JP2006325704A - Ultrasonic diagnostic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic diagnostic apparatus capable of accurately tracking a two-dimensional movement of a subject tissue.
An ultrasound diagnostic apparatus h includes a probe 101, a transmission unit 102, and a reception unit 103 that transmit and receive ultrasonic waves with at least two different deflection angles with respect to a measurement point set in a subject. The movement amount calculation unit 111 for obtaining the movement amount of the measurement point along the ultrasonic transmission / reception direction and the two-dimensional or three-dimensional measurement point from at least two movement amounts along the ultrasonic transmission / reception direction transmitted / received with different deflection angles. A position tracking unit 113 that obtains the movement amount and adds the two-dimensional or three-dimensional movement amount of the measurement point to the position before the measurement point is moved to track the two-dimensional or three-dimensional movement of the measurement point.
[Selection] Figure 1

Description

  The present invention relates to an ultrasonic diagnostic apparatus that tracks the movement of a subject tissue and an ultrasonic diagnostic apparatus that obtains a tissue property from a tracking waveform.

  The ultrasonic diagnostic apparatus transmits an ultrasonic wave to a subject and receives an ultrasonic wave (reflected echo signal) reflected by the tissue of the subject, and converts the intensity of the received ultrasonic wave into a luminance. A tomographic image of the specimen is obtained. As one form of ultrasonic diagnostic equipment, the motion of the subject tissue is accurately measured by analyzing the phase of the reflected echo signal, and the distortion, elastic modulus and viscosity of the subject tissue are based on the measurement result. Attempts have been made to determine the tissue properties.

  For example, in Patent Document 1, the tissue of a subject is tracked with high accuracy by determining the instantaneous position of the subject using the amplitude and phase of an output signal obtained by detecting a reflected echo signal. A method for capturing minute vibrations superimposed on large-amplitude displacement motion due to pulsation is described.

従って、ΔＴ後の物体Ａの位置ｘ’は次の式（２）で与えられる。

The subject tissue tracking method disclosed in Patent Document 1 will be described with reference to FIG. For the same direction of the subject, the received echo signal of the ultrasonic pulse transmitted at time t = 0 is y (t), and the echo signal of the ultrasonic pulse transmitted at time t = ΔT is y (t + ΔT). To do. In addition, the reception time tx of the echo reflected from the measurement point at a certain position (depth) x is tx = x / (C / 2) [C: propagation in the subject, where t = 0 is the pulse transmission time. The speed of the ultrasound to be given]. Next, if the phase difference between the received echo signals y (tx) and y (tx + ΔT) is Δθ, and the center frequency of the ultrasonic wave near the reception time tx is f, the movement amount Δx of the measurement point within this time ΔT is It is given by equation (1).

Therefore, the position x ′ of the object A after ΔT is given by the following equation (2).

  By repeating this calculation, the position of a specific measurement point in the subject can be tracked. That is, assuming that the reception time of the echo reflected from the position (depth) x ′ is tx ′, the expression (1) is obtained based on the phase difference between the reception echo signals y (tx ′ + ΔT) and y (tx ′ + 2ΔT). And the position x ″ of the measurement point after 2ΔT can be obtained from the equation (2).

  In Patent Document 2, the method of Patent Document 1 is further developed to accurately track the large amplitude displacement motions of the inner and outer surfaces of the blood vessel wall due to the heartbeat, and the motion speed of micro vibrations superimposed on the large amplitude displacement motions. And a method of measuring the strain amount of the blood vessel wall from the difference, obtaining the local elastic modulus from the strain amount and the blood pressure difference, and an apparatus for displaying an image of the spatial distribution of the elastic modulus.

  The elastic modulus calculation method disclosed in Patent Document 2 will be described with reference to FIG. According to this document, the probe 101 irradiates a subject with ultrasonic waves and receives echoes from blood vessels, particularly arteries. Measurement points A and B (two points on the cross section including the central axis of the blood vessel and having different distances in the radial direction from the central axis) are set on the blood vessel wall, and the received signals from the measurement points A and B are patented. Analysis is performed by the method shown in Document 1, and the movement of the measurement points A and B is tracked. Here, the artery repeatedly contracts and dilates due to the heartbeat, and during the systole, the blood vessel itself expands and the thickness of the blood vessel wall decreases rapidly, and during the diastole, the blood vessel itself contracts and slowly The thickness of the vessel wall increases. Therefore, the measurement points A and B exhibit a periodic behavior indicated by the tracking waveforms TA and TB, and a thickness (distance) change waveform W between the measurement points A and B is obtained from the difference between the tracking waveforms TA and TB.

Therefore, assuming that the change amount of the thickness change waveform W is ΔW and the reference thickness at the time of measurement point initialization is Ws, the strain amount ε between the measurement points A and B is given by Expression (3).

そして、以上の計算を断層画像上の複数点に対して行なうことで、弾性率の分布画像が得られる。
特開平１０−５２２６号公報 特開２０００−２２９０７８号公報 Assuming that this strain amount ε is caused by the blood pressure difference ΔP applied to the blood vessel wall, the elastic modulus Er between the measurement points A and B is given by the equation (4).

The elastic modulus distribution image is obtained by performing the above calculation on a plurality of points on the tomographic image.
Japanese Patent Laid-Open No. 10-5226 JP 2000-229078 A

  However, although the subject tissue is accompanied not only by the depth direction but also by the lateral movement, the tissue tracking method described in the above publication can track only the ultrasonic traveling direction, that is, the depth direction movement. There was a problem. Therefore, the present invention is an improvement of the above-described tissue tracking method, and an object thereof is to provide an ultrasonic diagnostic apparatus capable of accurately tracking a two-dimensional movement of a subject tissue. It is another object of the present invention to provide an ultrasonic diagnostic apparatus that can accurately determine tissue properties such as strain, elastic modulus, and viscosity by tracking two-dimensional movement with high accuracy.

In order to achieve this object, an ultrasonic diagnostic apparatus according to the present invention includes:
Means for transmitting and receiving ultrasound with at least two different deflection angles with respect to a measurement point set in the subject;
Means for determining the amount of movement of the measurement point along each ultrasonic transmission / reception direction;
Means for obtaining a two-dimensional or three-dimensional movement amount of the measurement point from at least two movement amounts along the ultrasonic transmission / reception direction transmitted / received with different deflection angles;
A means for tracking the two-dimensional or three-dimensional movement of the measurement point by adding the two-dimensional or three-dimensional movement amount of the measurement point to the position before the measurement point is moved is provided.

Another form of the ultrasonic diagnostic apparatus according to the present invention is as follows:
Means for scanning a cross-section or volume of the subject by each of at least two ultrasound waves provided with different deflection angles;
Means for obtaining a movement amount in the ultrasonic transmission / reception direction of each of a plurality of measurement points set in a two-dimensional or three-dimensional manner in the subject;
Means for obtaining a two-dimensional or three-dimensional movement amount of the measurement point from at least two movement amounts along the ultrasonic transmission / reception direction having different deflection angles for each of the plurality of measurement points;
For each of the plurality of measurement points, means for tracking the two-dimensional or three-dimensional movement by adding the two-dimensional or three-dimensional movement amount to the position before the measurement point is moved is provided.

  These ultrasonic diagnostic apparatuses preferably have means for storing the movement amount of the measurement point along the ultrasonic transmission / reception direction, the two-dimensional or three-dimensional movement amount of the measurement point, or both.

  Further, the means for obtaining the movement amount of the measurement point along the two ultrasonic transmission / reception directions obtains the movement amount of the measurement point for each ultrasonic transmission / reception direction a plurality of times and interpolates the movement amounts obtained for the plurality of times. It is preferable to obtain the amount of movement of the measurement points along the two ultrasonic transmission / reception directions without a time difference.

  Further, the ultrasonic diagnostic apparatus further includes means for calculating a value representing the tissue property of the subject from the result of tracking the detected two-dimensional or three-dimensional movement, and the value representing the tissue property is: It is preferably at least one of the thickness change amount, speed, strain, elastic modulus, and viscosity of the subject tissue.

  Furthermore, after tracking the two-dimensional or three-dimensional movement, it is preferable to track the movement of the measured tissue with ultrasonic waves deflected in a direction parallel to the movement of the measured tissue.

  The ultrasonic diagnostic apparatus according to claim 6, wherein the tracking of the two-dimensional or three-dimensional movement is periodically performed during ultrasonic transmission / reception.

  The tracking of the two-dimensional or three-dimensional movement is preferably performed immediately after the ultrasonic transmission / reception is started after the ultrasonic transmission / reception is stopped.

  According to the present invention, two-dimensional or three-dimensional movement of a subject tissue can be tracked more accurately. Further, by accurately tracking the two-dimensional or three-dimensional movement of the subject tissue, the tissue properties such as strain, elastic modulus, and viscosity of the subject tissue can be obtained with high accuracy.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following explanation, terms ("up", "down", "right", "left" and their derivatives) indicating specific directions and places are used as necessary. It is used to facilitate understanding of the invention and should not be used to interpret the technical scope of the invention.

[Configuration and operation of ultrasonic diagnostic equipment]
FIG. 1 is a block diagram showing a functional configuration of the ultrasonic diagnostic apparatus. As shown in the figure, the ultrasonic diagnostic apparatus includes a control unit 100 as control means. In the drawing, the control unit 100 is displayed in a state independent of other functional units described below, but is associated with these functional units. Although not shown, a user interface (input means) such as a keyboard, a trackball, a switch, and a button is connected to the control unit 100, and necessary information is input to the control unit by operating these user interfaces. . A probe 101 that is used in contact with a subject (not shown but is usually a person) is connected to a transmitter 102 and a receiver 103. When receiving an ultrasonic wave transmission command from the control unit 100, the transmission unit 102 generates a signal for driving the probe 101 at a designated timing and transmits the signal to the probe 101. The probe 101 emits an ultrasonic wave based on the signal output from the transmission unit 102 and irradiates the subject. The probe 101 converts an ultrasonic echo reflected from the inside of the subject into an electric signal.

  Although not shown in the drawing, a plurality of piezoelectric transducers that mutually convert ultrasonic waves and electrical signals are arranged in one or two dimensions in the probe 101, and these piezoelectric transducers are selected and piezoelectric transducers are selected. The timing of applying a voltage to the element is adjusted, and the deflection angle and focus of the ultrasonic wave to be transmitted and received are controlled.

  The receiving unit 103 amplifies the reception signal output from the probe 101 and detects only ultrasonic waves from a predetermined position (focus) or direction (deflection angle).

  The tomographic image processing unit 104 includes a filter, a detector, a logarithmic amplifier, and the like, and mainly analyzes the amplitude of the received signal to image the internal structure of the subject. The imaged image data is transmitted to the image composition unit 106.

  The tissue tracking unit 105 calculates the amount of movement of the subject tissue along the acoustic scanning line from the storage unit 110 that stores the reception signal output from the reception unit 103 and the phase difference between the reception signals based on the above-described Equation 1. The movement amount calculation unit 111, the storage unit 112 that stores the movement amount of the subject tissue calculated by the movement amount calculation unit 111, and the above Equation 2 are expanded and oscillated from the probe 101 with different deflection angles. Position tracking that tracks the two-dimensional or three-dimensional movement of the subject tissue by calculating the amount of movement of the subject tissue and the post-movement position by vector synthesis of the movement amounts in two directions obtained from two ultrasonic waves Part 113. The processing in the tissue tracking unit 105 will be described in detail later.

  From the movement of the subject tissue tracked by the tissue tracking unit 105, the tissue property calculation unit 108 gives a parameter representing the tissue property of the subject tissue, for example, the distortion amount given by the above-described equation 3 or given by the above-described equation 4. Calculate the elastic modulus. The parameter representing the tissue property is converted into numerical data or two-dimensional distribution image data in which the value is converted into color data and developed into two-dimensional coordinates, and transmitted to the image composition unit 106.

  The image synthesizing unit 106 synthesizes numerical data or image data of parameters representing tissue properties such as elastic modulus output from the tissue property calculating unit 108 and the elastic image output from the tomographic image processing unit 104, and the combined image Is output to the image display unit 107 and displayed.

[Processing of organization tracking part]
With reference to FIGS. 2 and 3, the tissue tracking process in the subject will be described.

[Step 1]: The probe 101 operates based on a command from the control unit 100, and the first deflection angle from the upper right to the lower left in FIG. 3 with respect to the measurement point at the position X in the subject. Ultrasound is transmitted to the subject along the acoustic scanning line a deflected with θa, and the reflected echo is received. The received reflected echo is converted into an electric signal (first received signal). The converted electrical signal is stored in the storage unit 110.

[Step 2]: The probe 101 operates again based on a command from the control unit 100, and again transmits ultrasonic waves along the acoustic scanning line a to the subject. The received reflected echo is converted into an electrical signal (second received signal). The converted electrical signal is stored in the storage unit 110.

[Step 3]: The movement amount calculation unit 111 acquires the first and second reception signals from the storage unit 110, and based on the above-described Expression 1 from the phase difference between the two reception signals, the acoustic scanning line a The movement amount (vector amount) ΔX (a) of the position X with respect to the direction along the first direction (first deflection direction) is calculated. The calculated movement amount ΔX (a) is transmitted to the storage unit 112 and the position tracking unit 113.

[Steps 4 and 5]: Based on a command from the control unit 100, the probe 101 performs the second deflection from the upper left to the lower right in FIG. 3 with respect to the measurement point at the position X in the subject. Ultrasonic waves are transmitted to the subject twice along the acoustic scanning line b deflected at the angle θb, and each reflected echo is received. The received reflected echo is converted into an electrical signal (first and second received signals). The converted electrical signals (first and second received signals) are stored in the storage unit 110.

[Step 6]: The movement amount calculation unit 111 acquires the first and second reception signals stored for the acoustic scanning line b, and based on the above-described Expression 1 from the phase difference between these two reception signals. A movement amount (vector amount) ΔX (b) of the position X in the direction along the acoustic scanning line b (second deflection direction) is calculated. The calculated movement amount ΔX (b) is transmitted to the storage unit 112 and the position tracking unit 113.

[Step 7]: Movement amounts ΔX (a) and ΔX (b) are projections (movement components) in the acoustic scanning line a and acoustic scanning line b directions of the true movement amount of the measurement point. Therefore, the position tracking unit 113 calculates the true movement amount ΔX by combining (vector combining) the movement amounts ΔX (a) and ΔX (b) output from the movement amount calculation unit 111 or the storage unit 112.

[Step 8]: Next, the position tracking unit 113 calculates the post-movement position X ′ by adding the movement amount ΔX to the tissue position X before the movement.

  The above steps 1 to 8 are repeated to track the position of the measurement point in the subject. For example, the acoustic scanning line b ′ (acoustics) deflected to the right twice, in the direction along the acoustic scanning line a ′ (acoustic scanning line parallel to the acoustic scanning line a) deflected leftward through the position X ′. The ultrasonic wave is transmitted and received twice in the direction along the scanning line b), the next true movement amount ΔX ′ is obtained, and the movement amount ΔX ′ is added to the position X ′ to obtain the next position X. ”

[Step 9]: The interval between the acoustic scanning lines depends on the arrangement interval of the piezoelectric transducers provided in the probe 101. Therefore, for example, as shown in FIG. 3, the moved position X ′ exists on one acoustic scanning line a ′ or in the vicinity thereof, but does not exist on the other acoustic scanning line b ′ or in the vicinity thereof. In some cases, it may exist between the acoustic scanning lines b and b ′. Therefore, when determining the next acoustic scanning line, the control unit 100 employs the acoustic scanning lines a ′ and b ′ closest to the position X ′ from the calculated position X ′ after movement as the next acoustic scanning lines. To do. Then, the movement amounts Δx ′ (a) and Δx ′ (b) and the movement amount Δx ′ of the position x ′ where the acoustic scanning lines a ′ and b ′ intersect are obtained, and the movement amount Δx ′ is added to the position X ′. Thus, the position X ″ after the movement is obtained.

  Instead of this method, for example, as shown in FIG. 4, when the moved position X ′ is in the middle of the acoustic scanning lines b and b ′, the movement of the position x (a ′, b) on the acoustic scanning line b is performed. The movement amount Δx ′ (a ′, b ′) of the amount Δx ′ (a ′, b ′) and the position x ′ (a ′, b ′) on the acoustic scanning line b ′ is obtained, and these two movement amounts Δx ( An average value of a ′, b) and Δx ′ (a ′, b ′) or a value obtained by linear interpolation may be used as the movement amount ΔX ′ (b) in the direction along the acoustic scanning line b ′.

  In the above description, the ultrasonic wave is first oscillated twice in the direction along the acoustic scanning line a to obtain the movement amount ΔXa, and then the ultrasonic wave is oscillated twice in the direction along the acoustic scanning line b. The amount of movement ΔXb was calculated. First, the ultrasonic waves were oscillated once along the acoustic scanning lines a and b, respectively, and then the ultrasonic waves were oscillated once along the acoustic scanning lines a and b, respectively. Thereafter, the movement amounts ΔXa and ΔXb and the true movement amount ΔX in the direction along the acoustic scanning lines a and b may be calculated.

  Further, the detection times of the movement amounts (for example, ΔXa and ΔXb) along the acoustic scanning line a and the acoustic scanning line b are slightly different. Therefore, in order to reduce the error due to the difference in detection time as much as possible, transmission is performed three times in the direction along the acoustic scanning line a and three times in the direction along the acoustic scanning line b, and each of the two movement amounts. By obtaining (ΔXa1 and ΔXa2, ΔXb1 and ΔXb2) and interpolating these two (for example, linear interpolation), the movement amounts ΔXa and ΔXb at the same time can be obtained. By doing so, it is possible to track the two-dimensional movement with higher accuracy.

[Two-dimensional tracking]
A method for two-dimensionally tracking the positions of measurement points distributed two-dimensionally will be described with reference to FIGS. As shown in FIG. 5, a plurality (a1 to an, b1 to bn) of acoustic scanning lines deflected leftward and rightward in the figure are set, and the inside of the subject is scanned. The scanning order of the acoustic scanning lines may be a1, a2,..., An, b1, b2,..., Bn (n is the number of scanning lines, n = 6 in FIG. 3), or a1, b1, It is good also as a2, b2, ..., an, bn. In this way, all the acoustic scanning lines (a1 to an, b1 to bn) deflected in the left and right directions by one two-dimensional scanning are oscillated once. This one-dimensional two-dimensional scanning is set as “one frame”, and the movement of the measurement points distributed two-dimensionally is traced by repeating this. In FIG. 5, the intersection of the acoustic scanning line a and the acoustic scanning line b is the initial position of the measurement point, and each measurement is indicated by a white circle.

  As an example of tracking of measurement points, tracking of measurement points with an intersection position X of acoustic scanning lines a6 and b2 as an initial position will be described with reference to FIG. A time interval between frames (a transmission / reception interval of ultrasonic waves along the same acoustic scanning line) is assumed to be ΔT. First, from the received signals in the directions along the acoustic scanning line a6 and the acoustic scanning line b2 in the first frame and the second frame, the movement amount ΔX of the position X and the position X after the movement are obtained as described above. Ask for '. Next, the movement amount ΔX ′ and the moved position X ″ are obtained from the received signals in the directions along the acoustic scanning line a4 and the acoustic scanning line b3 in the second and third frames. By repeating, the movement of the measurement point can be tracked, and the two-dimensional movement tracking of the measurement point positions distributed in two dimensions can be performed by performing the same operation for all the measurement points. In order to eliminate the error caused by the deviation, the ultrasonic wave is transmitted and received three times in each deflection direction as described above, and the two movement amounts acquired in each direction are interpolated (for example, linear interpolation). It is preferable to obtain the movement amount at the same time.

  FIG. 7 shows an example of two-dimensional tracking of the movement of a plurality of measurement points. Black circles are measurement points, and corner measurement points are indicated by white circles. 7A shows the initial position of the measurement point, FIG. 7B shows the distribution of the measurement point position after ΔT obtained from the received signals of the first frame and the second frame, and FIG. 7C shows the second frame. This is a distribution of measurement point positions after 2ΔT obtained from the received signal of the third frame. It can be seen that it is possible to accurately track the movement in the compression direction in the upper right and lower left direction and the expansion direction in the upper left and lower right direction.

[3D tracking]
According to the present invention, the movement of the tissue in the subject can also be tracked three-dimensionally. In the three-dimensional tracking, as shown in FIG. 8, a two-dimensional array probe 121 in which the piezoelectric transducers 120 are arranged two-dimensionally is used, and the measurement point (position X) is not in the same plane. Ultrasonic waves are transmitted and received in the direction along the acoustic scanning lines a, b, and c, and the movement amounts (vector quantities) ΔXa, ΔXb, and ΔXc in the direction along the acoustic scanning lines are obtained from the obtained three received signals. Then, these three movement amounts are combined (vector combination) to obtain a true three-dimensional movement amount ΔX, and this three-dimensional movement amount ΔX is added to the initial position X to obtain a new position X ′. By repeating this process, the measurement point position can be tracked three-dimensionally.

  FIG. 9 shows an example in which the three-dimensional tracking described with reference to FIG. 8 is extended. In the figure, an arrow line is an acoustic scanning line, and a dotted line is a volume (volume region) scanned by one frame of acoustic scanning. First, as shown in FIG. 9A, a volume (area indicated by a dotted line) is scanned from the two-dimensional array probe 121 using a non-deflection ultrasonic wave group. Next, as shown in FIG. 9B, the volume is scanned using an ultrasonic wave group deflected from the upper right to the lower left in the figure. Next, as shown in FIG. 9C, the volume is scanned using an ultrasonic wave group deflected from the upper left to the lower right in the figure. Using the data (reception signal) obtained from these three scans, the movement amount in three directions is obtained for all measurement points by the method described with reference to FIG. The true three-dimensional movement amount of the measurement point is obtained, and this three-dimensional movement amount is added to the initial position of each measurement point to obtain new positions of all measurement points.

  The three-dimensional movement tracking is particularly useful for the diagnosis of the heart, and the heart function can be quantitatively diagnosed by accurately measuring the movement of the heart that moves three-dimensionally. Since the sound speed in the subject tissue is finite, there is a problem that when all the volumes are scanned, the repetition frequency of the ultrasonic wave at each measurement point decreases. This can be solved by narrowing the measurement area or performing a parallel reception technique used conventionally.

[Diagnosis of blood vessel wall]
The case where this method is applied to the diagnosis of the blood vessel wall will be described with reference to FIGS. As shown in FIG. 10 (b), the actual blood vessel wall is pulled by the movement of the heart or accompanied by the movement of the blood vessel in the axial direction due to friction caused by blood flow. To be precise, it moves similar to an ellipse having a major axis with a double-headed arrow in the figure. Especially in the carotid artery, such an elliptical movement is remarkable. However, the blood vessel wall diagnosis disclosed in Patent Document 1 assumes that the blood vessel wall operates only in the radial direction due to blood pressure fluctuation due to heartbeat, as shown in FIG. There is a problem that it is impossible to accurately grasp the movement of the.

  Therefore, in the present invention, as shown in FIG. 10 (c), first, ultrasonic waves are transmitted and received in directions along two acoustic scanning lines having predetermined deflection angles, and the received signals are used to perform two-dimensional analysis of the subject tissue. The movement of the blood vessel and surrounding tissue is detected. Next, as shown in FIG. 10 (d), ultrasonic waves are transmitted and received in a direction along one kind of acoustic scanning line deflected so as to be parallel to the moving direction of the blood vessel wall, and the received signal of the subject tissue is received. Tracking is performed, thereby obtaining tissue property parameters such as strain, elastic modulus, viscosity, moving speed, and thickness of the blood vessel wall.

  For example, when the acoustic scanning in FIG. 10C is performed, there are 16 acoustic scanning lines per frame. Further, when the acoustic scanning of FIG. 10D is performed, there are eight acoustic scanning lines per frame. Therefore, as described above, first, as shown in FIG. 10C, ultrasonic waves are transmitted and received along acoustic scanning lines having two kinds of deflection angles to determine the moving direction of the blood vessel wall. By scanning the acoustic scanning line along the line, the time interval ΔT between the frames can be halved, and thus it is possible to deal with a fast-moving subject.

  Specifically, immediately after shifting from the ultrasonic transmission / reception stop state to the ultrasonic transmission / reception state, the ultrasonic scanning shown in FIG. 10C is performed for several heartbeats to obtain a two-dimensional movement, and then the blood vessel wall The tissue property parameter is obtained by performing the scanning shown in FIG. It is preferable that the scanning shown in FIG. 10C is performed periodically thereafter, every predetermined time, or every predetermined heart rate. By doing so, it is possible to accurately track the movement of the blood vessel wall, and to obtain a highly accurate tissue property parameter of the blood vessel wall.

  FIG. 11 is a monitor screen displaying an example of the result of measuring the elastic modulus of the blood vessel wall using the ultrasonic diagnostic apparatus. In the figure, an elastic modulus image 201 representing the distribution of elastic modulus of the part is displayed in color on the monitor in a superimposed manner on the monochrome tomographic image 200 of the blood vessel wall. The elastic modulus image is obtained with an accurate elastic modulus by the method shown in FIG. 10, and a color corresponding to the elastic modulus is given. As described above, according to the present invention, since the elastic modulus of the blood vessel wall can be displayed, an accurate diagnosis can be made.

  In FIG. 1, a plurality of functions necessary for implementing the present invention are shown as independent blocks. However, the present invention is not limited to this. For example, the control unit 100, the tomographic image processing unit 104, the tissue tracking unit 105, and the image synthesis unit 106 are used. The tissue property calculation unit 108 and the like can be realized as software on the CPU.

  As described above, according to the present invention, it is possible to more accurately track the two-dimensional movement of the subject tissue, and using this, the strain, elastic modulus, viscosity, and vessel wall thickness of the subject tissue can be used. It has an effect that tissue properties such as moving speed can be obtained with high accuracy, and is useful as an ultrasonic diagnostic apparatus for measuring tissue properties of a subject tissue.

1 is a functional block diagram of an ultrasonic diagnostic apparatus according to the present invention. The flowchart which shows the tissue tracking process of an ultrasonic diagnosing device. Explanatory drawing of two-dimensional position tracking by an ultrasonic diagnostic apparatus. Explanatory drawing of two-dimensional position tracking by an ultrasonic diagnostic apparatus. Explanatory drawing of an acoustic scanning line and a measurement position. Explanatory drawing of two-dimensional position tracking of the measurement position distributed two-dimensionally. The figure which shows an example of the two-dimensional position tracking result of the measurement position distributed two-dimensionally. Explanatory drawing of the three-dimensional position tracking by the ultrasonic diagnosing device which concerns on this invention. Explanatory drawing of the scanning method of the three-dimensional position tracking by an ultrasonic diagnosing device. Explanatory drawing of the scanning method in the moving direction of a blood-vessel wall and an ultrasonic diagnosing device. The figure which shows an example of the measurement result of a blood vessel wall. Explanatory drawing of basic operation for performing tissue tracking from phase difference. The basic operation explanatory drawing which calculates | requires distortion amount from a tissue tracking waveform.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100: Control part, 101: Probe, 102: Transmission part, 103: Reception part, 104: Tomographic image processing part, 105: Tissue tracking part, 106: Image composition part, 107: Monitor, 108: Tissue property calculation part 110: storage unit, 111: movement amount calculation unit, 112: storage unit, 113: position tracking unit, 200: tomographic image, 201: elastic modulus image.

Claims (8)

Means for transmitting and receiving ultrasound with at least two different deflection angles with respect to a measurement point set in the subject;
Means for determining the amount of movement of the measurement point along each ultrasonic transmission / reception direction;
Means for obtaining a two-dimensional or three-dimensional movement amount of the measurement point from at least two movement amounts along the ultrasonic transmission / reception direction transmitted / received with different deflection angles;
An ultrasonic diagnosis comprising means for tracking the two-dimensional or three-dimensional movement of the measurement point by adding the two-dimensional or three-dimensional movement amount of the measurement point to the position before the measurement point is moved. apparatus. Means for scanning a cross-section or volume of the subject by each of at least two ultrasound waves provided with different deflection angles;
Means for obtaining a movement amount in the ultrasonic transmission / reception direction of each of a plurality of measurement points set in a two-dimensional or three-dimensional manner in the subject;
Means for obtaining a two-dimensional or three-dimensional movement amount of the measurement point from at least two movement amounts along the ultrasonic transmission / reception direction having different deflection angles for each of the plurality of measurement points;
Ultrasonic waves characterized by comprising means for tracking the two-dimensional or three-dimensional movement of each of the plurality of measurement points by adding the two-dimensional or three-dimensional movement amount to the position before the measurement point is moved. Diagnostic device.   The apparatus according to claim 1 or 2, further comprising means for storing a movement amount of the measurement point along the ultrasonic transmission / reception direction, a two-dimensional or three-dimensional movement amount of the measurement point, or both. The ultrasonic diagnostic apparatus as described.   The means for obtaining the movement amount of the measurement point along the two ultrasonic transmission / reception directions obtains the movement amount of the measurement point for each ultrasonic transmission / reception direction a plurality of times and interpolates the movement amount obtained for the plurality of times, The ultrasonic diagnostic apparatus according to claim 1, wherein the movement amount of the measurement point along two ultrasonic transmission / reception directions is obtained without a time difference.   The apparatus further includes means for calculating a value representing the tissue property of the subject from the result of tracking the detected two-dimensional or three-dimensional movement, and the value representing the tissue property is at least a thickness change amount of the subject tissue. The ultrasonic diagnostic apparatus according to claim 1, wherein the ultrasonic diagnostic apparatus is any one of a velocity, a strain, an elastic modulus, and a viscosity.   6. After tracking the two-dimensional or three-dimensional movement, the movement of the measured tissue is tracked with an ultrasonic wave deflected in a direction parallel to the movement of the measured tissue. An ultrasonic diagnostic apparatus according to claim 1.   The ultrasonic diagnostic apparatus according to claim 6, wherein the tracking of the two-dimensional or three-dimensional movement is periodically performed during ultrasonic transmission / reception. 8. The ultrasonic diagnostic apparatus according to claim 6, wherein the tracking of the two-dimensional or three-dimensional movement is performed immediately after the ultrasonic transmission / reception is started after the ultrasonic transmission / reception is stopped.

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