JP2008212548A - Ultrasonic diagnostic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic diagnostic apparatus capable of easily determining whether or not an obtained tissue property value is obtained by correct measurement. <P>SOLUTION: The ultrasonic diagnostic apparatus includes: a transmission part 102 and a reception part 103 for transmitting and receiving ultrasonic waves by an ultrasonic probe; a tomographic image processing part 104 for generating the tomographic image of a subject from reception signals; a tissue tracking part 110 for tracking the movement of each tissue of the subject from the reception signals and outputting tracking position information; a distortion calculation part 111 for calculating the distortion of object tissue from the tracking position information and generating the distribution image of the distortion; a tissue property value calculation part 112 for calculating the tissue property value from the distribution of the distortion and generating the distribution image of the tissue property value; an image composition part 106 for combining the tomographic image and the distribution image of the distortion or the distribution image of the tissue property value; and a display part 107 for displaying the combined image. The distribution image of the distortion and the tomographic image are superimposed and displayed during the transmission and reception of the ultrasonic waves, and the distribution image of the tissue property value and the tomographic image are superimposed and displayed during the stoppage of the transmission and reception of the ultrasonic waves. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to an ultrasonic diagnostic apparatus that tracks the movement of a subject tissue and obtains the elastic modulus of the subject tissue from the tracking waveform.

  The ultrasonic diagnostic apparatus irradiates a subject with ultrasonic waves and analyzes information included in the echo signal to inspect the subject non-invasively. 2. Description of the Related Art Conventionally, an ultrasonic diagnostic apparatus that has been widely used obtains the structure of a subject as a tomographic image by converting the intensity of an echo signal into the luminance of a corresponding pixel. Thereby, the internal structure of the subject can be known.

  On the other hand, in recent years, by analyzing mainly the phase of the echo signal, the movement of the tissue of the subject is accurately measured, and physical (property) characteristics such as tissue distortion, elastic modulus, and viscosity are obtained. Has been tried.

Patent Document 1 uses a phase difference between ultrasonic echo signals transmitted and received at regular intervals to obtain an instantaneous amount of movement of a local region of the subject, and adds the amount of movement to the subject tissue. Discloses a method for tracking the image with high accuracy. The subject tissue tracking method disclosed in Patent Document 1 will be described with reference to FIG. Ultrasonic pulses are transmitted at intervals of ΔT toward the same part of the subject, and received signals obtained by converting the obtained reflected echoes into electrical signals are y (t) and y (t + ΔT), respectively. t is the reception time with the transmission time set to 0. The relationship of the following formula (1) is established between the echo signal obtained from a measurement point located at a certain distance (depth) x from the probe and the reception time tx, where C is the speed of sound.
tx = x / (C / 2) (1)

At this time, if the phase difference between y (tx) and y (tx + ΔT) is Δθ, and the center frequency of the ultrasonic wave in the vicinity of tx is f, the movement amount Δx of the measurement point in this period ΔT is expressed by the following equation ( 2).
Δx = −C · Δθ / 4πf (2)

By adding the movement amount ΔX obtained from the equation (2) to the original measurement point position x, the position x ′ after ΔT of the measurement point is obtained by the following equation (3).
x ′ = x + Δx (3)

  By repeating this calculation, the position of the measurement point in the subject can be tracked. For example, assuming that the reception time of the echo reflected from the position x ′ is tx ′ and the received signal transmitted and received subsequently is y (t + 2ΔT), the phase difference between y (tx ′ + ΔT) and y (tx ′ + 2ΔT) Thus, the position x ″ of the measurement point after 2ΔT can be obtained by the calculations of the equations (1) and (2).

  Patent Document 2 discloses a method of further developing the method of Patent Document 1 and obtaining the elastic modulus of a subject tissue, particularly an arterial blood vessel wall. According to this method, first, as shown in FIG. 10A, ultrasonic waves are transmitted from the probe 101 toward the blood vessel 222 of the subject 230, and the measurement point A set on the blood vessel wall of the blood vessel 222 is measured. The movement of the measurement points A and B is tracked by analyzing the echo signals from A and B by the method of Patent Document 1. FIG. 10B shows tracking waveforms TA and TB at measurement points A and B. An electrocardiographic waveform ECG is also shown.

  As shown in FIG. 10B, the tracking waveforms TA and TB have a periodicity that matches the electrocardiogram waveform ECG. This indicates that the artery expands and contracts in line with the heart cycle of the heart. Specifically, when a large peak called an R wave is seen in the electrocardiogram waveform ECG, the contraction of the heart starts, and the blood flow is pushed into the artery due to the contraction of the heart, thereby increasing the blood pressure. The blood vessel wall is rapidly expanded by this blood pressure. Therefore, after the R wave appears in the electrocardiogram waveform ECG, the artery expands rapidly, and the tracking waveforms TA and TB also rise rapidly. Thereafter, as the heart slowly expands, the artery contracts slowly, and the tracking waveforms TA and TB gradually return. The artery repeats this movement.

The difference between the tracking waveforms TA and TB is a thickness change waveform W between the measurement points AB. When the maximum change amount of the thickness change waveform W is ΔW and the reference thickness at the time of initialization between the measurement points AB (end diastole) is Ws, the maximum strain amount ε between the measurement points AB is expressed by the following equation (4 ).
ε = ΔW / Ws (4)

Since this distortion is due to a blood pressure difference applied to the blood vessel wall, assuming that the blood pressure difference at this time is ΔP, the elastic modulus Er between the measurement points AB is expressed by the following equation.
Er = ΔP / ε = ΔP · Ws / ΔW (5)

  Therefore, an elastic modulus distribution image can be obtained by measuring the elastic modulus Er with respect to a plurality of points on the tomographic image.

  As shown in FIG. 10A, when an edema 220 is generated in the blood vessel wall of the blood vessel 222, the elastic modulus is different between the atheroma 220 and the surrounding blood vessel wall tissue. Therefore, if an elastic modulus distribution image is obtained, important information for diagnosing the nature of the atheroma, particularly easily ruptured, can be obtained.

  The elastic modulus obtained in this way is called the radial elastic modulus of the blood vessel. In addition to the radial elastic modulus Er, the blood vessel wall having a cylindrical shape has three types of elastic modulus: a circumferential elastic modulus Eθ and an axial elastic modulus Ez. The elastic modulus Er obtained by Patent Document 2 is the elastic modulus in the radial direction of the blood vessel wall, and the strain of the blood vessel wall is detected in the radial direction of the blood vessel wall, which is the direction in which pressure is applied, and the elastic modulus is calculated from the strain and pressure. Is calculated.

Non-Patent Document 1 discloses a method of calculating the elastic modulus Eθ in the circumferential direction of the blood vessel wall. According to Non-Patent Document 1, since the blood vessel wall has a concentric three-layer structure, the circumferential elastic modulus Eθ more accurately reflects the tissue property of the blood vessel wall than the radial elastic modulus Er. Non-Patent Document 1 obtains the circumferential elastic modulus Eθ using the following equation (5). Here, h0 is the initial radial thickness of the blood vessel wall, and r0 is the initial radius of the blood vessel.
Eθ = − (1/2) (r0 / h0 + 1) (ΔP / ε) (5)

Further, the viscosity μ shown in the following formula described in Non-Patent Document 2 is also an important index indicating the tissue properties of the blood vessel wall.
P = μdε / dt + Eε (6)

  It is also important for the ultrasonic diagnostic apparatus to display the tissue property characteristic values such as the elastic modulus and the viscosity obtained in this manner in an easy-to-see manner. Patent Document 3 discloses an ultrasonic diagnostic apparatus that displays a blood flow portion of a black and white tomographic image in a color tone according to a blood flow velocity and displays a tissue portion in another color tone according to a tissue property value. Also, two tomographic images are displayed on the screen, the blood flow part of one tomographic image is displayed in a color tone according to the blood flow velocity, and the tissue part of the other tomographic image is displayed in another color tone according to the tissue property value. Discloses an ultrasonic diagnostic apparatus. This makes it easy to understand the relationship between blood flow, tissue properties, and tomographic images, and can accurately diagnose lesions in in vivo tissues.

Japanese Patent Laid-Open No. 2004-228561 analyzes the velocity fluctuation of the blood flow, identifies whether the blood flow is a pulsating wave, a stationary wave, or no flow, generates a color image, and switches to a conventional blood flow color image for display. An ultrasonic diagnostic apparatus is disclosed.
Japanese Patent Laid-Open No. 10-5226 JP 2000-229078 A JP-A-6-292670 JP-A-5-261100 Hasegawa, Kanai et al. “Measurement of local elastic modulus of pipes with non-uniform wall thickness” J Med Ultrasonics Vol.28, No.1 (2001) pp.J3-J13 Hiroshi Kanai "Spectral analysis of sound and vibration" Corona, ISBN 4-339-01105-3, edited by the Acoustical Society of Japan

  Tissue property values such as elastic modulus and viscosity are determined by the amount of strain of the tissue and the pressure that gives strain to the tissue. However, since these values are measured independently, if the tissue property value is abnormal, it is difficult to determine from the tissue property value whether the cause is the strain amount or the pressure. If the cause cannot be identified, it is difficult to perform correct measurement.

  An object of the present invention is to provide an ultrasonic diagnostic apparatus that can easily determine whether or not the obtained tissue property value is obtained by correct measurement.

  An ultrasonic diagnostic apparatus according to the present invention includes a transmitter that drives an ultrasonic probe to transmit an ultrasonic wave to a subject, and an ultrasonic echo obtained by reflecting the ultrasonic wave on the subject. A reception unit that receives the ultrasonic probe and generates a reception signal, a tomographic image processing unit that generates a tomographic image of the subject from the reception signal, and each of the subject from the reception signal From the tissue distribution unit that tracks the movement of the tissue and outputs tracking position information, calculates the strain of the subject tissue from the tracking position information, and generates a strain distribution image, and the strain distribution A tissue property value calculating unit that calculates a tissue property value and generates a distribution image of the tissue property value; an image composition unit that combines the tomographic image and the strain distribution image or the distribution image of the tissue property value; Display the synthesized image A display unit, and during transmission and reception of ultrasonic waves by the transmission unit and the reception unit, the distortion distribution image and the tomographic image are superimposed and displayed by combining the distortion distribution image and the tomographic image, While the transmission / reception of the ultrasonic wave is stopped, the tissue property value distribution image and the tomographic image are combined to display the tissue property value distribution image and the tomographic image.

  In a preferred embodiment, the ultrasonic diagnostic apparatus further includes a storage unit that stores data of the tomographic image and data of the distribution image of the tissue property value, and during the transmission / reception of the ultrasonic wave, the storage unit Storing image data and data of the distribution image of the tissue property value, and stopping the transmission / reception of the ultrasound, the distribution image data of the tissue property value and the tomographic image corresponding to the distribution image of the tissue property value Data is read from the storage unit, and the distribution image of the tissue property value is displayed superimposed on the tomographic image.

  In a preferred embodiment, the ultrasonic diagnostic apparatus further includes a storage unit that stores data of the tomographic image and data of the distribution image of the tissue property value, and during the transmission / reception of the ultrasonic wave, the storage unit Storing image data and data of the tissue property value distribution image, and stopping the transmission / reception of the ultrasonic wave, the tomographic image data and the tissue property value distribution image data corresponding to the tomographic image; Reading from the storage unit and displaying the distribution image of the tissue property value superimposed on the tomographic image.

  In a preferred embodiment, the image synthesizing unit superimposes and displays the tomographic image and the strain distribution image or the tissue property value distribution image on the second region of the display unit, and Image data for displaying a tomographic image in which the strain distribution image and the tissue property value distribution image are not superimposed on the first region of the display unit is generated.

  In a preferred embodiment, the image composition unit generates an image for displaying a cursor at a position indicated by an operator of the display unit, and the cursor is on a second region or while the transmission / reception of the ultrasonic wave is stopped. If it is in the vicinity thereof, the tissue property value distribution image data and the tomographic image data corresponding to the tissue property value distribution image are read from the storage unit, and the tissue property value distribution image is read from the storage unit. Superimposed on a tomographic image.

  In a preferred embodiment, the image composition unit generates an image for displaying a cursor at a position indicated by an operator on the display unit, and the cursor is on a second region or while the transmission / reception of the ultrasonic wave is stopped. If it is in the vicinity thereof, the tomographic image data and the distribution data of the tissue property value corresponding to the tomographic image are read from the storage unit, and the distribution image of the tissue property value is converted into the tomographic image. Superimposed display.

  In a preferred embodiment, the storage unit stores data of the distortion distribution image, and the image synthesis unit generates an image that displays a cursor at a position indicated by an operator of the display unit, and When the transmission / reception of the sound wave is stopped, when the cursor is on or near the first area, the distortion distribution image data and the tomographic image data corresponding to the distortion distribution image are stored. The distortion distribution image is superimposed on the tomographic image and displayed.

  In a preferred embodiment, the storage unit stores data of the distortion distribution image, and the image synthesis unit generates an image that displays a cursor at a position indicated by an operator of the display unit, and While the transmission / reception of sound waves is stopped, when the cursor is on or near the first region, the tomographic image data and the distortion distribution image data corresponding to the tomographic image are stored from the storage unit. Read and display the distortion distribution image superimposed on the tomographic image.

  In a preferred embodiment, during the transmission / reception of the ultrasonic wave, the distribution image of the tissue property value is switched to the distribution image of the distortion and displayed superimposed on the tomographic image based on an operator's command.

  In a preferred embodiment, while the transmission / reception of the ultrasonic wave is stopped, the strain distribution image is switched with the tissue property value distribution image and displayed superimposed on the tomographic image based on an operator command.

  In a preferred embodiment, based on an operator's command, the previous distortion distribution image and the tomographic image are displayed in a superimposed manner, or the tissue property value distribution image and the tomographic image are superimposed. Only the tomographic image is displayed in the displayed state.

  According to the ultrasonic diagnostic apparatus of the present invention, while transmitting and receiving ultrasonic waves and performing measurement, a distortion distribution image is superimposed on the tomographic image and displayed. For this reason, it is possible to determine whether or not the position of each tissue of the subject is correctly tracked during measurement. Therefore, it can be easily determined whether or not the measurement is highly reliable.

  Hereinafter, embodiments of an ultrasonic diagnostic apparatus according to the present invention will be described. FIG. 1 shows a block diagram of an embodiment of an ultrasonic diagnostic apparatus according to the present invention. The ultrasonic diagnostic apparatus includes a transmission unit 102, a reception unit 103, a tomographic image processing unit 104, an image synthesis unit 106, a tissue tracking unit 110, a distortion calculation unit 111, a monitor 107 that functions as a display unit, a tomographic image memory 120, and a distortion image. A memory 121, an elastic modulus memory 122, a control unit 100, and a user interface 125 are provided.

  The control unit 100 controls each component of the ultrasonic diagnostic apparatus. The user interface 125 includes a keyboard, a trackball, a switch, a button, and the like, and inputs an operator command related to the operation of the ultrasonic diagnostic apparatus to the control unit 100. In addition, as described below, the cursor is displayed on the monitor 107, and the operator moves the cursor to a desired position by the user interface 125, whereby the position information of the cursor on the image displayed on the monitor 107 is displayed. Can be obtained.

  In response to an instruction from the control unit 100, the transmission unit 102 generates a high-voltage signal that drives the probe 101 at a designated timing. The probe 101 converts the transmission signal generated by the transmission unit 102 into an ultrasonic wave and irradiates the subject.

  The receiving unit 103 detects an ultrasonic echo reflected from the inside of the subject by the probe 101 and converts it into an electrical reception signal. A plurality of electroacoustic transducers are arranged in the probe 101. The deflection angle of ultrasonic waves to be transmitted / received by selecting the electroacoustic transducers used for transmission / reception and adjusting the timing for applying voltage to the electroacoustic transducers. And control the focus. The receiving unit 103 amplifies the received signal and adds a predetermined delay to the received signal received by each electroacoustic transducer, thereby adding the signal from a specific position (focus) or direction (deflection angle). Only detect ultrasound. Transmission / reception of ultrasonic waves is generally performed from dozens to several tens of times per second.

  The tomographic image processing unit 104 includes a filter, a detector, a logarithmic amplifier, and the like. The tomographic image processing unit 104 analyzes mainly the amplitude of the received signal and images the internal structure of the subject as a tomographic image. Since a tomographic image is generated each time a reception signal is received, the tomographic image is generally updated from several tens to several tens of times per second.

  The tissue tracking unit 110 is a memory that stores reception signals, a movement amount calculation unit that calculates a movement amount of the subject tissue along the ultrasonic wave transmission / reception direction using the equation (1) from the phase difference between the reception signals. As shown in Expression (2), the position tracking calculation unit that adds the movement amount to the original position and obtains the position after the movement is obtained, and tracks and tracks the movement of the subject tissue in the direction of ultrasonic transmission / reception. Calculate location information. The tracking position information is generally updated every time a received signal is received, that is, from dozens to several tens of times per second.

  The distortion calculation unit 111 calculates the distortion shown in Expression (3) from the tracking position information of the plurality of measurement points of the subject tissue obtained by the tissue tracking unit 110, and images the distribution. The distortion distribution image is also updated every time a received signal is received, that is, ten to several tens of times per second.

  The ultrasonic diagnostic apparatus receives information on the force or pressure that causes the subject tissue to be deformed from the force or pressure acquisition unit 113. For example, when the subject includes an arterial blood vessel wall and the elastic modulus of the blood vessel wall is measured, it is a pressure change of blood flowing through the blood vessel that causes the deformation of the blood vessel wall. Therefore, it is preferable to use a sphygmomanometer as the force or pressure acquisition unit 113 and receive information related to blood pressure. Further, the operator may input the blood pressure value using the user interface 125. The subject may be a stationary organ. In this case, the stationary organ is deformed by applying pressure or vibration from the outside, and the elastic modulus is measured. The force or pressure acquisition unit 113 is a pressure gauge that measures the pressure applied to the subject from the outside.

  The tissue property value calculation unit 112 calculates an elastic modulus from the strain obtained by the strain calculation unit 111 and the force or pressure value obtained by the force or pressure acquisition unit 113, and images the distribution. When a blood vessel is a measurement target, the elastic modulus is a radial elastic modulus shown in Equation (4) or a circumferential elastic modulus as shown in Equation (5). Further, in addition to the elastic modulus or instead of the elastic modulus, the viscosity shown in the equation (6) may be obtained.

  When the elastic modulus of the arterial blood vessel wall is measured according to the equations (4) and (5), for example, the elastic modulus is obtained using the difference between the maximum blood pressure value and the minimum blood pressure value during one cardiac cycle. Therefore, the elastic modulus distribution image is created and updated for each heartbeat. When pressure or vibration is applied from the outside, the elastic modulus is updated for each period of pressure or vibration applied from the outside.

  The image synthesizing unit 106 synthesizes the tomographic image and one or both of the strain image and the elastic modulus distribution image, and displays the synthesized image on the monitor 107. The image synthesis unit 106 may further synthesize the synthesized image with a biological signal waveform such as ECG, a graphic character such as a character, a numerical value, a cursor, an ROI frame, or a scale. The tomographic image memory 120, the strain image memory 121, and the elastic modulus image memory 122 store tomographic image data, strain image data, and elastic modulus data, respectively.

  In the embodiment of the present invention, the block diagram is shown as an independent block diagram in FIG. 1. However, the present invention is not limited to this. For example, the control unit 100, tomographic image processing unit 104, tissue tracking unit 110, strain calculation unit 111, tissue The property value calculation unit 112, the image composition unit 106, and the like may be realized as software executed on the CPU.

  The operation of the ultrasonic diagnostic apparatus configured as described above will be described with reference to FIGS.

  2 to 5 are screens of the monitor 107 displaying an example of the result of measuring the elastic modulus, which is a value representing the tissue properties of the blood vessel wall, in the axial direction of the blood vessel wall 222 having the atheroma 220 on the screen. The measurement screen of a parallel section is shown. 6 to 8 are flowcharts showing the operation of the ultrasonic diagnostic apparatus.

  First, an operation while transmitting and receiving ultrasonic waves and performing measurement (also referred to as a live state) will be described.

  As shown in FIG. 6, the ultrasound diagnostic apparatus transmits and receives ultrasound (S101), and sequentially acquires received signals. The tissue tracking unit 110 receives the received signal and sequentially calculates the position information of the subject tissue (S102). The strain calculation unit 111 obtains tissue strain from the position information, and further sequentially generates strain distribution images (S104). In addition, the tomographic image processing unit 104 sequentially generates tomographic images from the received signals. The tomographic image and the distortion distribution image generated in this way are combined by the image combining unit 106 and displayed on the monitor 107.

  FIG. 2 shows an example of the screen of the monitor 107 during measurement. As shown in FIG. 2, a strain distribution image 201 is superimposed and displayed at the same position on the tomographic image 200. The tomographic image 200 is updated from dozens to several tens of times per second, as in a normal ultrasonic diagnostic apparatus, and the distortion image 201 is also updated from dozens to several tens of times per second. The update periods of the distorted image 201 and the tomographic image 200 are usually the same but may be different.

  As shown in FIG. 2, a tomographic reflection intensity scale 210 indicating correspondence between the received signal and the luminance of the tomographic image, a distortion image distortion scale 211 indicating the correspondence between the magnitude and color tone of the distortion, and a biological signal waveform such as an electrocardiographic waveform. 214 and the like are also displayed. The data of the tomographic image 200 and the data of the distorted image 201 are stored in the tomographic image memory 120 and the distorted image memory 121, respectively (S108, S106).

  Although not displayed during measurement, the tissue property value calculation unit 112 calculates the elastic modulus from the strain of the tissue and generates a distribution image of the elastic modulus. The generated elastic modulus distribution image data is stored in the elastic modulus image memory 122 (S109). As described above, the elastic modulus distribution image is generated once per heartbeat.

  As described above, the ultrasonic diagnostic apparatus of the present embodiment displays the strain distribution image while sequentially updating in real time during measurement. For this reason, it is possible to determine whether the position of each tissue in the subject can be correctly tracked during measurement.

  When the transmission / reception of the ultrasonic wave is stopped, that is, when the measurement is completed or interrupted (also referred to as the freeze state), the image data stored in the memory is read and displayed on the monitor 107. As shown in FIG. 7, first, the latest elastic modulus distribution image data is read from the elastic modulus image memory 122 (S111), and the tomographic image corresponding to the latest elastic modulus distribution image is read from the tomographic image memory 120. Data is read (S112). These image data are combined (S113) and displayed on the monitor 107.

  Here, “correspondence” refers to correspondence at the same time or time. It is also said that the time phases are the same. When the distribution image of the elastic modulus of the arterial blood vessel wall is obtained based on the maximum blood pressure value and the minimum blood pressure value, the elastic modulus distribution image is generated once during one cardiac cycle. This image is based on systolic and diastolic blood pressure values during a cardiac cycle and the maximum strain of tissue during a cardiac cycle. Therefore, if the tomographic image is obtained in the same cardiac cycle as the elastic modulus distribution image, it can be said that it corresponds temporally. Generally, in order to synchronize the cardiac cycle with an electrocardiogram, a tomographic image that matches the timing of the R wave in the same cardiac cycle may be selected.

  FIG. 3 shows an example of the screen of the monitor 107 in a state where the measurement is completed or interrupted. The latest elastic modulus distribution image 202 and the corresponding tomographic image 200 are superimposed and displayed. Furthermore, a tomographic image reflection intensity scale 210 indicating the correspondence between the received signal and the luminance of the tomographic image, an elastic modulus distribution image elastic modulus scale 212 indicating the correspondence between the elastic modulus and color, a biological signal waveform 214 such as an electrocardiographic waveform, etc. Is also displayed.

  When the measurement is completed or interrupted, images acquired in the past can be read from the memories 120 to 122 one after another and displayed. Since only one elastic modulus distribution image 202 is generated for one heartbeat, the elastic modulus distribution image 202 is read from the elastic modulus image memory 122 one by one, and only the tomographic image 200 corresponding to the elastic modulus distribution image 202 is tomographically read out. The image is selected from the image memory 120 and read out, and the elastic modulus distribution image 202 is superimposed on the tomographic image 200 and displayed.

  Alternatively, the tomographic images 200 are read one by one from the tomographic image memory 120, the elastic modulus distribution image 201 calculated from the heartbeat including the tomographic image 200 is read from the elastic modulus image memory 122, and the elastic modulus is displayed on the tomographic image 200. The distribution image 202 may be superimposed and displayed.

  In the above-described embodiment, only the image in which the strain distribution image or the elastic modulus distribution image is superimposed on the tomographic image is displayed on the monitor 107. However, a two-screen mode display that separately displays only the tomographic image is adopted. Also good.

  4 and 5 show an example of the screen of the monitor 107 during measurement when displaying in the two-screen mode, and an example of the screen of the monitor 107 in a state where the measurement is completed or interrupted.

  The operation during the measurement is as described with reference to FIG. As shown in FIG. 4, only the tomographic image 203 is displayed in the first region 203 ′, and the strain distribution image 201 is superimposed on the tomographic image 204 and displayed in the second region 204 ′. The tomographic image 203 and the tomographic image 204 are the same. The tomographic image 203 and the tomographic image 204 are updated from dozens to several tens of times per second, as in a normal ultrasonic diagnostic apparatus, and the strain distribution image 201 is also updated from ten to several tens of times per second.

  Also displayed are a tomographic reflection intensity scale 210 indicating the correspondence between the received signal and the luminance of the tomographic image, a distortion image distortion scale 211 indicating the correspondence between the distortion and the color tone, and a biological signal waveform 214 such as an electrocardiographic waveform. . The tomographic images 203 and 204 are stored in the tomographic image memory 120, and the distorted image 201 is stored in the distorted image memory 121. Although not displayed in the live state, the tissue property value calculation unit 112 also generates an elastic modulus distribution image and stores it in the elastic modulus image memory 122. An elastic modulus distribution image is generated once per heartbeat.

  When the measurement is completed or interrupted, as shown in FIG. 5, only the tomographic image 203 is displayed in the first area 203 ′ of the monitor 107 and the tomographic image 204 is displayed in the second area 204 ′. The elastic modulus distribution image 202 is superimposed and displayed. Except for displaying only the tomographic image 203 in the first region 203 ', the display shown in FIG. 5 can be performed by the same procedure as that shown in FIG.

  Further, by utilizing the display of two tomographic images, the elastic modulus distribution image and the strain distribution image may be switched and displayed. Specifically, as shown in FIGS. 5 and 8, first, the latest tomographic image data is read from the tomographic image memory 120, and the latest tomographic image is stored in the first region 203 ′ and the second region 204 ′. It is displayed (S121). Data of the elastic modulus distribution image corresponding to the displayed tomographic image is read out from the elastic modulus image memory 122, and the elastic modulus distribution image 202 is superimposed and displayed on the tomographic image 204 located in the second region 204 ′. Also good. In addition, a cursor 215 that can be moved by the operator using the user interface 125 is displayed on the screen of the monitor 107.

  The control unit 100 acquires the position of the cursor 215 (S122), and determines whether the cursor 215 is positioned on or near the first region 203 '(S123). When the cursor 215 is on or near the first region 203 ′, the tomographic image data is read from the tomographic image memory 120 one by one (S125), and the elastic modulus distribution image data corresponding to the tomographic image is read. It selects and reads from the elastic modulus image memory 122 (S126). The image data is synthesized so that only the tomographic image is displayed in the first region 203 ′ and the elastic modulus distribution image 202 is superimposed on the tomographic image 204 in the second region 204 ′ and displayed on the monitor 107. (S127). At this time, the second tomographic image 204 may always be a tomographic image corresponding to the elastic modulus distribution image 202.

  If the cursor 215 is not on or near the first region 203 ', it is determined whether the cursor 215 is located on or near the second region 204' (S124). When the cursor 215 is on or near the second region 204 ′, the elastic modulus distribution image is read from the elastic modulus image memory 122 (S128), and only the tomographic image corresponding to the read elastic modulus distribution image is read. It selects and reads from the tomographic image memory 120 (S129). The image data is synthesized so that only the tomographic image is displayed in the first region 203 ′ and the elastic modulus distribution image 202 is superimposed on the tomographic image 204 in the second region 204 ′ and displayed on the monitor 107. (S130). At this time, in the first region 203 ′, a plurality of tomographic images in the cardiac cycle from which the elastic modulus distribution image displayed in the second region 024 ′ is sequentially read out from the tomographic image memory 120 and displayed. May be.

  If the cursor is neither in the first area 203 'nor in the second area 204', it waits until the cursor position is acquired (S122) in order to wait for input from the operator.

  When the cursor is in the first region 203 ', a distortion distribution image may be displayed in the second region 204'. In this case, for example, the tomographic image data is read from the tomographic image memory 120 one by one, and the distortion distribution image data corresponding to the tomographic image is read from the distorted image memory 121. Image data is synthesized so that only the tomographic image is displayed in the first area 203 ′ and the distortion distribution image is displayed in the second area 204 ′ superimposed on the tomographic image 204, and displayed on the monitor 107.

  Alternatively, when the cursor is in the first region 203 ′, distortion distribution images may be read from the distortion image memory 121 one by one, and tomographic image data corresponding to the distortion distribution image may be read from the tomographic image memory 120. Good.

  In general, a tomographic image and a strain distribution image are created each time a received signal is received, so the tomographic image and the strain distribution image are synchronized in time. However, if they are not synchronized, the other image temporally corresponding to the tomographic image or the strain distribution image may be read from the memory and displayed.

  As described above, according to the ultrasonic diagnostic apparatus of the present invention, while transmitting and receiving ultrasonic waves and performing measurement, a strain distribution image is superimposed on the tomographic image and displayed. For this reason, it is possible to determine whether or not the position of each tissue of the subject is correctly tracked during measurement. Specifically, it is possible to easily determine that correct measurement is not possible due to large body movement of the subject or that the contact state between the probe and the subject is not good. Become. In addition, when the strain distribution image is obtained correctly but the elastic modulus distribution image is inappropriate, it can be determined that the force or pressure acquisition unit cannot correctly measure the force or pressure. .

  Therefore, after confirming that the correct measurement is performed, the measurement data can be stored, and the time when the correct measurement can be performed can be recorded. When displaying the elastic modulus distribution image after the measurement is completed, display the elastic modulus distribution image only during the correct measurement period, or obtain the elastic modulus distribution image accurately. Can be easily recognized.

  In the above embodiment, the distortion distribution image is superimposed on the tomographic image and displayed during measurement. However, the distortion distribution image does not always have to be displayed, and an operator command using the user interface 125 is not necessary. Thus, an elastic modulus distribution image may be displayed. Further, after the measurement is completed or interrupted, the elastic modulus distribution image is displayed superimposed on the tomographic image. However, the elastic modulus distribution image does not always need to be displayed, and the operation using the user interface 125 is performed. A distortion distribution image may be displayed according to a user's instruction.

  Further, as shown in FIGS. 3 and 4, when only the tomographic image on which the strain distribution image or the elastic modulus distribution image is superimposed is displayed on the monitor 107, the strain distribution image or the elastic modulus distribution image is always displayed. It is not necessary to display, and a state in which a strain distribution image or an elastic modulus distribution image is not displayed may be selected according to an instruction from an operator using the user interface 125. As a result, the shape of the tissue displayed by the tomographic image can be easily associated with a value representing strain or elastic modulus.

  Moreover, in the said embodiment, although the elasticity modulus was calculated | required as a structure | tissue property value, you may obtain | require a viscosity instead of or in addition to an elasticity modulus according to Formula (6).

  The present invention is suitably used for an ultrasonic diagnostic apparatus capable of measuring a tissue property value of a subject.

1 is a block diagram showing an embodiment of an ultrasonic diagnostic apparatus according to the present invention. It is a figure which shows an example of the monitor screen during measurement of the ultrasonic diagnosing device shown in FIG. It is a figure which shows an example of the monitor screen after completion | finish of a measurement of the ultrasonic diagnosing device shown in FIG. It is a figure which shows the other example of the monitor screen during measurement of the ultrasonic diagnosing device shown in FIG. It is a figure which shows the other example of the monitor screen after the measurement completion | finish of the ultrasonic diagnosing device shown in FIG. It is a flowchart which shows the operation | movement procedure during measurement of the ultrasonic diagnosing device shown in FIG. It is a flowchart which shows the operation | movement procedure after completion | finish of a measurement of the ultrasonic diagnosing device shown in FIG. 6 is a flowchart showing another operation procedure after the measurement of the ultrasonic diagnostic apparatus shown in FIG. It is a figure which shows the principle which tracks the position of a structure | tissue from a phase difference. (A) explains the procedure for measuring a blood vessel wall using an ultrasonic diagnostic apparatus. (B) shows an example of a tracking waveform and a thickness change waveform obtained by measurement.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Control part 101 Probe 102 Transmission part 103 Reception part 104 Tomographic image processing part 106 Image composition part 107 Monitor 110 Tissue tracking part 111 Distortion calculation part 112 Tissue property value calculation part 113 Force or pressure acquisition part 120 Tomographic image memory 121 Distortion Image memory 122 Elastic modulus image memory 200 Tomographic image 201 Strain distribution image 202 Elastic modulus distribution image 203, 204 Tomographic image 203 'First region 204' Second region 210 Reflection intensity scale for tomographic image 211 Strain for distortion image Scale 212 Elastic modulus scale for elastic modulus distribution image 214 Biological signal waveform 215 Cursor

Claims (11)

A transmitter that drives an ultrasonic probe to transmit ultrasonic waves to the subject;
A receiving unit that receives an ultrasonic echo obtained by reflecting the ultrasonic wave at the subject using the ultrasonic probe, and generates a reception signal;
A tomographic image processing unit for generating a tomographic image of the subject from the received signal;
A tissue tracking unit that tracks the movement of each tissue of the subject from the received signal and outputs tracking position information;
A strain calculator that calculates strain of the subject tissue from the tracking position information and generates a strain distribution image;
A tissue property value calculating unit that calculates a tissue property value from the strain distribution and generates a distribution image of the tissue property value;
An image synthesis unit that synthesizes the tomographic image and the strain distribution image or the tissue property value distribution image;
A display unit for displaying the synthesized image;
With
During transmission / reception of ultrasonic waves by the transmission unit and the reception unit, the distortion distribution image and the tomographic image are superimposed and displayed by synthesizing the distortion distribution image and the tomographic image,
An ultrasonic diagnostic apparatus that superimposes and displays the tissue property value distribution image and the tomographic image by combining the tissue property value distribution image and the tomographic image while the transmission / reception of the ultrasonic waves is stopped. A storage unit for storing data of the tomographic image and data of the distribution image of the tissue property value;
During transmission / reception of the ultrasonic wave, the storage unit stores the data of the tomographic image and the data of the distribution image of the tissue property value,
While the transmission / reception of the ultrasonic wave is stopped, the tissue property value distribution image data and the tomographic image data corresponding to the tissue property value distribution image are read from the storage unit,
The ultrasonic diagnostic apparatus according to claim 1, wherein the distribution image of the tissue property value is displayed superimposed on the tomographic image. A storage unit for storing data of the tomographic image and data of the distribution image of the tissue property value;
During transmission / reception of the ultrasonic wave, the storage unit stores the data of the tomographic image and the data of the distribution image of the tissue property value,
While the transmission / reception of the ultrasonic wave is stopped, the tomographic image data and the distribution data of the tissue property value corresponding to the tomographic image are read from the storage unit,
The ultrasonic diagnostic apparatus according to claim 1, wherein the distribution image of the tissue property value is displayed superimposed on the tomographic image.   The image synthesizing unit is configured to superimpose and display the tomographic image and the strain distribution image or the tissue property value distribution image in the second region of the display unit, and the first of the display unit The ultrasonic diagnostic apparatus according to claim 2, wherein image data for displaying a tomographic image in which the distribution image of the distortion and the distribution image of the tissue property value are not superimposed on the region is generated. The image composition unit generates an image for displaying a cursor at a position indicated by an operator of the display unit,
While the transmission / reception of the ultrasonic wave is stopped, when the cursor is on or near the second region, the distribution image data of the tissue property value and the tomographic image corresponding to the distribution image of the tissue property value are displayed. Data from the storage unit,
The ultrasonic diagnostic apparatus according to claim 4, wherein the distribution image of the tissue property value is displayed superimposed on the tomographic image. The image composition unit generates an image for displaying a cursor at a position indicated by an operator in the display unit,
While the transmission / reception of the ultrasonic wave is stopped, when the cursor is on or near the first region, the data of the tomographic image and the data of the distribution image of the tissue property value corresponding to the tomographic image are displayed. Read from the storage unit,
The ultrasonic diagnostic apparatus according to claim 4, wherein the distribution image of the tissue property value is displayed superimposed on the tomographic image. The storage unit stores data of the distribution image of the distortion,
The image composition unit generates an image for displaying a cursor at a position indicated by an operator of the display unit,
While the transmission / reception of the ultrasonic wave is stopped, when the cursor is on or near the second area, the distortion distribution image data and the tomographic image data corresponding to the distortion distribution image are displayed. Read from the storage unit,
The ultrasonic diagnostic apparatus according to claim 4, wherein the distortion distribution image is displayed superimposed on the tomographic image. The storage unit stores data of the distribution image of the distortion,
The image composition unit generates an image for displaying a cursor at a position indicated by an operator of the display unit,
When the transmission / reception of the ultrasonic wave is stopped, when the cursor is on or near the first region, the tomographic image data and the distortion distribution image data corresponding to the tomographic image are stored. Read from the
The ultrasonic diagnostic apparatus according to claim 4, wherein the distortion distribution image is displayed superimposed on the tomographic image.   The super image according to any one of claims 1 to 8, wherein during transmission / reception of the ultrasonic wave, the distribution image of the tissue property value is switched with the distribution image of the distortion and superimposed on the tomographic image based on an operator's command. Ultrasonic diagnostic equipment.   10. The distortion distribution image is switched to the tissue property value distribution image and displayed on the tomographic image while being superposed on the tomographic image based on an operator's instruction while the ultrasonic wave is being transmitted / received. The ultrasonic diagnostic apparatus as described.   In a state in which the previous strain distribution image and the tomographic image are superimposed and displayed based on an operator's command, or in a state in which the tissue property value distribution image and the tomographic image are superimposed and displayed. The ultrasonic diagnostic apparatus according to claim 1, wherein only the tomographic image is displayed.