JPS62170232A - Ultrasonic diagnostic apparatus - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an ultrasound diagnostic apparatus for diagnosing tissue within a subject using ultrasound, and in particular for diagnosing tissue by measuring the ultrasonic propagation velocity of the tissue. The present invention relates to an ultrasonic diagnostic device equipped with sound velocity measurement and display functions for characterizing and diagnosing the same.

[Technical background of the invention]

The ultrasonic propagation velocity in a subject is influenced to a large extent by the composition present in the ultrasonic propagation path in the subject.

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 ultrasonic propagation velocity. Measuring velocity has great clinical value.

Therefore, attempts have been made to utilize this fact to obtain information on the ultrasonic propagation velocity in the living body and use this information to inspect the composition at a target position.

Conventionally, as a practical ultrasonic measurement method for such examinations, a method as shown in FIG. 7 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 using this probe 1, ultrasonic pulses are emitted into the body in the θ direction from one end A of the ultrasonic examination surface 2 that is in contact with the body surface (not shown). fire.

Here, the electronic scanning type ultrasound device uses a probe with an ultrasound transducer array in which a plurality of ultrasound transducers (hereinafter simply referred to as transducers) are arranged in parallel. A drive pulse is applied to each group of transducers with a predetermined delay time determined according to the direction of the transmitted pursuit sound beam and the position of the transducers in the group. , which excites ultrasonic waves, and 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 other areas, resulting in ultrasonic waves. This is a method to obtain a beam. Wave reception is generally performed using the above-mentioned group of transducers used for wave transmission, and the detection signals of the transducer group are delayed by the delay time during wave transmission to align the time axes, and then synthesized. Let it be the received signal. By shifting the group of transducers by -pitch, the position of the generated ultrasonic beam shifts. Therefore, by electrically selecting the transducers to be excited and controlling the excitation timing, linear - Scanning can be performed, and sector scanning can be performed at desired locations.

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, out of this reflected wave (eco~),
Echoes arriving at the probe 1 following the delivery route 5 are received by the transducer group at the incident position of the echoes that have arrived (the transducer group at the right end B of the probe 1), rather than by the transducer group that was used for transmission. .

Since the distance y between A and B is known, if the propagation time t of the ultrasound propagating along path 4.5 is measured, the sound speed C in the liver tissue is c=y/(t-3i nθ) −( 1).

This principle is used to measure the speed of sound.

Since the speed of sound is unknown, θ is strictly unknown, and
Since there is no reflection point such as point P in a living body, various measures must be taken to obtain the speed of sound from equation (1) above. Therefore, an apparatus using this method has a configuration as shown in FIG.

In the figure, reference numeral 1 denotes an ultrasonic probe, for example, a 128-element transducer T1.1 that transmits and receives ultrasonic waves. -T128 are linearly arranged in parallel to form the probe 1. Transducer TI
, ~T128 The juxtaposed surface corresponds to the ultrasonic wave transmitting/receiving surface 2 of the probe 1 in FIG.

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;
4 is a pulser that generates pulses for ultrasonic excitation drive, 1G
17 is a receiving delay circuit for obtaining the echo delay amount necessary for aligning the time axis etc. according to the receiving direction and element position for each of the group of transducers used for reception, and 17 is a receiving delay circuit for obtaining image, text information, etc. 18 is a calculation circuit, 19 is a transducer TI obtained through a reception delay circuit 16,
- A receiving circuit that synthesizes, amplifies, and detects the received echo signals from T128, performs logarithmic conversion, corrects the signal level according to depth, and outputs it as a received signal; 20 converts the received signal into a digital signal; An A/D converter 21 is an oscillator 22 that generates a rate pulse signal for driving the balsa and a clock signal for sequentially updating addresses for the memory in order to sample and store the echo from the target part of the subject. 23 is a memory for storing received signals, and 23 adds the stored data value at the same address of the memory 22 and new input data every time an ultrasonic pulse is generated, averages it, and stores the added average value at the corresponding address. A processing circuit 24 examines data indicating a peak value using the sample values of the received waveforms that have been subjected to the averaging process and is stored in the memory 22, and from this determines the time (address) of the data having the peak value. This is a waveform analysis circuit. The calculation circuit 18 calculates the propagation time t from the time information obtained by the waveform analysis circuit 24, and calculates the speed of sound at a plurality of localities in the internal tissue of the subject based on the obtained propagation time t, and, It has a function to spatially average and output these. This calculation result is then displayed on the display 17. 25 is a system control means, which is mainly configured with a CPU (Central Processing Unit; for example, a microprocessor). The system system means 25 controls the operation of the multiplexer 13, sets the delay times of the transmission delay circuit 15 and the reception delay circuit 16, and controls the memory 2 according to a predetermined program.
2 and controls the operation of the calculation circuit 18.

The transducers TI to T128 are excited and emit ultrasonic pulses when a voltage pulse is applied to them, and generate a voltage when the ultrasonic pulse is incident. 128-element vibrator T1.
~T128 is, for example, the element width a of each vibrator is 0.67#
This is the pitch between element centers d=o, 72m
128 elements are arranged linearly at intervals of . Electric signals are sent and received to and from each of these vibrators through lead wires 12 within the cable 3.

Further, the oscillator 21 generates, for example, a 10 MHz reference clock, divides the frequency of this clock, converts it into a 4 kHz rate pulse, and outputs the pulse. This rate pulse passes through 32 transmission delay circuits 15 and drives 32 balsers 14. The balsers 14 are circuits that generate pulses for ultrasonic excitation driving, and the outputs of these 32 balsers 14 are sent to 128 transducers T11. ~T128, TI at the A end, ~T32
are input in a one-to-one correspondence.

Further, the transducers TI, to T128 are in contact with the body surface through the coating material of the pronib 1, and the ultrasonic waves output from the transducer elements are propagated into the living body.

Standardly, the speed of sound in living tissue is C, = 1530 [m/S]
Then, in order to radiate the ultrasonic beam in the θ0 direction, the delay time between adjacent elements τ0τo=(d/Co)・sin
θo-(2), and the transmission delay circuit 15 is set so that each element is driven with such a delay time difference.

That is, PD1=O, PC)2=TO, PD3=2
τ0, . . . A delay time of P D 32=32τ0 is given.

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=S r nθo/Co from Snell's law.
- The value shown in (3) is obtained.

After emitting the ultrasonic pulse, the multiplexer 13
The vibrating element T97. The ultrasonic reflected wave signals received at ~T128 are delayed in the same way as in the case of transmission, are synthesized, and are input to the receiving circuit 19. Here, reception delay circuit 1
The delay time of 6 is RD1=31τ0, RD2=30τo
, −, RD31=τo, and RD32=0.

In this way, even if the ultrasonic beam transmitted in the θ0 direction at the sonic speed Co becomes C in the living body and has directivity in the θ direction, the transducer element group T91. ~T128 has directivity in the θ direction, and θ
It will receive reflected waves from the direction. The received signal is amplified, detected, and logarithmically converted in the receiving circuit 19, and is also A/D
The converter 20 converts A/
The data is converted into D and stored in the memory 22. The address of the memory 22 is updated sequentially in synchronization with a 10MH2 clock based on the timing of the rate pulse, and the address of the sample value of the received waveform stored in the memory 22 is updated in time from the ultrasonic pulse emission time, for example. They match exactly with an accuracy of 100 ns intervals. Therefore, from the address, the time when data at that address was obtained (the elapsed time from the time when the ultrasonic pulse was emitted) can be determined.

The peak value of the stored waveform indicates the reflected wave from point P,
If the waveform analysis circuit 24 detects the time (address) of the peak value, the propagation time t can be determined. Substituting the above-mentioned equation (3) into equation (1) yields the sound speed C in the living body. Furthermore, in equation (4) (
2) Substituting the formula, C= -no y-d/l ・τ
0...(4-). y, d, τ0
Since C is known, the calculation circuit 18 calculates the above equation 4' using the propagation time t obtained by measurement to obtain the value of the sound speed C, and outputs it to the display 11.

FIG. 9 is a time chart showing a method for measuring the propagation time t, 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
A reflected wave having a peak at t2 is obtained, and t is determined as the time interval between t2 and tl. It is possible to adjust the probe so that blood vessels in the liver are placed at point P, but since the target is a living body, there is something equivalent to a point reflector at the intersection of the beams. This is rare.

Generally, when the observation site is, for example, the liver, the vicinity indicated by point P is relatively uniform liver tissue.

Therefore, the reflected wave from the vicinity of this point P becomes a relatively uniform reflected wave from the liver tissue. Since the ultrasonic beam has a thickness, among the reflected waves mentioned above, the one that reaches the earliest is the one that goes through the 91 points in Figure 9, and the one that arrives the latest is the one that goes through the 12 points. becomes. Therefore, the received waveform spans a period of time corresponding to the width from Pl to P2.

Therefore, the received waveform in this case spreads as shown in Figure 9(b), and since the tissue is not completely uniform and is a living tissue, various scattered ultrasound waves are formed and interfere with each other. The received speckles are included in the resulting speckles, so
Various random irregularities will occur in the waveform.

Therefore, the peak value cannot be detected with this method, so by moving the probe a little, we obtain echo data that slightly shifts the position of the beam intersection in the liver, and add these together to cancel out the noise component. Do it like this. In other words, since the unevenness of the waveform in (b) is considered to be random, the waveform can be made considerably smoother by changing the beam intersection and adding several hundred or more matching times, or by performing peak hold processing. Like (C)
Ru.

Alternatively, instead of the above method, curve fitting may be performed by the least squares method using a unimodal function with one peak, and this also allows replacement with a completely smooth curve as shown in (d). I can do it.

Next, the calculation circuit 18 calculates the propagation time t as t=t2-tl.

Now, using 3.5MH2 as the ultrasonic frequency, y=48
m, and if the ultrasonic beam is focused near the intersection point P, the beam width near the point P (about 17% at the peak in transmission and reception) is about 2M.

At this time, the propagation time difference Δt between the one passing through 91 points and the one passing through 12 points is about 4.5 μs.

When C=Go, the ultrasound beam direction is θo
=30°, the propagation time t is approximately 62.7 μs. Since the measurement accuracy at time t2 of the peak value is considered to be less than 1/10 of Δt, the sound speed measurement error is theoretically 10 m.
/S or less.

The sound speed measured in this way is the path 4 and 5 in Figure 7.
This sound speed information is displayed on the display 17 together with an ultrasound B-mode image (tomographic image) near the liver, which is the examination site in this case, and is used for diagnosis.

The above method is for determining the average sound velocity in the tissue near the point P, but if the above-mentioned method is further improved, it is also possible to measure the local sound velocity. The method will be shown using FIG.

FIG. 11 is an explanatory diagram of a case where the ultrasound transmitting/receiving surface 2 of the tube O-bu 1 is applied to the abdominal body surface and a normal electronic scan is performed on a cross section 32 of the liver. A B-mode image 30 obtained by electronic scanning is displayed on the display 17, and the propagation path set for sound velocity measurement is also displayed superimposed on the B-mode image using a marker. 31 is the subject's fat and muscle layer; 32 is a cross section of the liver showing the liver parenchyma; 33 is the diaphragm; and 34 is abnormal tissue (for example, tumor) within the liver.

There is no problem with the above method when measuring the average sound velocity in the liver parenchyma 32, but when measuring the average sound velocity in the liver parenchyma 32,
When trying to measure the sound speed of four parts, it is inconvenient to use the average sound speed of the liver tissue including the 34 parts of the abnormal tissue.

In this case, the ultrasonic measurement point (intersection position of beam direction directions for both transmitting and receiving) is abnormal group 113 indicated by PI and PO.
The transmitting and receiving position of the ultrasonic wave is determined so that it is located at the boundary point of the four parts. At this time, the above measurement points P1, P with probe 1
The extension line position of O is indicated by ○, and the emission points of the probe 1 are A and B in the propagation path of the ultrasound beam with 91 points as measurement points.

The incident points are B and ○, the emission points in the propagation path of the ultrasonic beam with the PO point as the measurement point are C and D, the incidence points are D and 0, and the measurement point pi at the probe 1,
Let the extension line position of po be O, and the propagation path passing through each of these points (A-B, A-+O, B→O, CD, C-0, D-
0) F(7) 1fflt(AS>, t (80) during propagation
, t (BO), t (CD).

Find t (Co) and t (Do).

In addition, the round-trip ultrasonic propagation time between Pl and PO is t2,
APO is the ultrasonic propagation time between A-4PO.

The ultrasonic propagation time between PO → B is POB, PO-+.

The ultrasonic propagation time between POO, C-IP1 is CPI, the ultrasonic propagation time between P1 → DP1 is PID, the ultrasonic propagation time between P1 → 0 is Plo,
Using these, t(AB>.

t (AO), t (BO), t (CD).

Calculate t (Co) and t (Do). That is, t
(AB)=APO+POB t (AO> -APO+ (t l, /2) +P
10t (BO) =BPO+ (t R/2) +
P10t (CD)=CP1 +PI D t (Co)=CP1 +P10 t(Do) -DPI +P10 (5) From this, tR can be found using the following equation.

J = [(t (AO) + t (BO) - t (AS)
) - (t (Go) + t (Do) - t (CD))] ... (C6 Therefore, the distance between pi and po is ×2, and the average sound speed is 0°C
, the distance between AB is yo, and the distance between cD is yl, (12=2)l/1ffi = (VO-1)/(tM・tanθ)...(7) Xffi= (yo -yl) / 2tanθ...
(8) The local speed of sound C°C can be found as follows. As the value of θ, using the average sound speed C of the normal liver portion, θ=S! from equation (3).
n-' ((C/Co) ・s i ner3
)...(9) may be used as an approximation formula. In reality, the ultrasound beam is refracted at the boundary with normal liver tissue, so equation (7) is not exact, but if the beam incidence on the boundary is close to perpendicular, the error will be small. Note that this error can also be corrected by calculation based on the angle of incidence.

In this way, the sound velocity information of the region of interest is obtained, and the text information (
In Fig. 11, C1 indicates the sound velocity in the liver parenchyma and C2 indicates the sound velocity in the abnormal region), and the B-mode image and the measured ultrasound propagation path are displayed on the display together with display markers. Save by recording a video.

This type of sound velocity measurement is called cross-mode sound velocity measurement, but in the case of the above-mentioned method, A, B, and C at probe 1 are
, D, the propagation path (A→B, A→O, B−+
The propagation time in a total of six propagation paths (O, CD, C-0, D→O) was measured to determine the local speed of sound. By measuring the three paths for one measurement point in this way, we can measure the influence of the abdominal wall (due to differences in the thickness of the body surface and subcutaneous tissue) caused by the ultrasound beam entering and exiting obliquely. The accuracy is improved by reducing the influence of

However, 8! ! The thickness of the wall is not uniform, and the physical conditions during the outward and return journeys to the measurement point are also different, and this causes differences in the attenuation of sound waves and measurement timing on each route. Each measurement value includes an error amount due to factors such as the influence of biological movement associated with deviation.

In the above method, this error is reduced by weighted averaging using measured values from various routes, but contrary to the original purpose, in the case of the above three route force formula, it is difficult to The problem remains that the above error cannot be strictly reduced because the average is statistically non-uniform due to the asymmetric measurement in which the measurement along the path from A to D is missing and from D to C. Ta.

Therefore, for each ultrasonic beam transmission/reception path used for the above-mentioned measurement of the object, control is performed so that the above-mentioned detection measurement is performed at least once each with the outgoing direction and the backward direction as a set, and thereby - per path, Perform detection measurements an even number of times (at least two round trips) with the transmitting and receiving directions reversed to ensure symmetrical measurements, and calculate the average ultrasonic propagation velocity based on the information obtained from these detection measurements. A cross-mode sound velocity measurement method using a symmetric measurement method has also been proposed, which aims to reduce errors by obtaining a uniform average.

Specifically, as shown in Figure 2, this method consists of reflection points (measurement points) Plt and Pt2 at the upper boundary, reflection points (measurement point > local sound velocity of the abnormal part included in PIIO) at the lower boundary, and In measuring the ultrasonic beam transmission and reception path (l
l A-+Pa a →B, (2) A-+P1
s-+C, (3B-+P++ D-)A, (4)
Try to take four routes: Pt 2 → D. That is, each of the A and B positions of the probe 1 is used as an ultrasonic beam transmission position and also as a delivery position. Then, the wave is transmitted from position A, the wave reflected at Pa a is received at position B, then the wave is transmitted from position A, the wave reflected at Pls is received at position C, and then the wave is transmitted from position 8. By switching the transmission and reception such that the wave reflected by Pao is received at position A, then transmitted from position B, and the wave reflected at Pt2 is received at position D, the measurement path can be changed. The aim is to provide symmetry and to make the directivity directions of the ultrasonic beams in the transmitting and receiving directions 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 loss mode sound velocity measurement function is built into an ultrasound diagnostic device, and is usually used to measure ultrasound images (for example, B-mode images).
displayed on the display.

This situation is shown in FIG. In the figure, 40 is an 8-mode image of the subject's region of interest measured in real time; 41
is a beam path marker indicating the route of the set beam path for the cross-mode sound velocity measurement in this region of interest; 42 is a real-time A-mode image for each beam path route obtained by the cross-mode sound velocity measurement; 43
is the beam obtained by the above cross-mode sound velocity measurement.
Each sound speed value for each path/route, 44 is a diagram of changes in the average sound speed value of the target region determined based on each sound speed value for each beam, path, or route. The beam path marker 41 indicates the routes (1) to (4) above, and also indicates the speed of sound @
33 is the sound speed value of the route (1) above among these routes, ■1, the sound speed value of the route (2) above is v2,
The sound speed value of the above route (3) is numerically displayed as V3. The sound speed value of the route of the above (gradient route) is numerically indicated as ■4.
is the average sound speed of these four routes. Further, the average sound speed value change diagram 44 shows the time change of this average sound speed value. In addition, the A-mode image 42 has roots (1) and (3) as 81.83, and roots (2 and (4)) as 81.83.
The one shown below is displayed as 82, B4.

When displaying such an image, the B-mode image 40 is rewritten in real time under the control of the system control means, and in between, cross-mode sound velocity measurements of the four routes mentioned above are performed. The calculation circuit 18 performs calculations and displays the measurement results. The A-mode image is displayed using echoes obtained by cross-mode sound velocity measurements.

[Problems with background technology]

By the way, in such a loss mode sound velocity measurement, the ultrasonic beam is scattered by various scatterers in the transmission and reception paths, and the measurement signal fluctuates greatly due to interference (speckle) caused by these scattered waves. are doing. From this fluctuating measurement signal, as shown in Fig. 9(d),
In this method of determining the position of the peak value and measuring the above-mentioned propagation time t, the accuracy varies greatly depending on the position of the determined peak value. This directly affects the accuracy, stability, and reproducibility of the estimated sound speed.

As shown in FIG. 13, as a method for stabilizing the signal with large fluctuations, many sample signals 81. ~3n
There is a method to obtain the average Sa. However, if too many sample signals are obtained, real-time performance is lost. On the other hand, if we focus on real-time performance, we will end up detecting peak values of data such as a and b in Figure 14, which have fluctuations that are not sufficiently averaged, and will show different values no matter how many times we measure the same part. This leaves problems with measurement stability.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and its purpose is to perform highly accurate and highly stable measurements with a small number of samples in an ultrasonic diagnostic apparatus having a cross-mode sound velocity measurement function. It is an object of the present invention to provide an ultrasonic diagnostic apparatus with a cross-mode sound velocity measurement function, which can further maintain real-time performance and improve cross-mode sound velocity measurement accuracy.

[Summary of the invention]

That is, in order to achieve the above object, the present invention uses a probe configured by arranging a plurality of ultrasonic vibrating elements in parallel, and sets a predetermined number of adjacent ultrasonic vibrating elements of the probe into a group, and In order to transmit and receive ultrasound beams to the target site using multiple ultrasound transmission and reception paths, a group of ultrasound transducer elements for transmitting and receiving different ultrasound beams are used to transmit and receive ultrasound beams. The ultrasonic wave propagation velocity information of the target area is obtained by detecting the reflected wave from the target area and measuring the time required from transmission to reception of the wave, and is equipped with a sound velocity measurement function for diagnosis. The ultrasonic diagnostic apparatus is characterized in that it is provided with a filter that is used to measure the speed of sound and extracts low frequency components of the received signal of the ultrasound beam, and that the extracted received signal is used to measure the speed of sound.

In such a configuration, the ultrasonic beam reception signal for cross-mode sound speed measurement is passed through a filter to extract low frequency components, and the low-frequency components are extracted and used for sound speed measurement. In other words, by performing such filtering processing, high-frequency noise components such as speckles that can cause misidentification of peak position detection are removed, and multiple received signals that have been subjected to this filtering processing are collected and added together. By detecting the peak position based on the averaged waveform, it is possible to accurately detect the peak position and to perform highly accurate sound speed measurement. In addition, by performing filtering processing to remove high-frequency noise components, the peak position can be detected with high accuracy even if the number of times of averaging is reduced, so the measurement time can be shortened by reducing the number of samples. ,
As a result, it becomes possible to perform highly accurate sound speed measurements without impairing real-time performance.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the main structure of this device. In the figure, 1 is a probe, 12 is a lead wire, 13 is a multiplexer, 14 is a balsa, 15 is a transmission delay circuit, 16 is a reception delay circuit, 17 is a display, 19 is a reception circuit, 2
0 is an A/D converter, 21 is a clock oscillator, 22 is a memory, 23 is a processing circuit, and 24 is a waveform analysis circuit. These are basically the same reference numerals in FIG. 8 as explained earlier.
It is the same as the one with the same name, so it will not be explained again here.

18 is a calculation circuit that calculates the speed of sound and average value based on the output of the A/D converter 20, and 25A is a system control means that controls the entire system. Reference numeral 26 denotes a changeover switch, which selects and switches the supply route of the combined output of the receiving delay circuit 16 to the cross-mode sound velocity measurement side X and the ultrasonic device side B for obtaining an ultrasonic B-mode image. 21
is a receiving circuit on the ultrasonic device side, which performs amplification, detection, logarithmic conversion, etc. of the received signal. 28 is an A10 converter, which converts the output of the receiving circuit 27 into a digital signal. A marker generator 29 generates image data for displaying the measurement route (beam bus route) of the cross-mode sound velocity 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 11, 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 this frame memory. . Further, the output of the marker generator 29 is written into the frame memory of the digital scan converter 30 at a position corresponding to the measurement route of the cross-mode sound velocity measurement of the B-mode image.

Moreover, 31a, 31b, and 31c are low-pass filters that filter the output signal of the receiving circuit 19, and are O-bus filters each set to a different cutoff frequency. 32 are these low-pass filters 31a,
This is a selection switch for selecting either one of the filters 31b and 31c, and is used to provide the output of the low-pass filter selected by the selection switch 32 to the A/D converter 20.

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 which is a display image memory, and displays graphs of the sound speed data, A-mode image, change pattern of the average sound speed, etc. calculated by the calculation circuit 18. The control means 25A controls the data to be stored in a predetermined layout and in a predetermined format. The image data on this video RAM and the digital scan converter 30
Display an image based on the output of .

This device is basically the same as that described in the prior art with regard to cross-mode sound velocity measurement, but this device has the configuration shown in FIG.
The function is set as follows. The system control means 25A used in this apparatus is the same as the conventional system in that it is mainly configured with a CPU (Central Processing Unit; for example, a microprocessor). This system control means 25A controls the multiplexer 1 according to a predetermined program.
3, the setting of the delay time of the transmission delay circuit 15 and the reception delay circuit 16, the writing and reading control of the memory 22, the operation side of the calculation circuit 18, the switching control of the changeover switch 26, and marker generation. Vessel 29
This controls marker output control, etc.

While ultrasonic scanning is normally performed for B-mode, it is controlled to transmit and receive ultrasonic waves for cross-mode sound velocity measurement in between (every predetermined timing), and the real-time display of B-mode and sound velocity are controlled. Calculate the measurements and display the results, and calculate and plot the average sound speed of the entire beam bus.

In addition, if you want to display A-mode, freeze the B-mode image when the B-mode scan is completed, then perform cross-mode sound velocity measurement, calculate and display the sound velocity, and display the cross-mode sound velocity. Display of frozen A mode image based on measurement data on beam bath, average A
A mode image is displayed, and an average sound speed change diagram or a local sound speed change diagram of one selected beam bus is displayed.

Regarding the cross-mode sound velocity measurement, for example, if a symmetric measurement method is used, the operation of the multiplexer 13 is controlled as follows.

That is, as shown in Fig. 2, in this device, the reflection point (measurement point) Pl and Pt 2 at the upper boundary, the reflection point at the lower boundary and the local sound velocity of the abnormal part included in the measurement point > Po a. When measuring, the ultrasonic beam transmission and reception path is A-
+Po o-+B, A-+Pt 1→C, B-+Po
Try to take four routes: a +A, B-+Pt 2 →D. That is, each of the A and B positions of the probe 1 is used as an ultrasonic beam transmission position and also as a delivery position. Then, the wave is transmitted from position A, and Pa a
The wave reflected by is received at position B, then transmitted from position A, the wave reflected by Pll is received at position C, then transmitted from position B, and the wave reflected by Pan is transmitted from position A. By switching the transmission and reception such that the wave is received, then transmitted from position B, and reflected by PI3 is received at position D, the measurement path is symmetrical, and the ultrasonic beam The directivity directions of the transmitting and receiving directions are set to be the same angle θ.

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

In this embodiment, the cross-mode sound velocity measurement is performed using four routes B1, B2, and B3 as shown in FIG.

B4 is used for measurement, and each reflection point is preset by the operator at an optimal depth close to the target region by referring to the B-mode ultrasound image. Then, at a predetermined timing between the ultrasonic electronic scans in mode B, the changeover switch 26 switches from the terminal B side to
side and a sound velocity measurement is taken.

To explain specifically, first, the system control means 2
At 111 m of 5A, the selector switch 26 is connected to terminal B.
Also, the multiplexer 13 is selected for linear electronic scanning, and the delay circuits 15, 16 are set with delay times for linear electronic scanning, and with these delay times, the multiplexer 13 is selected for linear electronic scanning.
Ultrasonic waves are transmitted and received from the selected transducer group No. 3. The combined output of the received signals is layer width-detected by the receiving circuit 27, converted into digital data by the AID converter 28, and inputted to the digital scan converter 30. Then, the digital
Store data in the frame◆memory location of the scan converter 30. While sequentially shifting the scan position, these ultrasonic scans are sequentially processed to form ultrasonic B7 to D images in the digital scan converter 30. In addition, the beam bus marker for cross-mode sound velocity measurement set by the two marker generators is output, and is applied to the position corresponding to the cross-mode sound velocity measurement position in the frame memory of the digital scan converter 30. Markers are stored. The image data thus formed on the frame memory of the digital scan converter 30 is read out in accordance with the scanning of the display 11, and is provided to the display 17 for display.

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

Then, cross mode sound velocity measurement begins. This sound velocity measurement is first performed on route B1.

That is, under the control of the system control means 25A,
The delay time of the transmission/reception delay circuit 15 is set.

This delay time is determined by the delay time difference τ0 between adjacent oscillators as τo=(d/Go)Sinθ0 (formula (2) above)
The relationship is set as follows. Under the control of the system control means 25A, a predetermined number of transmitting vibration elements belonging to point A of the probe 1 are connected to the output ends of the corresponding pulsers 14 by the switching operation of the multiplexer 13.

For example, if the predetermined number of transmitting transducer elements belonging to point A of probe 1 at this time is 32, transducer group T
I, ~T32 and the output end of the pulser 14 are connected.

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
An excitation pulse is output at a timing shifted by a delay time of 5, and is input to the corresponding transducer of the pulser among the transducers TI 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 under the control of the system control means 25A, a predetermined number of reception By the switching operation of the multiplexer 13, the vibrating element is connected to the input terminal of the corresponding delay circuit 16.

Here, since there are 32 transmitting transducer elements, the 32 transducer groups belonging to point B of probe 1 T97° to T12
8 and the input terminal of the reception delay circuit 16 are connected.

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

The reception echo synthesis output from this reception delay circuit 16 is
After being amplified and detected by the receiving circuit 19, one low-pass filter 31a (~33C) is connected by the selection switch 32 selected by the operator (the depth of the beam intersection at this time, the aperture width (transmission, reception) A low-pass filter having an optimum cutoff frequency determined empirically or clinically depending on the distribution width of a group of ultrasonic transducers (distribution width of a group of ultrasonic transducers used for filtered through. The filtered received echo synthesis output is then converted into a digital value by the A/D converter 20 and written 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 control is performed by the system control means 25A, and the echoes from the measurement points are stored in a form corresponding to time. This becomes A-mode image data.

The above-mentioned ultrasonic transmission and reception is concentrated within the selection period of this mode by the transducer groups belonging to points A and B of the probe 1 (or at several times in the selected mode from next time onwards). (using ultrasonic transmission and reception), the received echoes obtained through this measurement are averaged over those of the same route by the action of the processing circuit 23. Ru.

When this work is completed, the system control means 25A switches the changeover switch 26 to the terminal B side again, and starts collecting B-mode images. Then, at a predetermined timing, the system control means 25A switches the changeover switch 26 to the terminal X side, and
Let's move on to measuring the cross-mode sound velocity in route 2.

Then, the multiplexer 13 is operated under the control of the system control means 25A, and this time, instead of the transducer group belonging to point B, the predetermined number of transducer groups belonging to the 0 point of the probe 1 and the corresponding reception It is connected to the input end of the delay circuit 16, and a predetermined number of vibrator groups belonging to point A of the probe 1 are connected to the corresponding balsers 14, respectively. Then, the reflected component at point P1t of the ultrasonic wave transmitted from the transducer group belonging to point A of probe 1 is received by the same number of transducer groups belonging to point 0 of probe 1 as at the time of transmission. 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 after filtering by a low-pass filter, the time t2 from the transmission of the ultrasonic wave on the route B2 to the delivery is measured. served.

When this work is completed, the system control means 25A switches the changeover switch 26 to the terminal B side again, and starts collecting B-mode images. Then, at a predetermined timing, the system control means 25A switches the changeover switch 26 to the terminal X side, and
Let's move on to measuring the cross-mode sound speed along the route.

Then, the multiplexer 13 is operated under the control of the system control means 25A, and this time, the group of transducers belonging to point A is changed to a group of transducers belonging to point B of the probe 1, and a predetermined number of transducers corresponding to the setting depth of the reflection point (the Transmitting transducer group T91.32 (in the example, 32 elements). ~T128 and their corresponding pulsar 14
Further, instead of the transducer group belonging to point 0, a transducer group of 32 elements belonging to point A of probe 1 is connected to the receiving delay circuit 16. And probe 1
Ultrasonic waves are transmitted from the transducer group belonging to eight points, and the reflected components of the transmitted ultrasonic waves at point Poo are received by the transducer group belonging to point A 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 t3 from transmitting the ultrasonic waves to receiving them in the loops 1 to B3.

When this work is completed, the system control means 25A switches the changeover switch 26 to the terminal B side again, and starts collecting B-mode images. Then, at a predetermined timing, the system control means 25A switches the changeover switch 26 to the terminal X side, and
Let's move on to measuring the cross-mode sound speed along the route.

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 predetermined number of transducer groups belonging to point D of the probe 1 are connected to the corresponding input terminals of the reception delay circuits 16, Further, the predetermined number of vibrator groups belonging to point B of the bus 1 are connected to the corresponding pulsers 14, respectively. Then, the transducer group and the input terminal of the receiving delay circuit 16 are connected. When an ultrasonic wave is transmitted from the transducer group belonging to point B of probe 1, the reflected component of the transmitted ultrasonic wave at point P12 is received by the transducer group belonging to point D of probe 1. be done. Then, the reception echo is transmitted to the reception delay circuit 16.
The signals are synthesized and output after being given the same time difference as in the case of wave transmission.

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 changeover switch 26 to the terminal B side again, and starts collecting B-mode images. Then, at a predetermined timing, the system control means 25A switches the changeover switch 26 to the terminal X side, and
Let's move on to measuring the cross-mode sound speed along the route. These operations are repeated to display a real-time B-mode image and average the cross-mode sound velocity measurement data.

In this way, it is added and averaged a predetermined number of times (see Figure 5).
The stored data that has been filtered by the low-pass filter is read out from the memory 22, data indicating its peak is examined by the waveform analysis circuit 24, and information on the address where the data is stored is sent to the calculation circuit 18 as time information. sent to. Based on this, the calculation circuit 18 calculates the time t1.81.82.83 from the transmission of the ultrasonic waves to the above-mentioned peak for each route of B4. t2
.

t3. t4 is calculated. Thereafter, the sound speed values Vl, V2, V3, V4 for each route and the average sound speed V for all beam buses are further calculated and displayed on the display 17.

Therefore, in the normal state, only the B-mode image, the measured sound speed, and the average sound speed time change diagram are updated and displayed one after another. Other items, such as A-mode images, are only displayed when frozen, except for those that are already displayed.

An example of the display on the display 17 is shown in FIG. In the figure, 51 is a B-mode image, and 52 is the above-mentioned cross at this region of interest.
Mode sound velocity measurement setting Beam bus marker indicating the beam bus route, 53 is a frozen A mode image for each beam bus route obtained by the above cross mode sound velocity measurement, 54 is the above cross mode sound velocity measurement Each sound speed value for each beam bus route obtained by 55 is a change diagram of the average sound speed value of the target region determined based on each sound speed value for each beam bus route. The beam bus marker 52 indicates the routes (1) to (4) above,
Among these routes, the sound speed value 54 is Vl, the sound speed value of the route (1) above, V2, the sound speed value of the route (2), V3, the sound speed value of the route (3) above, and V3, the sound speed value of the route (3) above. The sound speed value of route 4) is numerically displayed as ■4. In addition, ■ is the average sound speed value of these four routes. Also, 56 is the dispersion value, and 57 is the average A-mode image of each route. In addition, the above average sound speed value change diagram 5
5 shows the time change of this average sound velocity value. In addition, the A mode image 53 is Bl
, 83, and the root (′2J and (4)) as 82
, B4.

In the above system, the low-pass filters 31a to 31c
The cutoff frequency is set within 1/10 Ts x fC x 110.3 Ts, with Ts being the spread of the scattered waveform of the ultrasound beam, in order to obtain a sufficient smoothing effect and prevent the waveform from being excessively rounded.

Incidentally, the spread Ta of the scattered waveform may be determined experimentally or may be obtained approximately from the beam spread and deflection angle of the system. For example, consider a system that transmits from point A and receives at 8 points as shown in Figure 10 (a).The aperture width of a group of ultrasonic transducers used for transmission and reception is d, the deflection angle is θ, and the beam intersection When the depth is 2, the beam spreads P3 and P4 are P3-P4=2λz/d.'' (10).

Here, λ is the wavelength of the ultrasound. At this time, the echo from the intersection area of the ultrasound beam that is received earliest is the first one.
This is the echo that propagated along the path A-Pl-8 in Figure 0(b), and the echo that is received the latest is A-P5- in the same figure.
This is an echo that followed the path P3-P2-P4-P6-B.

Therefore, the spread of the scattered wave Ts is Ts" c l A" P2 "B-A-P 1 "B), where the speed of sound is C.
Rikichi iP5・P3・P2・P4・P61= 2λ Z/
Cd −S i n θ, · (N). Here, for example, d = 16M, Z = 40
s, θ=20°, λ= 0.4 M1C= l, 5
If rta/μS is Ta"; 3.9μseC. Therefore, in this case, the cutoff frequency is 25kHz (f c (855kHz). Also, depending on the depth of the intersection, the aperture width, the deflection angle, and the wavelength, By changing this cutoff frequency or selecting and using several low-pass filters with different cutoff frequencies, a sufficient effect can be obtained in removing high-frequency noise components that cause peak position misidentification. Also, at this time, this frequency is too low for general 8-mode image reproduction, and in systems where the B-mode image is also obtained from the same received echo, it is necessary to provide a separate filter for the B-mode and pass it through. Use the one you made.

Further, although an analog filter is used in this embodiment, it is of course possible to use a digital filter without any problem.

A method using a digital filter will be explained. −
As an example, one statistical processing method for detecting time differences between signals whose waveforms are known will be explained using a method using a cross-correlation function.

In this method, a cross-correlation function between a reference waveform signal and an obtained echo signal is obtained, and the propagation time is detected from the peak occurrence time. As this reference waveform signal, a signal subjected to experimental answer averaging processing may be used, or approximately a Gaussian waveform, a triangular waveform, a sine wave, or a rectangular waveform may be used.

The reference waveform signal is g(t), and the obtained echo waveform is f(
t), the cross-correlation h(τ) is obtained as follows.

h (τ) = fQ (t) f (at t-) dt... (1
2) Obtain the propagation time difference from the peak occurrence time difference τ of this f(τ). If the reference waveform signal is a signal obtained by experiment,
The reference signal width is determined, but when using an approximate waveform, 0, 3 Ts < T (10
By setting Ts, a sufficient fluctuation suppression effect can be expected.

Also, digital filter processing can be performed before or after addition processing, but by performing it on the signal after addition processing,
It is possible to reduce the number of data.

As an example of an approximate reference waveform signal, a case of a rectangular reference waveform signal is shown in FIG. As shown in FIG. 6(a), a data window W with a time width T is set, and the integral value of the data within this data window W is taken as the data at the center time tc of the window. The process is repeated while changing the position, and the result shown in Figure 6 (
Obtain time-averaged data as shown in b).

The peak of this time-averaged data is detected, and the propagation time is determined from its time position. Naturally, a Gaussian waveform or a triangular waveform can be used for this reference waveform signal. In that case, weighting is performed during integration within the window.

In addition, in the ultrasonic wave transmission and reception in the cross-mode sound velocity measurement described above, this device measures the moving 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 eight points. As shown in FIG. 2, the moving distances of the center positions of the transducer group belonging to point 0 and the transducer group belonging to point 0 in the transducer arrangement direction are the same distance Δy.

Further, the deflection angle θ of the ultrasonic beam is set to θ0 in both cases, and is made equal.

Therefore, as a result, point pH and point P12 are in a positional relationship that is symmetrical about a line that passes through point Poo and is perpendicular to the ultrasound transmission/reception wave surface of probe 1, and the distance between them is Δy becomes.

Here, point Poo, point P110 and point P12 are ultrasound reflection points in the internal tissue of the subject, but at the same time A of probe 1
It means the intersection of the ultrasonic transmission/reception directional directions by the transducer groups belonging to the point, point 8, point 0, and point D, respectively.

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

Δt= ((tl-t2)+(t3-t4))
/2=((tl+t3)/2)-((t2+t4)/2
)...<13) Δt obtained by executing the calculation of equation (13) is the point pH
→This is the estimated value of the propagation time of the ultrasonic wave propagating along the path between point Poo and point P12.

Therefore, the calculation circuit 18 changes the point Pz to the point Po.

→Average sound speed CA of ultrasonic waves propagating along the path between points P12
is calculated using the following formula.

CA=(Δy-co)/(Δt-3inθ0)...(
14) The average sound velocity calculated by this equation (14) is calculated locally in the internal tissue of the subject (in this case, point p11.Poo).

represents the speed of sound in the region (including PI3).

In this way, it is possible to calculate the sound velocity locally in the internal tissue of the subject from the reflected components of the ultrasound waves at the 23 points Pit, POO, and PI. 13, by appropriately switching and changing the intersection position of the directional directions in the transmission and reception of ultrasound, it is possible to determine the sound velocity at multiple locations in the tissue within the body of the subject without changing the deflection angle θ.

FIG. 3 is a diagram showing a region where the local sound velocity can be measured by switching the vibrator. Generally, the delay time that determines the pointing direction is obtained by a delay element, but this delay element has a limited range of delay times that can be set. Therefore,
Since the above-mentioned intersection point is specified, the marker generator 29 is configured to output a beam bus passing through this possible intersection position as a marker, and when a measurement route is set, the beam bus on this measurement route is Select a bus as a marker and output it.

In the figure, 31 is the measurable region of local sound velocity, and this region 3
The symbol Poo in 1, ~P7 I is added and indicated with "・"
is the intersection of the ultrasonic transmission and reception directional directions.

In this case, as described above (Poo, Pls.

PI3), (P+ 1.P21, P22).

(P+2.P22.P23>, (P21.P31゜P3
2), (P22.P32.P33).

(P23, P33, P34), ..., in line with the abnormality to be measured, the first intersection and the point that passes through this first intersection and is perpendicular to the ultrasonic wave transmission/reception plane of the probe 1. The second position is located in a line-symmetrical relationship with the line as the axis. Select a combination of three reflection points at the third intersection, perform the above measurements on the filtered reflected waves using the ultrasonic beam that passes through the above-mentioned routes at the three intersections, and calculate the equation (14). By calculating the average sound speed, it is possible to determine the distribution of the average sound speed at a desired location within the measurable region 31.

The desired local sound speed value calculated by the calculation circuit 18 can also be displayed as a sound speed distribution on the nice play 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 averaging) is performed using the following equation.

C=(1/N)ΣC...(15) Here, C is the unsampled average sound speed information, and N is the number of combinations of intersection points used to calculate the local sound speed, which is 3 in the case of this example. be.

Also, unsample averaging can be performed as follows.

That is, from each combination of three intersection points, the measured propagation time is set as Δti and according to equation (16), the ultrasonic propagation time is first unsampled and averaged, and the average result is used to calculate
Calculate the equation (17) to obtain the sound speed value C.

Δ仝=<1yN>U (Δt〜i), (16
)l s=+1 (17) The unsampled average result of the sound speed values thus obtained is displayed on the display 17 as shown in FIG.

Also, if you want to see the A mode 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 criminal control method 2
5A immediately after collecting data on all the ultrasonic beam transmission and reception paths to be subjected to measurement to obtain the ultrasonic propagation velocity information,
Control is performed to sequentially freeze the obtained ultrasound tomographic images. Then, the measured sound speed values for each route are obtained and displayed on the display 17, and the average value is plotted and displayed. Further, an A-mode image is generated from the data stored in the memory 22, and an A-mode image using the average value on the same route is obtained by the calculation circuit 18,
As shown in FIG.
The image is displayed frozen in a predetermined position and in a predetermined format.

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

When the freeze command is released, the measurement display returns to the normal mode described above, and the mode image display and the sound speed measurement data are sequentially updated in real time.

In the embodiment described above, in the normal mode, cross-mode sound velocity measurement for 1 loop is inserted between scanning of 8-mode images, and only the B-mode image and sound velocity measurement values are updated. As a result, the B-mode image can be displayed in real time, and the sound velocity values at multiple locations in the internal tissue of the subject can be successively measured and updated for display. In addition, for sound speed measurement, the ultrasonic beam reception signal for sound speed measurement is filtered through a low-pass flow filter, high frequency component noise is removed, and multiple samples are averaged and the peak field is detected from this. Since the time position is detected and used to calculate the sound speed value, the number of samples can be reduced due to high frequency noise removal effect through filtering processing, and therefore, it is possible to measure the sound speed with high precision while maintaining real-time performance. becomes possible.

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 can be implemented with appropriate modifications within the scope of the gist. be.

〔Effect of the invention〕

As described above, according to the present invention, in an ultrasonic diagnostic apparatus having a cross-mode sound velocity measurement function, it is possible to detect the propagation time with high accuracy and high stability from a small amount of sample data including fluctuations such as speckles, and moreover, It is possible to provide an ultrasonic diagnostic apparatus with a cross-mode sound velocity measurement function that can be realized with a small amount of sample data, so that real-time performance is not impaired, and the reliability and performance can be dramatically improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention;
FIG. 2 is a diagram for explaining the present invention in detail, FIG. 3 is a diagram for explaining the measurement point setting area in the probe of this device, and FIG. 4 is a diagram showing an example of the display of this device. , Fig. 5 is a diagram for explaining in detail the present invention in which filtering processed waveforms of cross-mode sound velocity measurement data are added and averaged to suppress the influence of fluctuations, and Fig. 6 is an overview of the digital filtering processing. Figure for, No. 7
The figure is a diagram for explaining the principle of cross-mode sound velocity measurement, Figure 8 is a block diagram showing the configuration of a conventional ultrasonic diagnostic device that performs cross-mode sound velocity measurement, and Figures 9 to 11 are 12 is a diagram showing an example of a display of a conventional device. FIGS. 13 and 14 are diagrams illustrating the relationship between speckle reduction and time position measurement error caused by the conventional device. It is. 1... Probe, 13... Multiplexer, 14.
...Balsa, 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 oscillator, 22...
Memory, 23... Processing circuit, 24... Waveform analysis circuit, 25A... System control means, 26... Changeover switch, marker generator, 30... Digital scan converter, 31a, to 31c ...Low pass filter, 32...Selection switch, TI, ~T128.
...Ultrasonic vibration element. Applicant's agent Patent attorney Takehiko Suzue Figure 2 Figure 3': l! :1 Figure 4 Figure 6 Figure 11 Figure 12 + t ” t(a); + Figure 13 Figure 14

Claims (1)

[Claims] Using a probe configured by arranging a plurality of ultrasonic transducer elements in parallel, a predetermined number of adjacent ultrasonic transducer elements of this probe are grouped together, and a target region of the subject is
In order to transmit and receive ultrasound beams through multiple ultrasound transmission and reception paths, a group of ultrasound transducer elements for transmitting and receiving different ultrasound beams are used to transmit and receive ultrasound beams to the target area. In an ultrasonic diagnostic apparatus equipped with a sound speed measurement function, the ultrasonic propagation velocity information of the target area is obtained by detecting reflected waves from the source and measuring the time required from transmission to reception of the waves, and is used for diagnosis. An ultrasonic diagnostic apparatus that is used to measure the speed of sound and is provided with a filter that extracts a low frequency component of a received signal of the ultrasonic beam, and uses the extracted received signal to measure the speed of sound.