JPS6373937A - Ultrasonic diagnostic apparatus - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to an ultrasonic diagnostic apparatus that diagnoses tissue within a subject using ultrasound, and particularly relates to an ultrasonic diagnostic apparatus that diagnoses tissues within a subject using ultrasound, and particularly The present invention relates to an ultrasonic diagnostic apparatus that characterizes tissue by measuring tissue characterization information such as sound wave propagation velocity, and is equipped with functions for measuring scattered waveforms, sound velocity, etc., and displaying the same for diagnosis.

(Prior Art) For example, the scattering waveform and ultrasonic propagation velocity (hereinafter simply referred to as sound velocity) in a specimen are influenced to a large extent by the composition present in the ultrasound propagation path in the specimen. In other words, this means that it is possible to detect lesions such as tumors in organs, liver cirrhosis, etc. in a living body based on the scattering waveform and sound velocity. Measuring the speed of sound has great clinical value.

Therefore, attempts have been made to utilize this fact to obtain information such as the scattering waveform and sound speed in the living body, and to use this information to examine the composition at a target location.

Conventionally, as a practical ultrasonic measurement method for such examinations, a method as shown in FIG. 8 using an electronic scanning type ultrasonic diagnostic apparatus has been proposed.

That is, in the figure, 1 is a probe for ultrasonic linear electronic scanning, and this probe 1 is used to enter the body from one end A of the ultrasonic transmitting/receiving surface 2 that is in contact with the body surface (not shown).
Fires ultrasonic pulses in the direction.

Here, an electronic scanning type ultrasonic diagnostic device is an ultrasonic diagnostic device that uses ultrasonic waves (a probe with a radial array) in which multiple sets of ultrasonic transducers (hereinafter simply referred to as transducers) are arranged in parallel. Several adjacent transducers in the probe are grouped together, and a drive pulse is applied to each of the group of transducers with a predetermined delay time determined according to the direction of the transmitted ultrasound beam and the position of the transducer in the beam. The ultrasonic waves from each excited transducer propagate radially and interfere with each other, canceling each other out in some areas and reinforcing each other in others. This is a method to obtain an ultrasonic beam as a result.The wave is generally received by the above group of transducers used for wave transmission, and the detection signal of this (Tatsukinko) is delayed by the delay time at the time of wave transmission. After aligning the time axes, they are combined to form a received signal.Then, by shifting the group of transducers one pitch at a time, the position of the generated ultrasonic beam shifts, so the excited imaging By electrically selecting the mover and controlling the excitation timing, linear scans can be performed, and sector scans can also be performed at desired positions.

In this way, if the beam-shaped ultrasonic pulse generated in the θ direction is set at a position in the liver tissue, it will travel straight along the transmission path 4 in the liver tissue and go straight to the point P.
reflect.

Here, among these reflected waves (echoes), we do not refer to the transducer group that transmitted the echo that arrived at the probe 1 following the receiving path 5, but to the transducer group at the incident position of the echo that arrived (this It is received by the transducer group at the right end B of the probe 1.

Such a method in which the transmitting path and the receiving path of the ultrasonic beam intersect is called a cross beam method. The waveform shape of the reflected wave obtained by this includes various information about living tissue, and in particular, the size of the scattered waveform, such as the width of the peak value, the integral value of the waveform indicating its energy, etc. It reflects the tissue scattering coefficient, density, and spatial state of multiple tissue elements.

Also, since the distance y between A and B is known, the route 4,
If the propagation time t of the ultrasonic wave propagating through the liver tissue is measured, the sound velocity C in the liver tissue can be determined by c=y/(t-Sinθ) (1).

This principle is used to measure the scattered waveform and sound speed.

Standardly, the sound speed in living tissue is Co = 1530 [m/s]
Then, in order to radiate the ultrasound beam in 60 directions, the delay time between adjacent elements τ0τo = (d/Co) ・s
inθo −(2), and each element is set to be driven with such a delay time difference.

If the sound velocity in the living tissue is Co, the ultrasonic beam will travel in the θ0 direction, but it is generally not limited to Co and has a different value C. The propagation direction θ of the ultrasonic wave at this time is sinθ/C=sinθo/Co from Snell's law.
...The value shown in (3) is obtained.

The peak value of the waveform indicates the reflected wave from point P, and the propagation time t can be found by detecting the time (address) of the peak value with the waveform analysis circuit. Substituting the above equation (3) into equation (1), the speed of sound C in the living body is C=V o ・s+n o ・
・A4)). Further, by substituting the equation (2) into the equation (4), C=y··τ0 (4°) is obtained. Since ¥, d, and τ0 are known, the calculation circuit calculates the above (4°) using the propagation time t obtained by measurement.
Calculate the formula to find the value of the sound speed C, and output it to the display.

FIG. 9 is a time chart showing a measurement method mainly based on propagation time, in which an ultrasonic pulse is emitted at a time slightly delayed from the falling edge to of the rate pulse in (a). The pulse peak time is tl.

In this way, when there is a point reflector P at the intersection of the center of the transmitting beam and the receiving direction, the time t
The reflected wave having a peak at 2 is 1q, and t is determined as the time interval between t2 and tl. The blood vessels in the liver are well maintained.
It is possible to adjust the probe so that it is at the point, but since the target is a living body, it is actually rare for something equivalent to a point reflector to exist at the intersection of the beams.

If the observation site is a liver, for example, it is assumed that the vicinity indicated by point P is a relatively uniform liver tissue. Therefore, the counter-wave from the vicinity of point P becomes a relatively uniform reflected wave from the liver tissue. As shown in Fig. 10, the beam has a certain thickness centered around point P and spread to points Pi and P2 on both sides, so the earliest of these reflected waves reaches via point 11 in Fig. 10. The one that arrives the latest is the one that passes through 22 points. Therefore, the received waveform spans a period of time corresponding to the width from Pl to P2.

Therefore, the received waveform in this case becomes a so-called scattered waveform that spreads out as shown in Figure 9(b).Moreover, the tissue is not completely uniform, and since it is a living tissue, it is scattered by various scatterers. Since the scattered ultrasound waves are received including speckle signals, which are signal components that interfere with each other, various random irregularities occur in the waveform.

Therefore, since it is not possible to detect the peak value of the waveform with this method, by slightly moving the transmitting and receiving center position, we obtain echo data with the beam intersection position in the liver slightly shifted, and add these together to eliminate the noise. Try to cancel out the ingredients. In other words, since the unevenness of the waveform in FIG. 9(b) is considered to be random, the waveform becomes considerably smoother if the beam intersection is changed and the beams are added several hundred or even times, or by peak hold processing. The result is as shown in FIG. 9(C).

Alternatively, instead of the above method, curve fitting may be performed by the least squares method using a unimodal function having one peak. It can be replaced with .

Next, the calculation circuit calculates t=t2-t as shown in FIG. 9(d).
A cross-mode sound velocity measurement method has been proposed in which the propagation time t can be determined as l.

This method is called the 4-beam method, and specifically, as shown in Figure 2, the reflection point at the upper boundary, the measurement point) Pl
l and Pl2, the foul point at the lower boundary (measurement point > In measuring the local sound speed of the abnormal part included in Poo, the ultrasonic beam transmission and reception path is (1) A→Poo-+B, (2)
A-+Pn →C, (3) B-+Poo →A.

(4) Four routes are taken: B-+P 12 → D. In other words, each of the A and B positions of the probe 1 is used as an ultrasonic beam transmitting position and also as a receiving position. Wave is transmitted from position A, reflected by Poo is received at position B, then transmitted from position A, and Pn
The wave reflected at Poo is received at position C, then transmitted from position B, the wave reflected at Poo is received at position A, then transmitted from position B, and the wave reflected at Pl2 is transmitted at position D. By switching between transmitting and receiving, the measurement path is made symmetrical, and the directional directions of the ultrasonic beams in the transmitting and receiving directions are set at the same angle θ.

According to this, detection measurements are performed at least twice per route, on the outbound and return trips, resulting in symmetrical measurements, and the average ultrasonic propagation velocity is determined based on the information obtained from these detection measurements, so statistical analysis is performed. This results in a uniform average, which makes it possible to reduce errors.

Such a Talos mode sound velocity measurement function is incorporated into an ultrasonic diagnostic apparatus, and is usually displayed on a display together with an ultrasonic image (for example, a B-mode image).

By the way, the reflected waves (scattered waveforms) obtained by such a loss beam method include not only echoes from the target parenchyma such as the liver at point P, but also echoes from non-target parts such as non-uniform media such as the abdominal wall and diaphragm in the living body. Includes echoes from . Therefore, the waveform of the reflected wave obtained is the 11th
Figure (a).

As shown in (b) and (c), the true echo signal a is mixed with an echo signal that becomes an artifact. Therefore, such reflected waves cannot be trusted because they contain inaccurate information, and cannot be used as data for determining the presence or absence of a disease. Therefore, accurate diagnosis becomes impossible.

(Problems to be Solved by the Invention) As described above, in conventional ultrasonic diagnostic equipment, the reflected waves obtained by the cross beam method contain artifacts, so accurate diagnosis cannot be made. There is.

The present invention has been made in response to the above-mentioned problems.
It is an object of the present invention to provide an ultrasonic diagnostic apparatus that removes artifacts if the reflected waves contain them.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention compares the reflected waves obtained from the target site with a plurality of waveform selection criteria set in advance, and selects all The present invention is characterized in that it includes a waveform selection means that outputs the waveform only when the waveform selection criteria are satisfied.

(Function) A plurality of waveform selection criteria are set in advance, and the obtained reflected wave is compared with all of these waveform selection criteria. Only when all the waveform selection criteria are satisfied as a result of comparison, this reflected wave is output and used as data for determining the presence or absence of a disease. If even one waveform selection criterion is not satisfied, this foul wave is not output and is removed. Therefore, since the influence of artifacts can be avoided, accurate diagnosis can be performed.

(Embodiment) FIG. 1 is a block diagram showing an ultrasonic diagnostic apparatus according to an embodiment of the present invention. Reference numeral 1 denotes an ultrasonic probe, in which, for example, 128 elements (radial elements T1 to T128) are connected in a linear manner to transmit and receive ultrasonic waves. The probe 1 is constituted by 82 lines.

12 is a lead wire; 13 is a multiplexer which is a circuit selection switch; 15 is a transmission delay circuit for obtaining the amount of delay to be given to each of a group of vibrators to be excited;
14 is a pulser that generates pulses for ultrasonic excitation driving;
6 is a reception delay circuit for obtaining the echo delay amount necessary for aligning the time axis etc. according to the reception direction and element position for each of the radial elements used for reception; A display used for displaying character information, etc., 18△ is a calculation circuit, 19 is a receiving i-extension circuit 16, and synthesizes, amplifies and detects received echo signals from 1q transducers T1 to T128, Also, a receiving circuit performs logarithmic conversion and corrects the signal level according to depth and outputs it as a received signal, 20 is an A/D converter that converts the received signal into a digital signal, and 21 is a pulse generator for pulser drive pulse generator 1. An oscillator that generates a clock signal for sequentially updating addresses in the memory in order to sample and store signals and echoes from the target part of the subject; 22 is a memory for storing received signals; 23 is an oscillator for each generation of an ultrasonic pulse; A processing circuit 24 adds the stored data value stored at the same address in the memory 22 and new input data, averages it, and stores the added average value at the corresponding address; Examine the data indicating the peak value using the sample values of the averaged received waveform, use this to find the time (address) of the data with the peak value, and also calculate the size of the scattered waveform, such as the peak amplitude value 1 width and its energy. This is a waveform selection circuit that obtains waveform characteristics such as a waveform integral value indicating .This waveform analysis circuit 24 also performs a waveform selection operation that compares a scattered waveform, which is a reflected wave, with a preset waveform selection criterion, as will be described later. The calculation circuit 1B calculates the propagation time t from the time information obtained by the waveform analysis circuit 24, and also calculates the waveform characteristic matrix of the scattered waveform in the internal tissue of the subject based on the obtained propagation time t. It has the ability to calculate the speed of sound, spatially average it, and output it.

This calculation result is then displayed on the display 17. 25.DELTA. is a system control means, which is centered around a CPU (Central Processing Unit; for example, a microprocessor) and controls the entire system. Reference numeral 26 denotes a changeover switch, which selects and switches the supply route for the combined output of the reception delay circuit 16 to the cross-mode measurement side X and the ultrasonic B-mode image 17 to the ultrasonic device side B. 27 is a receiving circuit on the ultrasonic device side, which performs amplification, detection, logarithmic conversion, etc. of the received signal. 28 is an A/D converter, which converts the output of the receiving circuit 27 into a digital signal. Two are marker generators, which generate image data for displaying the measurement route (beam path route) of the cross-mode measurement. 30 is a digital scan converter, which has a frame memory and sequentially updates and stores the digital data output from the A/D converter 28 at an address corresponding to the beam position where the data is collected. At the same time, reading is performed in accordance with the scanning timing of the display 17, so that the difference between the acquisition timing of the ultrasonic image and the display timing on the display 17 is converted without any problem by interposing the frame memory. . Further, the output of the marker generator 29 is applied to a position corresponding to the measurement route of the cross-mode measurement of the B-mode image on the frame memory of the digital scan converter 30.

The memory 22 also updates and stores the data of the A-mode image. Furthermore, although not shown, the display 17 has a video RAM serving as a display image memory, and displays the waveform features, sound speed data, and A-mode image calculated by the calculation circuit 18.

It is controlled by the control means 25A to store graphs of waveform features, change patterns of sound speed values, etc. in a predetermined layout and in a predetermined format. And this video RAM
Above image data and digital scan converter 3
Display the image based on the output of 0.

Reference numeral 31 denotes a cross-mode measurement area setting device for setting a parallel movement area of a beam intersection in a beam path for cross-mode measurement and a measurement start position. The system control means 25A performs system control such that the beam path for cross-mode measurement is moved in parallel from the measurement start position according to the setting of the cross-mode measurement area 32. Also,
The system control means 25Δ controls the operation of the multiplexer 13, sets the delay times of the transmission delay circuit 15 and reception delay circuit 16, controls the operation of the calculation circuit 18, and controls the changeover switch 26 according to a predetermined program. It controls switching control, marker output control of the marker generator 29, etc.

While ultrasonic scanning is normally performed for B-mode, it is controlled to transmit and receive ultrasonic waves for cross-mode measurement in between (every predetermined timing), and the real-time display of B-mode and the waveform characteristics d and calculation of sound velocity values and display of the results, and calculation of average sound velocity of all beam paths and plot display thereof.

Regarding cross mode measurement, for example, the operation of the multiplexer 13 is controlled as follows.

That is, as shown in Fig. 2, this device measures the local sound speed of the different B part included in the reflection points (measurement points) Pll and PI3 at the upper boundary and the reflection point (measurement point) Poo at the lower boundary. , the ultrasonic beam transmission and reception path is A-)PO
CI-B, A→Po →C, B-Poo-+A, B-+
Try to take four routes: P+2-+D. That is, each of the A and B positions of the probe 1 is used as an ultrasonic beam transmitting position and also as a receiving position. Then, the wave is transmitted from position A, reflected at Poo, and received at position B, then transmitted from position A, and the wave reflected by Pll is received at position C1 (received at U, then transmitted from position 8). Wave, Poo
By switching the transmission and reception, such as receiving the wave at position A, then transmitting it from position B, and receiving the wave reflected at P+2 at position D, the measurement path can be symmetrical. Furthermore, the directivity directions of the ultrasonic beams in the transmission and reception directions are set at the same angle θ. Furthermore, by making the measurement route symmetrical, it is possible to prevent statistically uneven averages, thereby reducing errors.

The operation of the device having such a configuration will be explained.

In this device, cross-mode sound velocity measurement is performed using four routes 81. as shown in FIG. B2. Measurement shall be made using B3,84. Then, the changeover switch 26 is temporarily switched from the terminal B side to the X side at a predetermined timing between the ultrasonic electronic scans in the B mode, and waveform characteristics and sound velocity measurements are performed.

To explain specifically, first, the system control means 2
5A, the changeover switch 26 is switched to the terminal B side, and the multiplexer 13 is selected for linear electronic scanning, and the delay circuits 15, 1
6, the delay time for linear electronic scanning is set;
With these delay times, ultrasonic waves are transmitted and received from the transducer group selected by the multiplexer 13. The combined output of this received signal is amplified and detected by the receiving circuit 27, and the A/
The data is converted into digital data by the D converter 28 and input to the digital scan converter 30. The data is then stored in the frame memory location of the digital scan converter 30 corresponding to the ultrasound scan position. Such ultrasonic scans are sequentially performed while sequentially shifting the scan position, and an ultrasonic B-mode image is formed in the digital scan converter 30. Furthermore, the marker generator 29 outputs a marker for the cross-mode measurement beam path, and the marker is stored in the frame memory of the digital scan converter 30 at a position corresponding to the cross-mode measurement position. . The digital image created in this way
The image data on the frame memory of the scan converter 30 is read out in accordance with the scanning of the display 17, and is provided to the display 17 for display.

At a predetermined timing, the system uII means 25A
switches the selector switch 26 to the terminal X side.

Then enter cross mode measurement. This measurement is first performed on the route B1 at the starting point position set by the setting device 31, and the waveform feature amount and sound speed are measured.

That is, the delay time of the transmission/reception delay circuit 15 is set under the control of the system control means 25A. This delay time is the delay time difference τ between each adjacent radial element.
0 is set so that the relationship is τo-(d/Co)sinθ0. Then, by the switching operation of the multiplexer 13, the transducers uT1 to T32 bent at the point A of the probe 1 are connected to the output end of the pulser 14.

Further, a rate pulse is generated by the clock oscillator 21 and is input to the pulser 14 via the transmission delay circuit 15. Then, from the pulser 14, the corresponding transmission delay circuit 1
The excitation pulse is outputted at a timing shifted by a delay time of 5, and is input to the corresponding transducer of the pulser among the transducers T1 to T32, and the transducer generates an ultrasonic wave. Then, the ultrasonic beam is transmitted in a predetermined direction θ determined by the delay time.

On the other hand, under the control of the system control means 25A, the delay time of the transmission delay circuit 16 is set, and the multiplexer 13
By the switching operation, the transducer groups T97 to T128 belonging to point B of the probe 1 are connected to the input terminal of the reception delay circuit 16.

As a result, the ultrasonic beam transmitted from the transducer group belonging to point A of probe 1 toward the subject is reflected at point Poo and is received by the transducer group belonging to point B of probe 1. The echoes are given the same time difference as in the case of transmission by the reception delay circuit 16, and then combined and output.

The reception echo synthesis output from this reception delay circuit 16 is
After being amplified and detected by the receiving circuit 19, it is converted into a digital value by the A/D converter 2Q, and is read into the memory 22. In the memory 22, the address is updated at a predetermined timing every time an ultrasound beam is transmitted by the clock signal output from the clock oscillator 20, and writing is controlled by the system control means 25A.
Echoes from measurement points are stored in a form that corresponds to time. This becomes A-mode image data.

When the above-mentioned ultrasonic transmission and reception is performed a plurality of times from the transducer group bent at each of the points A and B of the probe 1, the processing circuit 23 functions to average the received echoes.

When this work is completed, the system control means 25A switches the selector switch 26 to the terminal B side again, and starts collecting B-mode images. Then, at a predetermined timing, the system control means 2
5A, the selector switch 26 is switched to the terminal X side, and the process moves to cross mode measurement with the route B2 open.

Then, the multiplexer 13 operates under the control of the system control means 25A, and this time, instead of the transducer group belonging to point B, the transducer group belonging to the 0 point of the probe 1 is connected to the input terminal of the receiving delay circuit 16. The reflected component at point Pat of the ultrasonic wave transmitted by the transducer group bent at the point A of the probe 1 is received by the transducer group bent at the zero point of the probe 1.

The reception echoes are given the same time difference as in the case of transmission by the reception delay circuit 16, and then synthesized and output.

The combined output of the received echoes is amplified and detected by the receiving circuit 19 in the same way as in the case described above, and is then used to measure the time t2 from transmitting the ultrasonic wave to receiving the wave on the route B2.

When this work is completed, the system control means 25A switches the selector switch 26 to the terminal B side again, and starts collecting B-mode images. Then, at a predetermined timing, the system tl control means 25A moves to the cross mode measurement in which the changeover switch 26 is opened to the terminal X side to the route 83.

Then, the multiplexer 13 is operated under the control of the system control means 25A, and the transducer groups T97 to T belonging to the B point of the probe 1 are changed from the transducer group that bends to the A point this time.
128 and the output end of the pulser 14 are connected, and the transducer group belonging to the point A of the probe 1 is connected to the receiving delay circuit 16 instead of the transducer group belonging to the zero point. Then, an ultrasonic wave is transmitted from the transducer group belonging to point B of probe 1, and the reflected component of the transmitted ultrasonic wave at point Poo is received by the transducer group that bends to point A of probe 1. Ru. The reception echoes are given the same time difference as in the case of transmission by the reception delay circuit 16, and then synthesized and output.

The combined output of the received echoes is amplified and detected by the receiving circuit 19 in the same manner as in the above case (E), and then is used to measure the time t3 until receiving the ultrasonic waves from the ultrasonic wave transmitted on the route B3. .

When this operation is completed, the system control means 25A switches the selector switch 26 to the terminal B side again, and starts collecting B-mode images. Then, at a predetermined timing, the system control means 2
5A switches the selector switch 26 to the terminal X side and moves to the route B4 for cross mode measurement.

The multiplexer 1 is controlled by the system control means 25A.
3 operates, and this time, instead of the transducer group belonging to point A, the transducer group belonging to point D of probe 1 and the receiving delay circuit 16 are activated.
is connected to the input terminal of

Then, when an ultrasonic wave belonging to point B of probe 1 is transmitted (when an ultrasonic wave is transmitted from the transducer), the reflected component of the transmitted ultrasonic wave at point PI2 is reflected by the transducer group belonging to point D of probe 1. The received echoes are given the same time difference as in the case of transmission by the receiving delay circuit 16, and then synthesized and output.

The combined output of the received echoes is amplified and detected by the receiving circuit 19 in the same way as in the case described above, and then used to measure the time t4 from transmitting the ultrasonic wave to receiving the wave on the route B4.

When this work is completed, the system control means 25A switches the selector switch 26 to the terminal B side again, and starts collecting B-mode images. Then, at a predetermined timing, the system control means 2
5A, the selector switch 26 is switched to the terminal X side, and the process moves to the cross mode measurement in which the route of B1 is opened. This operation is repeated until the measurement route is shifted to the set area.
The waveform characteristic matrix and the incremental average value of the echo signals in all of the shifted areas in the four routes B1 to B4 are obtained, and the real-time B-mode image is displayed and the data for cross-mode measurement is averaged.

In this way, the data that has been averaged a predetermined number of times and stored is read out from the memory 22, and the waveform analysis circuit 24 examines the data indicating the waveform characteristics and its peak, and the address where the data is stored is checked. The information is sent to calculation circuit 18 as time information. Based on this, the calculation circuit 18 calculates 81.82. B3. Time t1 from transmission of ultrasound to the above peak for each route of B4. t
2, t3. t4 is calculated. After that, each rule
-Another sound velocity value V1. V2. V3. V4 and the average sound velocity value V over the entire beam path are calculated and displayed on the display 17.

Figures 3 (a) and (b) show the scattering waveforms obtained by the loss mode measurement method, and the vertical axis is the amplitude A.
, the horizontal axis is time t. The peak value of each scattering waveform is A
When P, a3 in Figure 3(a) is from Ap to Xd.
The waveform width W at the position At, which is reduced by 3 dB, for example, is determined. In addition, in FIG. 3(b), the area value S of a region 1 surrounded by A, p and W is determined. These peaks [
Ap, waveform width W2, area value S, etc. indicate waveform characteristics of the scattered waveform.

Therefore, in the normal mode, the B mode image and the waveform feature matrix W
Only l, W2, Wa, Wa (average value of the waveform width measured for each route), the measured sound speed value, and the average sound speed time change diagram are updated and displayed in sequence.

FIGS. 4(a) to 4(C) explain the principle of the waveform selection operation of the scattered waveform obtained by the loss mode measurement method, and a plurality of waveform selection criteria are provided. These waveform selection operations are performed by the waveform analysis circuit 24 and calculation circuit 18.
carried out by

A plurality of waveform selection criteria will be sequentially explained below.

(1) The first reference principle is to determine whether or not the value At, which is an X dB reduction from the peak value Ap, intersects on both sides as shown in FIG. 4(a). If the lines intersect only on one side (intersection C1) as shown in the figure, this standard will be violated. Therefore, all the data of the repetition number N=No are removed.

(2) The second standard principle is that, as shown in Fig. 4(b), the value A1, which is XdB down from the peak value Ap, crosses on both sides (
The purpose of this is to compare the waveform width W× with a preset waveform width WHAX to determine the magnitude of the waveform width W× at the intersection C1, C2). If W×>WFIAX, it will deviate from this standard.

(3) The third reference principle is to determine whether the value At, which is XdB down from the peak value Ap, is at or near the O level, as shown in FIG. 4(a).

This makes it possible to remove echo signals that are susceptible to minute-level artifacts.

(4) The fourth standard principle is to determine whether or not the sound velocity value Vx that is included in the peak value Ap is included between the preset value V1iAX and VHTN.From experience, VHAX
= 1700m/S, VHIN = 1350m
If it is set to about /s, if it is not included in these ranges, it can be considered as an abnormal case (artifact has been introduced), and this criterion will be violated.

Then, the reflected wave is compared with all of the selection criteria (1) to (4) above using AND logic. As a result, if any one of the four selection criteria is not satisfied, this reflected wave is not output and is removed.

Only reflected waves that satisfy all selection criteria of the /I type are output. Therefore, in the case of reflected waves including artifacts as shown in FIGS. 11(a) to 11(C), they can be removed because they do not satisfy any of the selection criteria. This can prevent the output of unreliable reflected waves that contain inaccurate information.

Note that the four types of selection criteria are shown as an example, and the number of selection criteria can be increased or decreased depending on the purpose, use, etc.

The scattered waveform, which is the reflected wave output in this way, contains only echo signals from the parenchyma of the living body, such as the liver.

An example of the display on the display 17 is shown in FIG. In the figure, reference numeral 51 indicates a B-mode image, and reference numeral 52 indicates a beam path 1 to 1 of the set beam path for the cross-mode measurement in this region of interest.
Path markers; 53, beam path route 1 to other A-mode images obtained by the cross-mode measurement; 54, each sound velocity value for each beam path route obtained by the cross-mode measurement; 55, these It is a diagram of changes in average sound speed values of symmetrical parts obtained based on sound speed values for each beam, path, and route. The beam path marker 52 has the above (1) to (
Among these routes, the sound speed value 54 shows the sound speed value of the route (1) above as vl, the route sound speed value of the route (2) above as V2, and the sound speed value of the route (3) above as Vl. The sound velocity value of the route is numerically displayed as V3, and the sound velocity value of the route in (4) above as V4.

Note that ■ is the average sound speed value of these four routes. Reference numeral 56 indicates the waveform minute amount for each rule 1.

Further, 57 indicates a time change in the average sound speed value, and 58 particularly shows a time change in the waveform feature ffl W 1.

In addition, in the ultrasonic wave transmission and reception in the cross-mode sound ring measurement described above, this device detects the movement distance of the center position in the transducer arrangement direction of the transducer group belonging to point A and the transducer group belonging to point D, and the movement distance of the center position of the transducer group belonging to point A and the transducer group belonging to point D, respectively, and point B. (, the moving distance of the center position in all the transducer array directions of the transducer group and the transducer group belonging to the 0 point is the same distance Δy as shown in FIG. 2. The deflection angle θ is θ° in both cases.
and make them equal.

Therefore, as a result, point Pn and point P+2 become point Po.

, and are in a line-symmetrical positional relationship with respect to a line perpendicular to the ultrasound transmission/reception wave surface of the probe 1, and
The distance between them is Δy.

Point Poo, point P112 and point P+2 are the ultrasound reflection points in the internal tissue of the subject, but at the same time A of probe 1
It means the intersection point of the ultrasonic transmission/reception direction by the transducer group bending to the point B, point B, point 0, and point D, respectively.

Therefore, the time t1~ obtained by the above-mentioned ultrasonic wave transmission and reception
Using t4, the calculation circuit 18 is caused to perform the following calculation.

Δt=((tl-t2)+(t3-t4))/2=(
(tI+t3)/2)-((t2+t4)/2)
(5) Δt obtained by executing the dashed line in equation (5) becomes the estimated propagation time value of the ultrasonic wave propagating along the path between point P++→point Poo→point P12.

Therefore, using the calculation circuit 18, point Pa1 → point Poo → point P
The average sound speed CA of the ultrasonic waves propagating along the path between +z and z is determined by the following equation.

To C = Δy-co (Δt-5in o)
”・(6) The average sound velocity calculated by this equation (6) represents the sound velocity in a local area of the internal tissue of the subject (in this case, a region including point P111, point Poo, and point PI2).

In this way, it is possible to calculate the sound velocity locally in the internal tissue of the subject from the ultrasound reflection components at P111 point Poo and point 1123. By appropriately switching the multiplexer 13 and changing the intersection point of the directional directions in the transmission and reception of ultrasonic waves, sound velocities at multiple locations in the tissue within the subject can be determined without changing the deflection angle θ.

FIG. 7 is a diagram showing a region where the waveform feature M and local sound speed can be measured by changing the camera element's l;Tl.

Generally, the element that determines the pointing direction has a delay time within which δ2 can be determined. Therefore, since the above-mentioned intersection point is specified, the marker generator 29 is configured to output a beam path passing through this possible intersection point position as a marker, and when a measurement route is set, Select and output the beam path as a marker.

28A in the figure is a measurable region of waveform characteristics and local sound speed, and symbol Po in this region 28A.

The marks "." with P71 are the intersections of the ultrasonic wave transmission/reception directional directions.

In this case, (Poo, Pt+,
P+2), (P++, P?1. PZ2>,
(P+2. P22. PZ3), (P21. P31
．． P32), (PZ2.P32.P33), (PZ3.
P33. P34) In line with the abnormal area to be measured as shown in the figure, the first intersection point and a line passing through this first intersection point and whose axis is a line perpendicular to the ultrasound transmission/reception wave surface of the probe 1. The second one is located in a symmetrical position. Select a combination of three reflection points at the third intersection, perform the above measurement on the reflected waves passing the route as described above at the three intersections, and (
By determining the average sound speed by calculating the equation 1), it is possible to determine the portion of the average sound speed between the waveform features and the desired local area within the measurable region 28Δ.

The sound speed between the waveform features and the desired local area calculated by the calculation circuit 18 can be displayed as a sound speed valve on the display 17 after being subjected to brightness modulation or color modulation.

In this device, the averaged values are plotted and displayed graphically, but the following averaging may also be performed. This averaging (unsampled average) is calculated by the following equation, which is the number of combinations of intersection points used to calculate the local sound speed, which is 3 in the case of this embodiment.

Alternatively, unsample averaging can be performed as follows.

That is, from each combination of three intersection points, the measured propagation time is set to Δ℃1, and using equation (8), the ultrasonic propagation time is first unsampled averaged, and the average result is the sound velocity value obtained in this way. The unsampled average result is displayed on the display 17 as shown in FIG.

In addition, if you want to see the frozen image, the system control means 2
Give freeze command to 5A. Although not shown, a freeze command switch or the like is provided and operated by the operator. Upon receiving this command, the system control means 2
Immediately after collecting data on all the ultrasonic beam transmission/reception paths used for measurement to obtain the cross-beam ultrasonic waveform and sound velocity information, the control unit 5A controls to sequentially freeze the obtained ultrasonic determined images. Then, the measured sound speed values for each route are obtained and displayed on the display 17 as shown in Fig. 6, and the average value and variance value of 59.60 between the waveform features and the sound speed values displayed on the time change diagram are plotted and displayed. do.

Since the displayed images at this time, including the B-mode image, are almost the same in time, if they are recorded and saved, they are extremely useful as comprehensive measurement data at the time.

When the freeze command is released, the measurement display returns to the normal mode described earlier, and the mode image display in real time and the waveform 1'! The in and sound speed measurement data are sequentially updated.

Although the embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above and shown in the drawings, and may be practiced with appropriate modifications within the scope of not changing the gist thereof. be.

[Effects of the Invention] As described above, according to the present invention, the reflected wave by the cross beam method is compared with the selection criteria, and if an artifact component is included, this foul wave is removed.
Accurate diagnosis can be made.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an ultrasonic diagnostic apparatus according to an embodiment of the present invention, Fig. 2 is a diagram for explaining the principle of this apparatus, and Figs. 3 (a) and (b) are ultrasonic diagnostic apparatuses of the present invention. Figures 4(a) to (C) are scattered waveform diagrams showing the waveform selection principle of the present invention, and Figure 5 is a normal display example obtained by the ultrasonic diagnostic apparatus of the present invention. FIG. 6 is an example of a display display obtained by the ultrasonic diagnostic apparatus of the present invention during freezing, FIG. 7 is a diagram for explaining the measurement point setting area on the probe of the ultrasonic apparatus of the present invention, and FIG. 8 is a diagram for explaining the principle of the cross beam method, Figure 9 is a time chart showing the method for measuring the propagation time of an ultrasonic beam, Figure 10 is a diagram for explaining the spread of the cross beam, and Figure 11 ( A) to (C) are conventional scattering waveform diagrams. 1... Probe, 13 multiplexer, 14...
Pulsar, 15...Delay circuit for transmission, 16...Delay circuit for reception, 17...Display, 18...Calculation circuit, 19.27...Reception circuit, 20.28...A/
D converter, 21... Clock excavator, 22... Memory, 23.
...Processing circuit, 24...Waveform analysis circuit, 25△...
System control means, 26... changeover switch, 29... marker generator,
30...Digital scan converter, 31.
...Cross mode measurement area setter, 51...B mode image, 52...Ultrasonic beam path, 53...A mode image, 54...Sound velocity value, 55...Average sound velocity value, 56
... Waveform feature amount, 57... Time change chart of average sound speed value, 58... Time change chart of 'tan' when waveform, 59.60.
...Dispersion value. Agent Patent attorney Nori Chika Ken Canzhou Dai Ko Norifu Figure 2 ↑ (Time) t (Time opening) (b) Figure 3 Figure 7 Funeral Figure 9

Claims (3)

[Claims] (1) Using a probe configured by arranging multiple ultrasonic vibrating elements in parallel, a predetermined number of adjacent ultrasonic vibrating elements of this probe are grouped, and a selected group of ultrasonic vibrating elements is used. The ultrasonic beam is transmitted and received through multiple ultrasonic wave transmission and reception paths, and the ultrasonic beam is transmitted and received to obtain an ultrasonic image, which is displayed on a display. Ultrasonic tissue characterization of the target area is performed by transmitting and receiving ultrasonic waves using a group of ultrasonic vibrating elements for transmitting and receiving different ultrasonic beams and detecting reflected waves from the target area. In an ultrasonic diagnostic device that obtains information and displays it on the display for diagnosis, the reflected wave obtained from the target area is compared with a plurality of preset waveform selection criteria, and all waveform selection criteria are selected. An ultrasonic diagnostic apparatus characterized by comprising a waveform selection means that outputs a waveform only when the following is satisfied. (2) The ultrasonic diagnostic apparatus according to claim 1, wherein the waveform selection means uses a value obtained by lowering the waveform peak value of the reflected wave by a predetermined level as the comparison value. (3) The ultrasonic diagnostic apparatus according to claim 1, wherein the waveform selection means uses a sound velocity value at a waveform peak value of the reflected wave as a comparison value.