを、方向設定部により被検体に対してせん断波の伝搬位置検出用の超音波を送受信する方向を設定するステップと、方向設定部により画像表示部に表示された断層画像上に、計測ライン生成部により方向を示す計測ラインを生成するステップとを含むように構成することもでき、第3のステップを、伝搬画像構成部により画像表示部に表示された断層画像上で選択した領域に基づきせん断波画像を構成するステップを含むように構成することもできる。 Further, the first step includes a step of setting a direction for transmitting and receiving ultrasonic waves for detecting a propagation position of shear waves to the subject by the direction setting unit, and a tomographic image displayed on the image display unit by the direction setting unit. And a step of generating a measurement line indicating a direction by the measurement line generation unit, and the third step is performed on the tomographic image displayed on the image display unit by the propagation image configuration unit. It can also be configured to include a step of constructing a shear wave image based on the selected region.
　また、第4のステップを、弾性情報演算部によりせん断波画像に基づいて弾性率分布を演算し、画像表示部に弾性率分布を断層画像に対応付けて合成して表示するステップと、Mモード画像構成部により送受信部により受信処理された反射エコー信号に基づいてMモード画像を構成するステップと、画像表示部にMモード画像と断層画像とせん断波画像とを並置して表示するステップとを含むように構成することもできる。 Further, the fourth step is a step of calculating an elastic modulus distribution based on the shear wave image by the elastic information calculating unit, and combining and displaying the elastic modulus distribution in association with the tomographic image on the image display unit, and an M mode. A step of constructing an M mode image based on the reflected echo signal received and processed by the transmission / reception unit by the image construction unit, and a step of juxtaposing and displaying the M mode image, the tomographic image, and the shear wave image on the image display unit It can also be configured to include.
　さらに、第4のステップを、弾性画像構成部により被検体に超音波プローブを介して圧力を加える過程における反射エコー信号を受信処理してRFフレームデータを生成し、該RFフレームデータから弾性画像を構成するステップと、表示選択部により断層画像に代えて弾性画像とせん断波画像とを並置して表示する表示方式、または、弾性画像とせん断波画像と断層画像とを並置して表示する表示方式のいずれかの表示方式を選択するステップと、画像表示部に選択された表示方式の画像を表示するステップを含むように構成することもできる。 Further, in the fourth step, the reflected image signal in the process of applying pressure to the subject via the ultrasonic probe by the elastic image forming unit is received to generate RF frame data, and the elastic image is generated from the RF frame data. A display method in which an elastic image and a shear wave image are displayed side by side instead of a tomographic image by a display step, or a display method in which an elastic image, a shear wave image, and a tomographic image are displayed in parallel It is also possible to include a step of selecting any one of the display methods and a step of displaying an image of the selected display method on the image display unit.
　本発明によれば、1つの超音波プローブで断層画像を取得するとともに、せん断波による弾性情報を取得できる超音波診断装置を提供することができる。 According to the present invention, it is possible to provide an ultrasonic diagnostic apparatus capable of acquiring a tomographic image with one ultrasonic probe and acquiring elastic information by shear waves.
本発明の超音波診断装置の構成図Configuration diagram of the ultrasonic diagnostic apparatus of the present invention (a)は超音波プローブの構成であり、(b)は超音波プローブから送信される超音波の様子(a) shows the configuration of the ultrasonic probe, and (b) shows the state of the ultrasonic wave transmitted from the ultrasonic probe. 超音波送信のタイミングチャートUltrasonic transmission timing chart せん断波の深度と時間の関係を示す図Diagram showing the relationship between shear wave depth and time 画像表示部に表示されるせん断波画像の一例Example of shear wave image displayed on image display Bモード画像、Mモード画像、せん断波画像が表示された画面Screen displaying B-mode image, M-mode image, and shear wave image Bモード画像上に弾性情報が表示された画面Screen with elasticity information displayed on the B-mode image せん断波による弾性情報を取得するまでのフローチャートFlow chart until acquiring elastic information by shear wave
　以下、本発明の超音波診断装置の実施の形態について、図面を参照して説明する。図1に示すように、本実施形態の超音波診断装置は、被検体5との間で超音波を送受する超音波プローブ4と、超音波プローブ4に着脱可能な機構を有し、超音波プローブ4を介して被検体5に低周波振動を印加してせん断波を発生させる振動体3と、超音波プローブ4を介して被検体5に時間間隔をおいて超音波を繰り返し送信する送信部2と、被検体5から発生する時系列の反射エコー信号を受信する受信部6と、送信部2と受信部6を制御する超音波送受信制御部1と、受信部6で受信された反射エコー信号を整相加算する整相加算部7とを備えている。 Hereinafter, embodiments of the ultrasonic diagnostic apparatus of the present invention will be described with reference to the drawings. As shown in FIG. 1, the ultrasonic diagnostic apparatus of the present embodiment includes an ultrasonic probe 4 that transmits and receives ultrasonic waves to and from a subject 5, and a mechanism that can be attached to and detached from the ultrasonic probe 4. A vibrating body 3 that generates a shear wave by applying a low-frequency vibration to the subject 5 via the probe 4 and a transmitter that repeatedly transmits ultrasonic waves to the subject 5 via the ultrasonic probe 4 at time intervals. 2, a receiving unit 6 that receives a time-series reflected echo signal generated from the subject 5, an ultrasonic transmission / reception control unit 1 that controls the transmitting unit 2 and the receiving unit 6, and a reflected echo received by the receiving unit 6 And a phasing adder 7 for phasing and adding signals.
　また、整相加算部7からのRF(Radio Frequency)フレーム信号に基づいて被検体5の濃淡断層画像、例えば白黒断層画像を構成する断層画像構成部8と、断層画像構成部8の出力信号を画像表示部18の表示に合うように変換する白黒スキャンコンバータ9とを備えている。 Further, based on the RF (Radio Frequency) frame signal from the phasing adder 7, the tomographic image constructing unit 8 constituting the tomographic image of the subject 5, for example, a black and white tomographic image, and the output signal of the tomographic image constructing unit 8 And a black and white scan converter 9 for converting the image display unit 18 so as to match the display.
　また、整相加算部7から出力されるRFフレーム信号を格納するフレームデータメモリ10aと、被検体5の生体組織に生じた変位を計測する変位計測部10と、変位計測部10で計測された変位情報から連続的な圧迫過程における弾性情報を算出するための歪み又は弾性率を求める弾性情報演算部11と、弾性情報演算部11で演算した歪み又は弾性率からカラー弾性画像を構成する弾性画像構成部12と、弾性画像構成部12の出力信号を画像表示部18の表示に合うように変換するカラースキャンコンバータ13とを備えている。 Further, the frame data memory 10a that stores the RF frame signal output from the phasing addition unit 7, the displacement measurement unit 10 that measures the displacement generated in the living tissue of the subject 5, and the displacement measurement unit 10 Elasticity information calculation unit 11 for obtaining strain or elastic modulus for calculating elasticity information in a continuous compression process from displacement information, and an elastic image constituting a color elasticity image from the strain or elastic modulus calculated by the elasticity information calculation unit 11 A configuration unit 12 and a color scan converter 13 that converts the output signal of the elastic image configuration unit 12 to match the display of the image display unit 18 are provided.
　ここで、整相加算部7から出力される後に詳述するRFライン信号を格納するラインデータメモリ14aと、被検体5に対してせん断波の伝搬位置検出用の超音波21を送受信する方向を設定する方向設定部14bと、せん断波の伝搬情報を求めるせん断波伝搬位置検出部14と、せん断波伝搬位置検出部14で求めた伝搬情報から弾性情報を算出するためのヤング率を求めるせん断波弾性情報演算部15と、せん断波伝搬位置検出部14で求めた伝搬情報から時間軸を基準とする像を生成するせん断波画像構成部16とを備えることである。なお、せん断波画像構成部16の出力信号は、カラースキャンコンバータ13により画像表示部18の表示に合うように変換されるようになっている。 Here, the line data memory 14a for storing an RF line signal, which will be described in detail later, outputted from the phasing adder 7, and the direction in which the ultrasonic wave 21 for detecting the propagation position of the shear wave is transmitted to and received from the subject 5 are transmitted. Direction setting unit 14b for setting, shear wave propagation position detection unit 14 for obtaining propagation information of shear wave, and shear wave for obtaining Young's modulus for calculating elastic information from propagation information obtained by shear wave propagation position detection unit 14 An elastic information calculation unit 15 and a shear wave image construction unit 16 that generates an image based on the time axis from the propagation information obtained by the shear wave propagation position detection unit 14 are provided. Note that the output signal of the shear wave image constructing unit 16 is converted by the color scan converter 13 so as to match the display of the image display unit 18.
　そして、白黒断層画像とカラー弾性画像を重ね合わせたり、並列に表示させたり、切り替えたりする切替え加算部17と、合成された合成画像を表示する画像表示部18と、画像を選択、操作するための操作卓19とを備えている。 In order to select and manipulate an image, a switching addition unit 17 that superimposes a monochrome tomographic image and a color elastic image, displays them in parallel, or switches them, an image display unit 18 that displays a synthesized composite image, and The console 19 is provided.
　ここで、本実施形態の超音波診断装置における一般的な構成部分の動作について説明する。超音波プローブ4は、複数の振動子を配設して形成されており、被検体5に振動子を介して超音波を送受信する機能を有している。送信部2は、超音波プローブ4を駆動して超音波を発生させるための送波パルスを生成するとともに、送信される超音波の収束点をある深さに設定する機能を有している。 Here, the operation of general components in the ultrasonic diagnostic apparatus of this embodiment will be described. The ultrasonic probe 4 is formed by arranging a plurality of transducers, and has a function of transmitting and receiving ultrasonic waves to and from the subject 5 via the transducers. The transmission unit 2 generates a transmission pulse for generating an ultrasonic wave by driving the ultrasonic probe 4, and has a function of setting a convergence point of the transmitted ultrasonic wave to a certain depth.
　また、受信部6は、超音波プローブ4で受信した反射エコー信号について所定のゲインで増幅してRF信号すなわち受波信号を生成するものである。整相加算部7は、受信部6で増幅されたRF信号を入力して位相制御し、一点又は複数の収束点に対し超音波ビームを形成してRFフレーム信号を生成するものである。断層画像構成部8は、整相加算部7からのRFフレーム信号を入力してゲイン補正、ログ圧縮、検波、輪郭強調、フィルタ処理等の信号処理を行い、Bモード画像、Mモード画像等の断層画像データを得るものである。 The receiving unit 6 amplifies the reflected echo signal received by the ultrasonic probe 4 with a predetermined gain to generate an RF signal, that is, a received signal. The phasing / adding unit 7 inputs the RF signal amplified by the receiving unit 6 and performs phase control, and forms an ultrasonic beam at one point or a plurality of convergence points to generate an RF frame signal. The tomographic image construction unit 8 receives the RF frame signal from the phasing addition unit 7 and performs signal processing such as gain correction, log compression, detection, contour enhancement, filter processing, and so forth, such as a B-mode image and an M-mode image. The tomographic image data is obtained.
　白黒スキャンコンバータ9は、断層画像構成部8からの断層画像データをデジタル信号に変換する図示しないアナログ／デジタル変換器と変換された複数の断層画像データを時系列に記憶するフレームメモリと制御コントローラとを含んで構成されている。白黒スキャンコンバータ9は、フレームメモリに格納された被検体5内の断層フレームデータを1画像として取得し、取得された断像フレームデータをテレビ同期で読み出すものである。 The black-and-white scan converter 9 includes an analog / digital converter (not shown) that converts tomographic image data from the tomographic image construction unit 8 into a digital signal, a frame memory that stores a plurality of converted tomographic image data in time series, a control controller, It is comprised including. The black-and-white scan converter 9 acquires tomographic frame data in the subject 5 stored in the frame memory as one image, and reads the acquired framed frame data in synchronization with the television.
　次に、超音波プローブ4を介して被検体5を圧迫して弾性情報を得る場合の動作について説明する。整相加算部7から出力されたRFフレーム信号は、適宜選択されてフレームデータメモリ10aに記録される。変位計測部10は、フレームデータメモリ10aの1組のデータから、1次元あるいは2次元相関処理を行って、断層画像の各点に対応する生体組織における変位や移動ベクトル、すなわち変位の方向と大きさに関する1次元又は2次元変位分布を求める。 Next, the operation in the case of obtaining elasticity information by pressing the subject 5 via the ultrasonic probe 4 will be described. The RF frame signal output from the phasing adder 7 is appropriately selected and recorded in the frame data memory 10a. The displacement measurement unit 10 performs one-dimensional or two-dimensional correlation processing from one set of data in the frame data memory 10a, and performs displacement and movement vectors in the biological tissue corresponding to each point of the tomographic image, that is, the direction and magnitude of the displacement. Find the one-dimensional or two-dimensional displacement distribution on the height.
　移動ベクトルの検出方法の一つに、例えばブロックマッチング法が挙げられる。ブロックマッチング法とは、画像を例えばＮ×Ｎ画素からなるブロックに分け、関心領域内のブロックに着目し、着目しているブロックに最も近似しているブロックを前のフレームから探し、これを参照して予測符号化、すなわち差分により標本値を決定する処理を行うものである。 One example of the movement vector detection method is a block matching method. The block matching method divides an image into blocks of N × N pixels, for example, pays attention to the block in the region of interest, searches the previous frame for the block that is closest to the block of interest, and refers to this Thus, predictive encoding, that is, processing for determining the sample value by the difference is performed.
　弾性情報演算部11は、変位計測部10から出力されるデータに対し、歪みあるいは弾性率を演算するものである。例えば、弾性率を演算する場合、超音波プローブ4に接続された図示していない圧力センサーによって計測された圧力値を用いることができるが、変位計測部10からの出力データから歪みデータを算出する必要がある。この歪みデータは、生体組織の移動量、例えば変位を空間微分することによって算出される。また、弾性率のデータは、圧力の変化を歪みの変化で除することによって計算される。 The elasticity information calculation unit 11 calculates strain or elastic modulus for the data output from the displacement measurement unit 10. For example, when calculating the elastic modulus, a pressure value measured by a pressure sensor (not shown) connected to the ultrasonic probe 4 can be used, but strain data is calculated from output data from the displacement measuring unit 10. There is a need. This strain data is calculated by spatially differentiating the movement amount of the living tissue, for example, the displacement. The elastic modulus data is calculated by dividing the change in pressure by the change in strain.
　変位計測部10により計測された変位をL(x)、圧力センサーにより計測された圧力をP(x)とすると、歪みΔS(x)は、L(x)を空間微分することによって算出することができるから、ΔS(x)＝ΔL(x)／Δxという式を用いて求められる。 Assuming that the displacement measured by the displacement measuring unit 10 is L (x) and the pressure measured by the pressure sensor is P (x), the strain ΔS (x) is calculated by spatially differentiating L (x). Therefore, ΔS (x) = ΔL (x) / Δx can be obtained.
　また、弾性率データであるヤング率Ym(x)は、Ym(x)＝(ΔP(x))／ΔS(x)という式によって算出される。ヤング率から断層画像の各点に相当する生体組織の弾性率が求められるので、2次元の弾性画像データを連続的に得ることができる。なお、ヤング率とは、物体に加えられた単純引張り応力と引張りに平行に生じるひずみに対する比である。 The Young's modulus Ym (x), which is elastic modulus data, is calculated by the equation Ym (x) = (ΔP (x)) / ΔS (x). Since the elastic modulus of the living tissue corresponding to each point of the tomographic image is obtained from the Young's modulus, two-dimensional elastic image data can be obtained continuously. The Young's modulus is a ratio of a simple tensile stress applied to an object and a strain generated in parallel to the tension.
　弾性画像構成部12は、図示しないフレームメモリと画像処理部とで構成されており、弾性情報演算部11から時系列に出力される弾性フレームデータをフレームメモリに確保し、確保されたフレームデータに対し所望の画像処理を行うものである。カラースキャンコンバータ13は、弾性画像構成部12と後述するせん断波画像構成部16からの弾性画像データに色相情報を付与する機能を有したものである。 The elastic image construction unit 12 includes a frame memory (not shown) and an image processing unit, and secures the elastic frame data output in time series from the elastic information calculation unit 11 in the frame memory. On the other hand, desired image processing is performed. The color scan converter 13 has a function of adding hue information to elastic image data from the elastic image construction unit 12 and a shear wave image construction unit 16 described later.
　つまり、弾性フレームデータに基づいて光の3原色、すなわち赤(R)、緑(G)、青(B)に変換するものである。配色の一例として、例えば、歪みが大きい弾性データを赤色コードに変換すると同時に、歪みが小さい弾性データを青色コードに変換するものである。 That is, based on the elastic frame data, the light is converted into three primary colors, that is, red (R), green (G), and blue (B). As an example of the color scheme, for example, elastic data having a large strain is converted into a red code, and simultaneously elastic data having a small strain is converted into a blue code.
　本実施形態の特徴となる構成は、特に被検体5との間で超音波を送受する超音波プローブ4と、被検体5にせん断波を発生させる振動体3と、超音波プローブ4との間で超音波の送信及び受信処理を行う送受信部2，6と、該送受信部2，6により受信処理された反射エコー信号に基づいて断層画像を構成する断層画像構成部8とを備えた超音波診断装置であって、送受信部2，6によって、超音波を被検体5に対して時間間隔をおいて送受信し、該送受信に基づいてせん断波の伝搬情報を求めるせん断波伝搬位置検出部14と、該求めたせん断波の伝搬情報を表すせん断波画像を構成するせん断波画像構成部16と、せん断波画像と断層画像とを表示する画像表示部18とを備えることである。 The configuration that is a feature of the present embodiment is, in particular, between the ultrasonic probe 4 that transmits and receives ultrasonic waves to and from the subject 5, the vibrator 3 that generates shear waves in the subject 5, and the ultrasonic probe 4. Transmission / reception units 2 and 6 that perform transmission and reception processing of ultrasonic waves, and a tomographic image configuration unit 8 that forms a tomographic image based on the reflected echo signals received and processed by the transmission / reception units 2 and 6 A diagnostic apparatus, wherein transmission / reception units 2 and 6 transmit and receive ultrasonic waves to and from a subject 5 at time intervals, and obtain shear wave propagation information based on the transmission and reception, and a shear wave propagation position detection unit 14 A shear wave image constructing unit 16 that constitutes a shear wave image representing the obtained shear wave propagation information, and an image display unit 18 that displays the shear wave image and the tomographic image are provided.
　ここで、本実施形態の特徴となる構成の動作を説明する。前述したように、被検体5に対してせん断波を発生させるためには、～1kHz程度の低周波振動を印加する必要がある。このため、超音波プローブ4には、図2(a)に示すように、着脱が可能な振動体3が装着される。振動体3から発せられる振動は、連続的又は単発的な振動のどちらでもよい。 Here, the operation of the configuration that characterizes the present embodiment will be described. As described above, in order to generate a shear wave on the subject 5, it is necessary to apply a low frequency vibration of about 1 kHz. Therefore, as shown in FIG. 2 (a), the detachable vibrator 3 is attached to the ultrasonic probe 4. The vibration emitted from the vibrating body 3 may be either continuous or single vibration.
　このときに送信部2から超音波プローブ4を介して被検体5に照射される超音波は、図2(b)に示すように、断層画像取得用の超音波20と、せん断波の伝搬位置検出用の超音波21がある。断層画像取得用の超音波20は、超音波プローブ4内に複数個配列された振動子を順次切り替えて送信するものである。せん断波の伝搬位置検出用の超音波21の送信方向は予め決めておく。本実施形態では、被検体5の深度方向である。 At this time, as shown in FIG. 2 (b), the ultrasonic wave irradiated to the subject 5 from the transmitting unit 2 via the ultrasonic probe 4 includes the ultrasonic wave 20 for tomographic image acquisition and the propagation position of the shear wave. There is an ultrasonic wave 21 for detection. The ultrasonic wave 20 for tomographic image acquisition is to transmit a plurality of transducers arranged in the ultrasonic probe 4 by sequentially switching them. The transmission direction of the ultrasonic wave 21 for detecting the propagation position of the shear wave is determined in advance. In the present embodiment, it is the depth direction of the subject 5.
　一方、伝搬位置検出用の超音波21は、超音波プローブ4内に複数個配列された振動子のうち、チャンネルとして予め設定された箇所からのみ送信される。図2(b)では、超音波プローブ4の真ん中の振動子がチャンネルとして設定されている。図3に、断層画像取得用の超音波20と、伝搬位置検出用の超音波21の送信タイミングチャートを示す。図3に示すように、伝搬位置検出用の超音波21は、断層画像取得用の超音波20が複数送信されるごとに1回送信され、その送信間隔はαで、これは、伝搬位置検出用の超音波21のPRF(パルス繰り返し周波数)であり、1フレーム内で複数回送信される。 On the other hand, the ultrasonic wave 21 for detecting the propagation position is transmitted only from a portion set in advance as a channel among a plurality of transducers arranged in the ultrasonic probe 4. In FIG. 2 (b), the transducer in the middle of the ultrasonic probe 4 is set as a channel. FIG. 3 shows a transmission timing chart of the ultrasonic wave 20 for tomographic image acquisition and the ultrasonic wave 21 for propagation position detection. As shown in FIG. 3, the ultrasonic wave 21 for detecting the propagation position is transmitted once every time a plurality of ultrasonic waves 20 for acquiring the tomographic image are transmitted, and the transmission interval is α. PRF (pulse repetition frequency) of the ultrasonic wave 21 for use, and is transmitted a plurality of times within one frame.
　このように送信された伝搬位置検出用の超音波21の受信信号は、順次ラインデータメモリ14aに記録される。この受信信号は、伝搬位置検出用の超音波21が、せん断波に当たって反射する際にせん断波の影響を受けた信号である。せん断波伝搬位置検出部14は、複数の受信信号からせん断波の伝搬情報を求める。せん断波の伝搬情報には、せん断波の伝搬位置と伝搬時間が含まれる。せん断波の伝搬位置は、伝搬位置検出用の超音波21が、せん断波に反射して戻るまでの時間と超音波の速度から求められる。 The reception signal of the ultrasonic wave 21 for detecting the propagation position transmitted in this way is sequentially recorded in the line data memory 14a. This received signal is a signal affected by the shear wave when the ultrasonic wave 21 for detecting the propagation position is reflected by the shear wave. The shear wave propagation position detector 14 obtains shear wave propagation information from a plurality of received signals. The shear wave propagation information includes the shear wave propagation position and propagation time. The propagation position of the shear wave is obtained from the time until the ultrasonic wave 21 for detecting the propagation position is reflected back to the shear wave and the velocity of the ultrasonic wave.
　図4に、せん断波の位置である深度(縦軸)と時間(横軸)との関係を表すグラフを示す。図4中の矩形は、せん断波の伝搬に伴って生じる変位であり、矩形の紙面縦方向の幅はせん断波の波数に相当し、紙面横方向の幅は振幅に相当する。せん断波は時間の経過とともに被検体5の内部に伝搬するが、伝搬位置検出用の超音波21により求められるその深度と時間(αの逆数)とで、伝搬速度を演算することが可能となる。 Fig. 4 shows a graph showing the relationship between the depth (vertical axis) and the time (horizontal axis), which are the shear wave positions. The rectangles in FIG. 4 are displacements generated along with the propagation of the shear wave. The width of the rectangle in the vertical direction of the paper corresponds to the wave number of the shear wave, and the width in the horizontal direction of the paper corresponds to the amplitude. The shear wave propagates to the inside of the subject 5 with the passage of time, but the propagation speed can be calculated by the depth and time (reciprocal of α) obtained by the ultrasonic wave 21 for detecting the propagation position. .
　せん断波弾性情報演算部15は、伝搬速度からせん断波による弾性情報を演算する。ヤング率をE、媒体の密度をρ、伝搬速度をVｓとすると、E＝3ρVｓ2でという式で表されるので、これを用いてヤング率を演算する。 The shear wave elasticity information calculation unit 15 calculates the elasticity information by the shear wave from the propagation velocity. If the Young's modulus is E, the density of the medium is ρ, and the propagation velocity is Vs, E = 3ρVs2, which is used to calculate the Young's modulus.
　せん断波画像構成部16は、せん断波伝搬位置検出部14で求めた深度方向のせん断波の伝搬情報からせん断波画像と、せん断波弾性情報演算部15で求めたせん断波による弾性情報のグラフを構成し、カラースキャンコンバータ13は、それを画像化する。図5(a)、(b)にせん断波画像の一例を示す。図5(a)、(b)では、縦軸に深度(上が0)、横軸に時間をとっており、傾きが伝搬速度を表している。伝搬速度は媒体が硬いほど早くなるため、図5(a)は図5(b)よりも媒体が硬いことを示している。なお、せん断波による弾性情報のグラフは、縦軸にヤング率、横軸に深度をとるもので、本実施形態では、図7のBモード画像上に示されている。 The shear wave image construction unit 16 generates a shear wave image from the shear wave propagation information in the depth direction obtained by the shear wave propagation position detection unit 14 and a graph of the elasticity information by the shear wave obtained by the shear wave elasticity information calculation unit 15. Configure and color scan converter 13 images it. FIGS. 5A and 5B show examples of shear wave images. In FIGS. 5 (a) and 5 (b), the vertical axis represents depth (upper side is 0) and the horizontal axis represents time, and the slope represents the propagation speed. Since the propagation speed increases as the medium becomes harder, FIG. 5 (a) shows that the medium is harder than in FIG. 5 (b). Note that the elastic information graph based on shear waves has a Young's modulus on the vertical axis and a depth on the horizontal axis, and is shown on the B-mode image in FIG. 7 in the present embodiment.
　切替え加算部17は、図示しないフレームメモリと画像処理手段と画像選択手段(表示選択部)とを備えて構成されている。ここで、フレームメモリは、白黒スキャンコンバータ9からの断層画像データと、カラースキャンコンバータ13からの弾性画像データとを格納し、画像処理手段によって、断層画像データと弾性画像データ(伝搬速度分布の画像も含む)とを合成割合を変更して合成するものである。 The switching addition unit 17 includes a frame memory (not shown), an image processing unit, and an image selection unit (display selection unit). Here, the frame memory stores the tomographic image data from the monochrome scan converter 9 and the elastic image data from the color scan converter 13, and the tomographic image data and the elastic image data (the image of the propagation velocity distribution) are stored by the image processing means. Are also synthesized at different synthesis ratios.
　合成画像の各画素の輝度情報及び色相情報は、白黒断層画像とカラー弾性画像の各情報を合成割合で加算したものとなる。さらに、画像選択手段によって、フレームメモリ内の断層画像データと弾性画像データ及び画像処理部の合成画像データのうちから画像表示部18に表示する画像を選択する。 The luminance information and hue information of each pixel of the composite image is obtained by adding each information of the black and white tomographic image and the color elastic image at the composite ratio. Further, the image selection means selects an image to be displayed on the image display unit 18 from the tomographic image data and elasticity image data in the frame memory and the composite image data of the image processing unit.
　図6に、画像表示部18に表示される画面の一例を示す。図6では、Bモード画像、Mモード画像、せん断波画像の3種類の画像が描出されている様子を示している。図6の左半分には、Bモード画像がリアルタイムに表示され、このBモード画像上に、せん断波画像を求める位置を示す計測ライン22が表示されている状態である。 FIG. 6 shows an example of a screen displayed on the image display unit 18. FIG. 6 shows a state in which three types of images, a B-mode image, an M-mode image, and a shear wave image are drawn. In the left half of FIG. 6, a B-mode image is displayed in real time, and a measurement line 22 indicating a position for obtaining a shear wave image is displayed on the B-mode image.
　検査者は、操作卓19を用いて、方向設定部14bに指令を出して計測ライン22の位置を自由に変更できる。計測ライン22を設定することで、伝搬位置検出用の超音波21を送信するチャンネルが決定される。図6の右上半分には、計測ライン22におけるMモード画像、図6右下半分は、計測ライン22における伝搬速度分布の画像が半透明表示として描出されている様子を示している。 The inspector can freely change the position of the measurement line 22 by issuing a command to the direction setting unit 14b using the console 19. By setting the measurement line 22, a channel for transmitting the ultrasonic wave 21 for detecting the propagation position is determined. In the upper right half of FIG. 6, the M mode image in the measurement line 22 is shown, and in the lower right half of FIG. 6, the propagation velocity distribution image in the measurement line 22 is shown as a semitransparent display.
　検査者は、図6左半分に描出されるBモード画像を確認しながら検査を実施していき、せん断波画像を求めるべき断面を決定する。決定された断面に対し、計測ライン22を設定する(図6は、中央部に設定した場合)。この状態で、超音波プローブ4に取り付けられた振動体3を手動で動作させ、被検体5に対して低周波振動を印加してせん断波を発生させ、前述したようにせん断波画像を求める。 The inspector conducts the inspection while confirming the B-mode image depicted in the left half of Fig. 6, and determines the cross section for which the shear wave image is to be obtained. A measurement line 22 is set for the determined cross section (FIG. 6 shows a case where the measurement line is set at the center). In this state, the vibrating body 3 attached to the ultrasonic probe 4 is manually operated to apply a low frequency vibration to the subject 5 to generate a shear wave, and a shear wave image is obtained as described above.
　図7は、図6のBモード画像の計測ライン22上にせん断波弾性情報演算部15で求めた弾性情報を合成して表示した画面である。これにより、Bモード画像上で弾性情報が確認できるので使い勝手がよくなる。 FIG. 7 is a screen in which the elasticity information obtained by the shear wave elasticity information calculation unit 15 is synthesized and displayed on the measurement line 22 of the B-mode image in FIG. As a result, the elasticity information can be confirmed on the B-mode image, which improves usability.
　図8にせん断波による弾性情報を取得するまでのフローチャートを示す。超音波プローブ4により被検体5との間で超音波を送受するステップと、被検体5にせん断波を発生させるステップと、せん断波の伝搬情報を求めるステップと、せん断波の伝搬情報を表すせん断波画像を構成するステップと、画像表示部18に前記せん断波画像と断層画像とを対応付けて表示するステップとを含んでいる。 Fig. 8 shows a flowchart for acquiring elasticity information by shear waves. A step of transmitting and receiving ultrasonic waves to and from the subject 5 by the ultrasonic probe 4, a step of generating a shear wave in the subject 5, a step of obtaining shear wave propagation information, and a shear representing the propagation information of the shear wave A step of constructing a wave image, and a step of displaying the shear wave image and the tomographic image in association with each other on the image display unit 18.
　具体的には、検査者は、Bモード画像によって超音波診断を実施すると同時に、せん断波による弾性情報を取得する断面を計測ライン22を用いて決定する(ステップ1)。 Specifically, the inspector performs ultrasonic diagnosis using the B-mode image, and at the same time, determines a cross section for acquiring elastic information by shear waves using the measurement line 22 (step 1).
　次に検査者は、断面を決定した後、超音波プローブ4に装着されている振動体3を操作することより、被検体5に対して振動を付加する(ステップ2)。送信部2からせん断波の伝搬位置検出用の超音波21が、計測ライン22で設定した断面に向けて時間間隔をおいて複数回送信される(ステップ3)。 Next, after determining the cross section, the examiner applies vibration to the subject 5 by operating the vibrating body 3 attached to the ultrasonic probe 4 (step 2). The ultrasonic wave 21 for detecting the propagation position of the shear wave is transmitted from the transmission unit 2 a plurality of times at time intervals toward the cross section set by the measurement line 22 (step 3).
　せん断波伝搬位置検出部14は、ステップ3における送受信に基づいてせん断波の伝搬位置とせん断波の伝搬時間とを求める(ステップ4)。せん断波画像構成部16は、ステップ4で求めたせん断波の伝搬位置と伝搬時間との関係を表すせん断波画像を構成する(ステップ5)。 The shear wave propagation position detection unit 14 obtains the shear wave propagation position and the shear wave propagation time based on the transmission and reception in Step 3 (Step 4). The shear wave image constructing unit 16 constructs a shear wave image representing the relationship between the propagation position and propagation time of the shear wave obtained in Step 4 (Step 5).
　ここで、断層画像構成部8は、送受信部により受信処理された反射エコー信号に基づいてMモード画像を構成する(ステップ6)。画像表示部18には、ステップ5で構成されたせん断波画像とBモード画像とが対応付けて表示されるとともにステップ6で構成されたMモード画像が並置される(ステップ7)。 Here, the tomographic image construction unit 8 constructs an M-mode image based on the reflected echo signal received and processed by the transmission / reception unit (step 6). On the image display unit 18, the shear wave image configured in step 5 and the B mode image are displayed in association with each other, and the M mode image configured in step 6 is juxtaposed (step 7).
　さらに、せん断波弾性情報演算部15によりせん断波画像に基づいて計測ライン上の弾性率分布を演算し、画像表示部18に表示されたBモード画像に弾性率分布に対応付けて合成して表示する(ステップ8)。 Further, the elastic modulus distribution on the measurement line is calculated based on the shear wave image by the shear wave elastic information calculation unit 15, and the B mode image displayed on the image display unit 18 is combined with the elastic modulus distribution and displayed. (Step 8).
　以上説明したように、本実施形態によれば、同一の超音波プローブ4を用いて断層画像取得用の超音波20を送受信しながら走査する一方、断層画像取得用の超音波20の送受信を設定された時間間隔ごとに休止し、その休止時にせん断波の伝搬位置検出用の超音波21を被検体5の設定方向に送受信することで、断層画像を取得しながらせん断波の伝搬位置を検出することができる。これにより、断層画像取得用のプローブとせん断波の伝搬速度を計測用プローブの2つのプローブが無くても、断層画像とともに設定方向上におけるせん断波の伝搬位置と伝搬時間との関係を取得できる。せん断波の伝搬位置と伝搬時間との関係から、せん断波の伝搬速度を求めることができ、これにより、設定方向上の生体組織の硬さ又は軟らかさの弾性情報を取得できる。 As described above, according to the present embodiment, scanning is performed while transmitting and receiving the ultrasonic wave 20 for tomographic image acquisition using the same ultrasonic probe 4, while transmission and reception of the ultrasonic wave 20 for acquiring the tomographic image is set. At each specified time interval, and by transmitting and receiving the ultrasonic wave 21 for detecting the propagation position of the shear wave in the set direction of the subject 5 at the time of the pause, the propagation position of the shear wave is detected while acquiring the tomographic image be able to. Accordingly, the relationship between the propagation position of the shear wave and the propagation time in the setting direction can be acquired together with the tomographic image, even without the probe for tomographic image acquisition and the probe for measuring the propagation speed of the shear wave. From the relationship between the propagation position of the shear wave and the propagation time, the propagation speed of the shear wave can be obtained, whereby the elasticity information of the hardness or softness of the biological tissue in the set direction can be acquired.
　また、方向設定部14bを、画像表示部18に表示された図6のBモード画像上に、設定方向を示す計測ライン22を生成する計測ライン生成部を備えるように構成したので、せん断波画像を得たいラインをBモード画像を参照して決めることができる。 Further, since the direction setting unit 14b is configured to include a measurement line generation unit that generates the measurement line 22 indicating the setting direction on the B mode image of FIG. 6 displayed on the image display unit 18, the shear wave image The line you want to get can be determined by referring to the B-mode image.
　また、画像表示部18を、せん断波弾性情報演算部15により求めた弾性率分布をBモード画像に対応付けて合成して表示するように構成したので、Bモード画像上で弾性率分布を確認することが容易になり、使い勝手がよくなる。 In addition, since the image display unit 18 is configured to display the composite elastic modulus distribution obtained by the shear wave elastic information calculation unit 15 in association with the B mode image, the elastic modulus distribution is confirmed on the B mode image. Easier to use, and easier to use.
　以上、本実施形態について説明したが、本発明は、これに限らず適宜構成を変更して適用することができる。例えば、検査者は、操作卓19を用いて、図6のBモード画像に代えて弾性画像とせん断波画像とMモード画像とを並置して表示する表示方式、または、図示していないが、弾性画像とせん断波画像とBモード画像とMモード画像とを並置して表示する表示方式のいずれの表示方式も選択することができ、選択するステップを図8のフローチャートに加えることもできる。また、Bモード画像とせん断波画像のみの表示方式も構成できる。 Although the present embodiment has been described above, the present invention is not limited to this, and can be applied by appropriately changing the configuration. For example, the inspector uses the console 19 to display the elastic image, the shear wave image, and the M mode image side by side instead of the B mode image in FIG. Any display method of displaying elastic images, shear wave images, B-mode images, and M-mode images side by side can be selected, and the selection step can be added to the flowchart of FIG. In addition, a display method using only a B-mode image and a shear wave image can be configured.
　また、本実施形態では、伝搬位置検出用の超音波21は、せん断波の発生の有無によらず、Bモード画像取得時に送信するようにしているが、せん断波が発生すると、図6のMモード画像上で変化が起こるので、この変化を検知したときに、伝搬位置検出用の超音波21を送信するように構成してもよい。 Further, in the present embodiment, the ultrasonic wave 21 for detecting the propagation position is transmitted at the time of acquiring the B-mode image regardless of whether or not a shear wave is generated. Since a change occurs on the mode image, the ultrasonic wave 21 for detecting the propagation position may be transmitted when this change is detected.
　また、せん断波画像構成部16を、図6のBモード画像上で選択した領域に対応するせん断波画像を表示するように構成することもでき、図8のフローチャートにそのようなステップを加えてもよい。これにより、Bモード画像で対応する領域のせん断波画像を容易に確認することができ、使い勝手がよくなる。 Further, the shear wave image construction unit 16 can be configured to display a shear wave image corresponding to the region selected on the B-mode image of FIG. 6, and such a step is added to the flowchart of FIG. Also good. Thereby, the shear wave image of the corresponding region in the B-mode image can be easily confirmed, and the usability is improved.
　2　送信部、3　振動体、4　超音波プローブ、6　受信部、14　せん断波伝搬位置検出部、14a　ラインデータメモリ、14b　方向設定部、15　せん断波弾性情報演算部、16　せん断波画像構成部、18　画像表示部、20　断層画像取得用の超音波、21　伝搬位置検出用の超音波、22　計測ライン 2 transmission unit, 3 vibrator, 4 ultrasonic probe, 6 reception unit, 14 shear wave propagation position detection unit, 14a line data memory, 14b direction setting unit, 15 shear wave elasticity information calculation unit, 16 shear wave image configuration unit, 18 Image display unit, 20 Ultrasound for tomographic image acquisition, 21 Ultrasound for propagation position detection, 22 Measurement lines

Claims (14)

  1. 　被検体との間で超音波を送受する超音波プローブと、前記被検体にせん断波を発生させる振動体と、前記超音波プローブとの間で前記超音波の送信及び受信処理を行う送受信部と、該送受信部により受信処理された反射エコー信号に基づいて断層画像を構成する断層画像構成部とを備えた超音波診断装置であって、
    　前記送受信部によって、前記超音波を前記被検体に対して時間間隔をおいて送受信し、該送受信に基づいてせん断波の伝搬情報を求めるせん断波伝搬位置検出部と、
    　該求めたせん断波の伝搬情報を表すせん断波画像を構成するせん断波画像構成部と、前記せん断波画像と前記断層画像とを表示する画像表示部とを備えたことを特徴とする超音波診断装置。     An ultrasonic probe that transmits and receives ultrasonic waves to and from the subject, a vibrating body that generates shear waves in the subject, and a transmission and reception unit that performs transmission and reception processing of the ultrasonic waves between the ultrasonic probe and An ultrasonic diagnostic apparatus comprising a tomographic image configuration unit configured to form a tomographic image based on a reflected echo signal received and processed by the transmission / reception unit,
    A shear wave propagation position detection unit that transmits and receives the ultrasonic wave with respect to the subject at a time interval, and obtains shear wave propagation information based on the transmission and reception;
    An ultrasonic diagnosis comprising: a shear wave image constructing unit that constitutes a shear wave image representing the obtained shear wave propagation information; and an image display unit that displays the shear wave image and the tomographic image apparatus.
  2. 　前記被検体に対して前記伝搬位置検出用の超音波を送受信する方向を設定する方向設定部を備えることを特徴とする請求項1に記載の超音波診断装置。 2. The ultrasonic diagnostic apparatus according to claim 1, further comprising a direction setting unit that sets a direction in which the ultrasonic wave for detecting the propagation position is transmitted to and received from the subject.
  3. 　前記方向設定部は、前記画像表示部に表示された断層画像上に、前記方向を示す計測ラインを生成する計測ライン生成部を備えることを特徴とする請求項2に記載の超音波診断装置。 3. The ultrasonic diagnostic apparatus according to claim 2, wherein the direction setting unit includes a measurement line generation unit that generates a measurement line indicating the direction on the tomographic image displayed on the image display unit.
  4. 　前記せん断波画像構成部は、前記被検体に対する前記せん断波の深度と前記せん断波の発生からの経過時間とに基づいて前記せん断波画像を構成することを特徴とする請求項1乃至3のいずれか1項に記載の超音波診断装置。 4. The shear wave image constructing unit constructs the shear wave image based on a depth of the shear wave with respect to the subject and an elapsed time from the generation of the shear wave. The ultrasonic diagnostic apparatus according to claim 1.
  5. 　前記せん断波画像構成部は、前記画像表示部に表示された断層画像上で選択した領域に基づき前記せん断波画像を構成することを特徴とする請求項1乃至4のいずれか1項に記載の超音波診断装置。 5. The shear wave image forming unit according to claim 1, wherein the shear wave image forming unit forms the shear wave image based on a region selected on a tomographic image displayed on the image display unit. Ultrasonic diagnostic equipment.
  6. 　前記せん断波画像に基づいて弾性率分布を演算する弾性情報演算部を備えることを特徴とする請求項1乃至5のいずれか1項に記載の超音波診断装置。 6. The ultrasonic diagnostic apparatus according to claim 1, further comprising an elastic information calculation unit that calculates an elastic modulus distribution based on the shear wave image.
  7. 　前記画像表示部は、前記弾性率分布を前記断層画像に対応付けて合成して表示することを特徴とする請求項6に記載の超音波診断装置。 The ultrasonic diagnostic apparatus according to claim 6, wherein the image display unit synthesizes and displays the elastic modulus distribution in association with the tomographic image.
  8. 　前記送受信部により受信処理された反射エコー信号に基づいてMモード画像を構成するMモード画像構成部を備え、
    　前記画像表示部は、前記Mモード画像と前記断層画像と前記せん断波画像とを並置して表示することを特徴とする請求項1乃至7のいずれか1項に記載の超音波診断装置。     An M mode image configuration unit that configures an M mode image based on the reflected echo signal received and processed by the transmission / reception unit,
    8. The ultrasonic diagnostic apparatus according to claim 1, wherein the image display unit displays the M-mode image, the tomographic image, and the shear wave image side by side.
  9. 　前記送受信部は、前記Mモード画像上の変化を検知して前記伝搬位置検出用の超音波の送信を開始することを特徴とする請求項8に記載の超音波診断装置。 The ultrasonic diagnostic apparatus according to claim 8, wherein the transmission / reception unit detects a change on the M-mode image and starts transmitting the ultrasonic wave for detecting the propagation position.
  10. 　前記被検体に前記超音波プローブを介して反射エコー信号を受信処理してＲＦフレームデータを生成し、該ＲＦフレームデータから弾性画像を構成する弾性画像構成部と、
    　前記画像表示部は、前記弾性画像と前記せん断波画像とを並置して表示することを特徴とする請求項1乃至9のいずれか1項に記載の超音波診断装置。     An elastic image constructing unit configured to receive an echo signal from the subject via the ultrasonic probe to generate RF frame data, and to construct an elastic image from the RF frame data;
    10. The ultrasonic diagnostic apparatus according to claim 1, wherein the image display unit displays the elastic image and the shear wave image side by side.
  11. 　超音波プローブにより被検体との間で超音波を送受するステップと、
    　前記被検体にせん断波を発生させるステップと、
    　前記せん断波の伝搬情報を求めるステップと、
    　前記せん断波の伝搬情報を表すせん断波画像を構成するステップと、
    　画像表示部に前記せん断波画像と断層画像とを対応付けて表示するステップとを含むことを特徴とするせん断波の伝搬画像生成方法。     Sending and receiving ultrasonic waves to and from the subject with an ultrasonic probe;
    Generating shear waves in the subject;
    Obtaining propagation information of the shear wave;
    Constructing a shear wave image representing propagation information of the shear wave;
    A shear wave propagation image generation method comprising: displaying the shear wave image and the tomographic image in association with each other on an image display unit.
  12. 　前記せん断波画像に基づいて弾性率分布を演算するステップを含むことを特徴とする請求項11記載のせん断波の伝搬画像生成方法。 12. The shear wave propagation image generation method according to claim 11, further comprising a step of calculating an elastic modulus distribution based on the shear wave image.
  13. 　前記せん断波画像を構成するステップは、前記被検体に対する前記せん断波の深度と前記せん断波の発生からの経過時間とに基づいて前記せん断波画像を構成することを特徴とする請求項11記載のせん断波の伝搬画像生成方法。 12. The step of constructing the shear wave image constructs the shear wave image based on a depth of the shear wave with respect to the subject and an elapsed time from the generation of the shear wave. Shear wave propagation image generation method.
  14. 　前記被検体に対して前記超音波を送受信する方向を設定することを含むことを特徴とする請求項11記載のせん断波の伝搬画像生成方法。 12. The shear wave propagation image generation method according to claim 11, further comprising: setting a direction in which the ultrasonic wave is transmitted / received to / from the subject.
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