JPS62122639A - 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 this 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. 5 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 move θ into the body from one end A of the ultrasound receiving surface 2 that is in contact with the body surface (not shown).
Fires ultrasonic pulses in the direction.

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 depending on the direction of the transmitted ultrasonic beam and the position of the transducer in the beam. , 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 one pitch at a time, the position of the generated ultrasonic beam shifts, so 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 (echo),
The echo that arrives at the probe 1 following the delivery route 5 is received not by the transducer group that sent it, but by the transducer group at the incident position of the echo that arrived (the transducer group on the right @B of the probe 1). let

Since the distance y between A and B is known, if the propagation time t of the ultrasound propagating along the path 4.5 is measured, the sound velocity C in the liver tissue is C, -V/ (t - sin θ'' ) −(1
) can be obtained.

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, and the probe 1 is configured by linearly arranging transducers TI to T128 of, for example, 128 elements for transmitting and receiving ultrasonic waves. Transducer TI
, ~T128 juxtaposed surfaces become the ultrasonic wave transmitting/receiving surface 2 of the port 11 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, 16
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 for conversion, 21 is an oscillator for generating a clock signal for sequentially updating addresses for the memory in order to sample and store the rate pulse signal for driving the pulser and the echo from the target subject part, 22 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). This system control means 2
5 controls the operation of the multiplexer 13, sets the delay time of the transmission delay circuit 15 and reception delay circuit 16, controls writing and reading of the memory 22, and controls the operation of the calculation circuit 18, according to a predetermined program. It governs the

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 transducer TI,
~T128 is, for example, the element width a of each vibrator is 0.67j
11, this is the pitch d −0,7 between the element centers.
128 elements are arranged linearly at intervals of 2 m. 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 a reference clock of, for example, 10 M) Iz, and also divides the frequency of this to convert it into a 4 klb rate pulse and outputs it. This rate pulse is 32
32 pulsers 14 are driven through 32 transmission delay circuits 15. The pulsers 14 are circuits that generate pulses for ultrasonic excitation drive, and the outputs of these 32 pulsers 14 are sent to 128 transducers T11. ~T128, TI at the A end, ~T3
2 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 probe 1, and the ultrasonic waves output from the transducer elements are propagated into the living body.

Assuming that the speed of sound in living tissue is standardly Co -1530 [m/S], the delay time between adjacent elements τO z:o = (d/Co) ・To radiate an ultrasound beam in the θ0 direction s i nθo
-(2), and the transmission delay circuit 15 is set so that each element is driven with such a delay time difference.

That is, p[)1-0, PD2-τ01p[)3=
A delay time of 2τo, .=PD32=32τ0 is given.

If the sound speed in the living tissue is Go, 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 t nθo/Go from Snell's law.
- The value shown in (3) is obtained.

After emitting the ultrasonic pulse, the multiplexer 13 transmits the vibrating element T97. ~The ultrasonic reflected wave signals received at T128 are synthesized after receiving the same delay as in the case of transmission,
The signal is input to the receiving circuit 19. Here, the reception delay circuit 16
The delay time is RDl-31τo1RD2-30τo1
−”=, RD31=−τ0°RD32-0.

In this way, even if the ultrasonic beam transmitted in the 00 direction at the sonic speed Go has a sonic speed C in the living body and has directivity in the θ direction, the transducer element group T97. ~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 10M) lx 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 time of ultrasonic pulse emission. For example, 100n8
Accurately match spacing accuracy. Therefore, the address indicates the time at which data at that address was obtained (the elapsed time from the time when the ultrasonic pulse was emitted).

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 equation (3) into equation (1), the sound velocity C in the living body becomes C-VCo/(t-sinθo) ・”(4).Furthermore, substituting equation (2) into equation (4), c=F1 777...(4').y, d, τ
Since 0 is known, the propagation time t obtained by measurement
Using the calculation circuit 18, the above equation (4') is calculated to obtain the value of the sound speed C, and the value is output to the display 17.

FIG. 7 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, the earliest of the reflected waves mentioned above will arrive via the 21 points in Figure 8, and the one that will arrive the latest will arrive via the 12 points. Become something to do. 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 7(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. It will look like (C).

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 3.5MTo as the ultrasonic frequency, y-48
Assuming that the ultrasonic beam is focused near the intersection point P, the beam width (about 17% at the peak in transmission and reception) near the point P is about 21M.

At this time, the propagation time difference Δt between the one passing through 21 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 i. Since the measurement accuracy at time t2 of the peak value is considered to be 1/10 or less of Δt, it can be said that the sound velocity measurement error is 10 m/s or less.

The sound speed measured in this way is the path 4.5 in Figure 5.
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 is shown using FIG.

FIG. 9 is an explanatory diagram of a case where the ultrasonic wave transmitting/receiving surface 2 of the probe 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 an abnormal tissue (for example, a 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 the beam direction directions for both transmission and reception) is Pl, and the abnormal tissue 34 indicated by PO
The transmitting and receiving position of the ultrasonic beam is determined so that it comes to the boundary point of the part. At this time, the above measurement points pi, po with probe 1
The extension line position is O, and in the propagation path of the ultrasonic beam with 21 points as measurement points, the emission point of probe 1 is A, the 81 incidence point is 8 and 01, and 10 points are measurement points. The emission point in the propagation path of the ultrasonic beam is C and 01, the incident point is D and 01, and the extension line position of the measurement points p1 and pO on probe 1 is 0, and the propagation path passing through each of these points (A- +B, A-+O.

B-+0. C-+D, c-+o, D-+0) r propagation time t (AB), t (AO), t (BO), t(C
D), t(Co), and t(Do) are determined.

In addition, the round-trip ultrasonic propagation time between Pl and PO is 1°C,
A-) Ultrasonic propagation time between PO and APO.

The ultrasonic propagation time between PO→B is POB, the ultrasonic propagation time between PO→O is POO, the ultrasonic propagation time between C-+p1 is CPl, the ultrasonic propagation time between P1→DP1 is PI
D, let Plo be the ultrasonic propagation time between P1 and O, and use these to calculate t(AB).

t (AO), t (Bob, t (CD).

Calculate t (Co) and t (Do). That is, t
(AB)=APO+POB t (AO)=APO+ (t/2/2 >+
P1 0t (BO)=BPO+(tn/2) 10P
10t (CD)=CP1 +PI Dt (
Co)=CP1 +pi Ot (Do)=DP
I + P1 0... (5) From this, 1°C can be found using the following formula.

tg=[(t(AO>+t(BO)-t(AB>)-(
t (Co)+t (Do)-t (CD))]...
(C6 Therefore, the distance between Pl and PO is x2, and the average sound speed is 0℃
, where the distance between AB is yO and the distance between CD is yl, Cβ=2Xj2/l/! .

= (yO-yl)/(tn-tanθ)...(
7) XI-(yO-yl)/2tanθ・<8
), the local sound velocity C° can be found. As the value of θ, using the average sound velocity C of the normal liver part, θ-8i is calculated from equation (3).
n゛1 ((C/Co)-sinθ0)... (9
) as an approximate 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. 9, 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, and are used for diagnosis as well as for photographing or 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
, O, For the 0 point, the propagation path (A-+B, A→O, B→
0, C→D, C→○.

The propagation time in a total of six propagation paths (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, the thickness of the abdominal 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 the sound waves and the measurement results on each route. Due to factors such as the influence of biological motion due to timing deviations, each measurement value contains an error. 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 method, especially from B to A. , due to the asymmetric measurement in which measurements on the path from D to C are missing, the average is statistically non-uniform, so the problem remains that the above error cannot be strictly reduced.

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 uses the reflection point (measurement point) Pl and Pl2 at the upper boundary, the reflection point (measurement point) at the lower boundary), and the localization of the abnormal part included in PDII. When measuring the speed of sound, the ultrasonic beam transmission and reception path is (1
1A-+Pn-4B.

(2) A-+Pt L-+c1 (3) 84pHo
→ A, (4) P12 → D take 4 routes.

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, it transmits a wave from position A, receives what is reflected at Poo at position 8, then transmits it from position A, and receives the wave reflected at Poo.
The wave reflected at l is received at position C, then transmitted from position B, the wave reflected at PH1+ is received at position A, then transmitted from position B, and the wave reflected at Pl2 is transmitted at position C. By switching between transmitting and receiving, the measurement path is made symmetrical, and moreover, 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 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 a B-mode image of the subject's region of interest measured in real time; 41
indicates the route of the set beam path for the cross-mode sound velocity measurement in this region of interest, and 42 indicates the real-time A mode for each beam path route obtained by the cross-ψ mode sound velocity measurement. statue, 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 the sound velocity value 33 indicates the sound velocity value of the route (1) above among these routes, Vl, and the sound velocity value of the route (2) above. ) is the sound velocity value of the route of the route V2
, the sound speed value of the route (3) above is numerically displayed as V3, and the sound speed value of the route (4) above is numerically displayed as ■4.

Note that ■ is the average sound speed value of these four routes. Further, the average sound speed value change diagram 44 shows the time change of this average sound speed value. Also, A-moat image 42ha JL, -
(1), (3), and (7) are also displayed with (7) as 81 and B3, and the roots (21 and (4)) as 82 and 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, it is necessary to perform complex selection of transducers in which groups of transducers are used for transmission and reception at different positions, and delay circuits for transmission and reception are also required. Since the settable delay time is limited to a predetermined range at predetermined step increments, the depth of each reflection point as shown in Figure 2 is determined by the possible delay time of the delay circuit due to hardware and cost considerations. The number of elements in each transducer group for transmission and reception is always a constant number even if the depth is different due to the simplicity of the hardware.

However, since the ultrasonic beam is formed using the electronic scanning method, the following disadvantages arise.

That is, the aperture width, which is the width of the vibrator group to be excited, is closely related to the focal size and depth of the transmitted and received ultrasonic beam, and the beam width.

For example, if the aperture width is the width of the aperture and the wavelength of the ultrasonic wave is λ, then in the case of an electronic scanning method that uses the interference of the ultrasonic waves emitted from each transducer, the ultrasonic beam will become ultrasonic at a depth of D2/4λ or more. The beam tends to diverge. Therefore, the resolution becomes extremely poor at locations deeper than the focal point. Therefore, the focal length is adjusted to the desired depth by controlling the delay time of each transducer in the transducer group used, but as mentioned above, the delay time that can be set for the delay circuit is fixed. , the degrees of freedom are limited.

Therefore, when the aperture width is fixed, the aperture width must be made large to some extent in order to ensure the resolution at the deepest settable position, taking into account the divergence based on the above-mentioned relationship D2/4λ.

For this reason, if the focal point is set at a shallow position, the focusing at the focal position will be large, and if the focal position is slightly deviated, the beam width will suddenly become thicker, so unless the reflection point coincides with the focal position, , the accuracy of cross-mode sound velocity measurement becomes worse. As already mentioned, the delay time that the delay circuit can take is stepwise and of limited types, so it is rare for the desired reflection point to be successfully focused.

Therefore, there is a drawback that the accuracy of sound velocity measurement is not sufficient.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and its purpose is to provide an ultrasonic diagnostic apparatus having a cross-mode sound velocity measurement function without changing the settable delay time of the delay circuit. , it is possible to maintain resolution in the depth direction (distance resolution) and resolution in the direction perpendicular to the beam direction (azimuthal resolution) at shallow positions, thereby improving cross-mode sound velocity measurement accuracy. An object of the present invention is to provide an ultrasonic diagnostic device with a cross-mode sound velocity measurement function.

[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 transducer elements in parallel, groups a predetermined number of adjacent ultrasonic transducer elements of the probe, and selects Ultrasonic beams are transmitted and received using a group of ultrasonic transducer elements to obtain ultrasonic tomographic images, which are displayed on a display. In order to transmit and receive ultrasound beams, a group of ultrasonic vibrating elements for transmitting and receiving different ultrasound beams are used to transmit and receive ultrasound, detect reflected waves from the target area, and transmit the waves. In an ultrasonic diagnostic device that obtains information on the ultrasonic propagation velocity of the target area by measuring the time required from the point to the reception of the wave, and displays this information on the display for diagnosis, the aperture width is adjusted according to the selected focal position. The smaller the number of oscillators in the above group is selected, the more the shallow focus position is set in order to vary the aperture = 2
6- Features include a variable width selection function, a control means for selecting and controlling the vibrator used for transmission and reception, and the number of constituent elements of the vibration group used for transmission and reception can be varied according to the selected focal position. shall be.

In such a configuration, when a focus position for cross-mode sound velocity measurement is selected, the control means selects a cross-mode sound velocity measurement transmission/reception position that groups a predetermined number of vibration elements according to the selected focus position. The transmitting and receiving transducer groups are selected and used for ultrasonic transmission and reception. At this time,
The number of vibrating elements forming a group increases as the selected focus position becomes shallower.
The number of oscillators in the group is selected to be small. As a result, when a shallow position is focused, the aperture width of the transducer becomes narrower, the ultrasonic beam becomes narrower, and the focusing at the focal position becomes smaller. Therefore, unlike when a thick ultrasonic beam is used in the past, the beam width does not suddenly increase when the focal position is slightly deviated, so even if the reflection point does not match the focal position, the distance And azimuth resolution can be ensured sufficiently over a wide range. Furthermore, since the aperture width is made sufficiently wide at a deep focal position, it is possible to prevent resolution degradation due to dispersion. Therefore, even if the delay time that the delay circuit can take is stepwise and of limited types, and the focal position cannot be freely selected, the cross-mode sound velocity measurement accuracy is dramatically improved.

By making the aperture width variable according to the selected focal position, ultrasonic diagnostic equipment with a cross-mode sound velocity measurement function can be used at shallow positions without changing the settable delay time of the delay circuit. It becomes possible to maintain the resolution in the depth direction (distance resolution) and the resolution in the direction orthogonal to the beam direction (azimuth resolution), and therefore it becomes possible to improve the cross-mode sound speed measurement accuracy.

[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 pulser, 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 symbols as in FIG. 5 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. ,2
7 is a receiving circuit on the ultrasonic device side, which amplifies the received signal,
It performs wave detection, logarithmic conversion, etc. 28 is an A/D converter, which converts the output of the receiving circuit 27 into a digital signal. Reference numeral 29 denotes a marker generator, which generates image data for displaying the measurement route (beam path route) of the cross-mode sound speed measurement. 30 is a digital scan converter, which converts the frame
It has a memory and sequentially updates and stores the digital data output from the A/D converter 28 at the address corresponding to the beam position where the data was collected, and reads out data in accordance with the scanning timing of the display 17. conduct,
Thus, by interposing this frame memory, the difference between the acquisition timing of the ultrasound image and the display timing on the display 17 can be converted without any problem. Further, the output of the marker generator 29 is written on 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.

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. Then, an image is displayed based on the image data 30 on the video RAM and the output of the digital ◆ scan converter 30.

This device is basically the same as the one explained in the prior art with regard to cross-mode sound velocity measurement, but in contrast to 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 1G, the writing and reading control of the memory 22, the operation control of the calculation circuit 18, the switching control of the changeover switch 26, and the marker generator. 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. Calculates the measurements and displays the results, and calculates and plots the average sound speed of the entire beam path.

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 images with measurement data in the beam path, average A
A mode image display, an average sound speed change diagram or a local sound speed change diagram of one selected beam path are displayed.

Regarding the cross mode sound velocity 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 velocity of the abnormal part included in the reflection points (measurement points) Pll and PI3 at the upper boundary and the reflection point (measurement point) Pan at the lower boundary. The ultrasonic beam transmission/reception path is changed to A-+Po.
a 4B, A-) PllLC, B-) Po rr →
Try to take four routes: A, B → Pt 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 P++o and received at position B, then transmitted from position A, and the wave reflected at P++o is received at position B.
The wave reflected by L is received at position C, then transmitted from position 8, the wave reflected by Pan is received at position A, and then the wave is transmitted from position 8.
By switching the transmission and reception such that the wave is transmitted from the ultrasonic beam position and the wave reflected by PI3 is received at the D position, the measurement path is symmetrical, and the directional direction of the ultrasonic beam in the transmission and reception direction is changed. are made to be the same angle θ. Furthermore, by making the measurement route symmetrical, it is possible to avoid a statistically unrestricted average, thereby reducing errors.

Furthermore, the system control device 25A transmits data according to the depth of the selected reflection point when measuring cross mode sound velocity.
The number of transducers in each group for reception is varied and selectively connected.

This depends on the depth of the set observation point, that is, the depth of the selected reflection point, and since there is no need to consider the dispersion of the beam at a deep position at a shallow position, it can be used over a wide range centered around the focal point. In order to improve the resolution of the beam, the number of excited oscillators is reduced and the aperture width, which is the oscillator distribution width used for transmission and reception, is narrowed. In addition, if the selected reflection point is located at a deep position, the measurement target position is deep, so it is necessary to take into account beam dispersion near this area, so that beam dispersion near this area does not occur. In order to make the beam thicker, we increase the number of excited oscillators and widen the aperture width. Note that this opening width is determined in advance for each settable depth. As a result, the resolution at each measurement position is improved to ensure sound speed measurement accuracy, and this is the most distinctive feature of the present device.

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 B1, 82, B3, and B4 as shown in Figure 2, and each reflection point is determined by the operator by referring to the B-mode ultrasound image. Each reflection point shall be set in advance at an optimal depth close to the target area. And B
The changeover switch 26 is temporarily switched from the terminal B side to the X side at a predetermined timing between the ultrasonic electronic scanning modes, and sound velocity measurement is performed.

To explain specifically, first, the system control means 2
The selector switch 26 is switched to the terminal B side under the control of the delay circuit 15.5A, and the multiplexer 13 is selected for linear electronic scanning, and the delay circuit 15.
Delay times 16 for linear electronic scanning are set, and ultrasonic waves are transmitted and received from the transducer group selected by the multiplexer 13 using these delay times. The combined 8 power of this received signal is amplified and detected by the receiving circuit 27, and 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. While sequentially shifting the scan position, these ultrasonic scans are sequentially processed to form an ultrasonic B-mode image in the digital scan converter 30. In addition, a beam bus marker for cross mode sound velocity measurement set by the marker generator 29 is output,
The marker is stored in the frame memory of digital scan converter 30 at a position corresponding to the cross-mode sound velocity measurement position. The frame of the digital scan converter 30 thus formed
The image data on the memory is read out in accordance with the scan of the display 17, 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 begins with B1
Do this route.

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 equal to τo−(d/Co)sinθ0 (formula (2) above).
The relationship is set as follows. Then, under the control of the system control means 25A, a predetermined number of transmitting vibration elements belonging to the point A of the probe 1 and corresponding to the reflection point setting depth are controlled by the switching operation of the multiplexer 13. It is connected to the output end of the balsa 14.

For example, if the predetermined number of transmitting transducer elements TT (Xi, j) belonging to point A of the probe 1 at this time is 32, the transducer group TI, ~T32 and the output end of the balsa 14 are connected. be done.

Further, a rate pulse is generated by the clock oscillator 21, and this is input to the balsa 14 via the transmission delay circuit 15. Then, from the balsa 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 balsa 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, 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 transducer elements TR (Xi.

j) is connected to the input terminal of the corresponding delay circuit 16 by the switching operation of the multiplexer 13.

Here, since the number of transmitting transducer elements TT (Xi, j) is 32, there are 32 transducer groups T belonging to point B of probe 1.
97. ~T128 and the input terminal of the receiving delay circuit 16 are connected. As a result, the ultrasonic beam transmitted toward the subject from the transducer group belonging to point A of the probe 1 is received by the reflection valve at point Poo by the transducer group belonging to point B of the probe 1. The echo is transmitted to the receiving delay circuit 16.
After giving the same time difference as in the case of transmission, the signals are 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 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 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 multiple times by the transducer groups belonging to each of the points A and B of the probe 1,
By the action of the processing circuit 23, the received echoes are averaged.

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 the point B is changed to the group of transducers belonging to the zero point of the probe 1. Oscillator group (in this case, the previous 81
Since the position is shallower than the reflection point of the route, the predetermined number for both transmission and reception is smaller than this) and the input terminal of the reception delay circuit 16 corresponding to each is connected. A predetermined number of vibrator groups are each connected to a corresponding balsa 14. Then, the reflected component at point P11 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 is then used to measure the time t2 until delivery from the transmission of the ultrasonic wave on the route B2.

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 In the example, a transmitting transducer group T97.32 elements). ~T128 and their corresponding balsa 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
An ultrasonic wave is transmitted from the transducer group belonging to point B of the probe 1, and a reflected component of the transmitted ultrasonic wave at point Poo is 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 4l-t3 from ultrasonic wave transmission on the route B3 to delivery.

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, a predetermined number of transducer groups belonging to point D of probe 1 and corresponding to the above reflection point setting depth on the route B4 (in this case Since the position is shallower than the reflection point of the previous 83 routes, the predetermined number is smaller than this for both transmission and reception) and the input terminal of the reception delay circuit 16 corresponding to each is connected, and also to point B of the probe 1. A predetermined number of vibrator groups that belong to the group are connected to corresponding balsers 14, respectively. Then, the transducer group and the input terminal of the receiving delay circuit 18 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 received echo is transmitted to the receiving delay circuit 1.
6, the signals are combined 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 2G 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, 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 peak, and the information of the address where the data is stored is converted into time information. As calculation circuit 1
Sent to 8th. Based on this, the calculation circuit 18 calculates 81. B2, 83° The time from ultrasonic wave transmission to the above peak for each route of B4 is t1, t2. t3. t
4 is calculated. After that, the sound speed value V1 for each route. V
2.

V3, V4 and average sound velocity value V in all beam paths
is 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.
Beam path marker indicating the route of the beam path set for mode sound velocity measurement, 53 is a frozen A mode image for each beam path 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 path and 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 path and route. The beam path marker 52 indicates the routes (1) to (4) above,
Also, the sound speed value 54 is the sound speed value of the route (1) above among these routes, vl, the sound speed value of the route (2) above, ■2, the sound speed value of the route (31), above (31), The sound speed value of the route in (4) above 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 of each route. In addition, the average sound speed value change diagram 55 shows the time change of this average sound speed value.

Also, the A mode images 53 are 81 for roots (1) and (3), 82 for roots (2) and 4) as B3, and 82 for roots (2) and 4).
．． It is displayed as 84.

In addition, in the ultrasonic wave transmission and reception in the cross-mode sound velocity measurement described above, this device detects 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 moving distance of the center position of the transducer group belonging to point A and the transducer group belonging to point D, respectively. The movement distance of the center position in the transducer arrangement direction of the transducer group belonging to point 0 and the transducer group belonging to point 0 is the same distance Δy as shown in diagram M2.

Further, the deflection angle θ of the ultrasonic beam is set to B0 and is made equal in both cases.

Therefore, as a result, the points P1s and P12 are in a positional relationship that is symmetrical about a line that passes through the point Poo and is perpendicular to the ultrasound transmission/reception wave surface of the probe 1, and the distance between them is Δy becomes.

Here, the point P o o r point Pt t and the point P12 are the ultrasonic reflection points in the internal tissue of the subject, but at the same time, the transducer groups belonging to the points A, B, 0, and D of the probe 1, respectively. This means the intersection of the ultrasound transmission and reception directional directions.

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)...(10) Δt obtained by executing the calculation of equation (10) becomes the estimated propagation time value of the ultrasonic wave propagating along the path between point pH→point Poo→point P12.

Therefore, the calculation circuit 18 changes the point P11 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-5inθ0)...(
11) The average sound velocity calculated by this equation (11) 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 PI2).

In this way, the sound velocity in the local tissues of the subject's body can be suppressed from the reflected components of ultrasound at 23 points of pH, POO, and PI, so the transducer used for transmitting and receiving ultrasound waves is By appropriately switching the multiplexer 13 and changing the intersection position of the directional directions in the transmission and reception of ultrasound, it is possible to determine the sound speed at multiple locations in the internal tissue 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 path passing through this possible intersection position as a marker, and when a measurement route is set, the beam path on this measurement route is Select and output the path as a marker.

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

In this case, (Poo, Pi 1
.

PI2), (PIt, P21, P22).

(PI2.P22.P2B), (P21, P31
.

P32), (P22. P32. Pyo 3
).

(P23 , P33 , P34 ),... Like,
In line with the abnormality to be measured, a second point of intersection and a second point of intersection that is symmetrical with respect to a line that passes through the first point of intersection and is perpendicular to the ultrasound transmission/reception wave surface of the probe 1. ．． Select a combination of three reflection points at the third intersection, and
The beam passes through the above-mentioned route at two intersection points, and the beam thickness is made different for each intersection position (i.e., at shallow positions, the aperture width is narrowed to create a thin beam, and at deep positions, the aperture width is The above measurement was carried out on the reflected waves using an ultrasonic beam (with a wide beam and a thick beam), and the results were as follows: (1
By determining the average sound speed by calculating the equation 1), it is possible to determine the distribution of the average sound speed at a desired local area 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 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 averaging) is performed using the following equation.

C-(1/N)ΣC...(12) 1:1 Here, C is the unsampled averaged sound speed information, and N is the number of combinations of intersection points used to calculate the local sound speed, in the case of this example. So it's 3.

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, the ultrasonic propagation time is first unsampled averaged using equation (13), and the average result is used to calculate (
14) Calculate the equation to obtain the sound speed value C...(14) The unsampled average result of the sound speed values thus obtained is displayed on the display 17 as shown in FIG.

Furthermore, if it is desired to view the A-mode image, a freeze command is given to the system control/control means 25A. 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 25A immediately freezes the obtained ultrasonic tomographic images one after another after collecting data on all the ultrasonic beam transmission and reception paths used for measurement to obtain the ultrasonic propagation velocity information. Control as follows. 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 of the same route is obtained by the calculation circuit 18, and each is given to the display 17 as shown in FIG. , 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 measurements for one ruple are inserted between scans of B-mode images, and only the B-mode images and sound velocity measurements 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, when you want to see the sound velocity measurements at a certain point in time, including the A-mode image, or the B-mode image, you can give a freeze command to freeze the B-mode image immediately after measuring the cross-mode sound velocity of the 4 routes. Since the sound velocity value is calculated and the A-mode image is generated, the B-mode image, A-mode image, and the sound velocity value at the same time phase can be displayed together. Furthermore, when measuring the cross-mode sound velocity, the system control means selects a predetermined number of vibration elements according to the selected focal position, based on the selection and setting of the focal position for the cross-mode sound velocity measurement previously performed. A group of transducers for transmitting and receiving at a cross-mode sound velocity measurement transmitting/receiving position is selected and used for ultrasonic transmitting and receiving. At this time, the shallower the selected focal position, the smaller the number of vibrating elements forming one group is selected. As a result, when a shallow position is focused, the aperture width of the transducer becomes narrower, the ultrasonic beam becomes narrower, and the focusing at the focal position becomes smaller. Therefore, unlike when using a thick ultrasonic beam as in the past, the beam width does not suddenly become wider when the focal position is slightly deviated, so even if the reflection point does not match the focal position, the beam width can be and azimuth resolution can be ensured sufficiently over a wide range. In addition, since the aperture width is made sufficiently wide at a deep focal position, it is possible to prevent a decrease in resolution due to beam dispersion.Therefore, the delay time that the delay circuit can take is in steps and is limited in type, so the focal position can be freely adjusted. Even if it cannot be selected, cross-mode sound velocity measurement will be dramatically improved. As a result, an ultrasonic diagnostic apparatus can obtain a comprehensive ultrasonic diagnostic image without time phase shift and including highly reliable sound velocity information that is extremely useful for diagnosis.

In addition, this device performs real-time observation and freezes as necessary to provide sound velocity information that reflects macroscopic changes in a certain part of the test resting place 53, for example, the entire liver, and the sound velocity information measurement route. Comprehensive information, including A-mode images, etc., can be observed in a single image, making it extremely useful for diagnosing organs such as the liver, whose flesh tissue is homogeneous when it is in its normal state. be.

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 thereof. be.

(Effects 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 perform measurement in the depth direction at a shallow position without changing the settable delay time of the delay circuit. It is possible to maintain resolution (distance resolution) and resolution in the direction orthogonal to the beam direction (azimuthal resolution), and therefore,
It is possible to provide an ultrasonic diagnostic apparatus with a cross-mode sound velocity measurement function, which has features such as being able to improve cross-mode sound velocity measurement accuracy.

[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 the principle of cross-mode sound velocity measurement, FIG. 6 is a block diagram showing the configuration of a conventional ultrasonic diagnostic apparatus that performs cross-mode sound velocity measurement, and FIG. 7 is a diagram for explaining the principle of cross-mode sound velocity measurement. 9 is a diagram for explaining its operation, and FIG. 10 is a diagram showing an example of a display of a conventional device. 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, TI, ~T128 ...Ultrasonic vibration element. Figure 2 Figure 3 Figure 4 Figure 5 Figure 8 Figure 9 Figure 10

Claims (1)

[Claims] Using a probe configured by arranging multiple ultrasonic vibrating elements in parallel, a predetermined number of adjacent ultrasonic vibrating elements of this probe are set as one group, and ultrasonic waves are generated using the selected group of ultrasonic vibrating elements. The beam is transmitted and received to obtain an ultrasonic tomographic image, which is displayed on a display, and the ultrasound beam is transmitted and received through multiple ultrasound transmission and reception paths to the target area of the subject. Using a group of ultrasonic vibrating elements for transmitting and receiving ultrasonic beams, transmit and receive ultrasonic waves, detect reflected waves from the target area, and measure the time required from transmitting the waves to receiving the waves. In an ultrasonic diagnostic apparatus that obtains ultrasonic propagation velocity information of the target area and displays it on the display for diagnosis, a shallow focal position setting time is used to vary the aperture width according to the selected focal position. , which has a variable aperture width selection function for selecting a smaller number of transducers in the group, and includes control means for selecting and controlling the transducers used for transmission and reception, and is a constituent element of the vibration group used for transmission and reception according to the selected focal position. An ultrasonic diagnostic device characterized in that the number is variable.