JPS62211046A - 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 (Objective of the Invention) (Industrial Field of Application) The present invention relates to an ultrasonic diagnostic device that diagnoses tissue within a subject using ultrasound, and particularly relates to an ultrasonic diagnostic device that diagnoses tissue within a subject using ultrasound. Ultrasonic diagnosis *i equipped with a sound velocity meter 1I11 and its display function for characterizing tissues by measuring them and providing them for diagnosis
It is related to AH.

(Prior Art) 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.

However, this means that it is possible to detect, for example, tumor lesions in organs, liver cirrhosis, etc. in a living body based on the ultrasonic propagation velocity. Measuring propagation 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 (al) and to examine 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 waves are transmitted into the body in the θ direction from one end A of the ultrasound receiving surface 2 that is in contact with the body surface (not shown). Fire a pulse.

As is well known, an electronic scanning type ultrasound device uses a probe consisting of an ultrasound transducer array in which multiple ultrasound transducers (hereinafter simply referred to as transducers) are arranged in parallel. A drive pulse is applied to each group of adjacent transducers with a predetermined delay time determined according to the direction of the transmitted ultrasound beam and the position of the imager in the beam. The ultrasonic waves from each excited vibrator propagate in a sword-like manner and interfere with each other, canceling each other out in some areas and reinforcing each other in others. As a result, an ultrasonic beam is obtained. Wave reception is generally performed using the 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. and 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 (echo),
The group of transducers used to transmit the echo that arrives at the probe 1 following the receiving path 5 is the group of transducers located at the input position tJA of the echo that has arrived (the group of transducers at the right end B of the probe 1). ) is received.

Since the distance y between A and 8 above is known, if the propagation time t of the ultrasonic waves propagating through paths 4 and 5 is shifted by 311 in total, the sound speed C in the liver tissue becomes CV/(t-sin θ) It can be obtained from (1).

This yAII 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 P inside the living body,
In order to obtain the speed of sound from the above equation (1), various measures are required. Therefore, a VA seal 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 constructed by linearly arranging, for example, 128 elements T1 to T128 for transmitting and receiving ultrasonic waves. Transducer TI
, ~T128 parallel crotch surface becomes 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 changeover switch; 15 is a transmission delay circuit for obtaining the amount of delay to be given to each of a group of stimulators to be excited;
4 is a balsa that generates pulses for ultrasonic excitation wtN motion, 1
G is a reception delay circuit for obtaining the echo delay amount necessary for aligning the time axis etc. according to the reception direction and element position for each of the group of image sensors used for reception, and 17 is a reception delay circuit for obtaining images and characters. A display used for displaying information, etc., 18 a calculation circuit, 19 a camera Tl 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 the resultant signal as a received signal; 20 converts the received signal into a digital signal; A/D to convert to
The converter 21 is a generator 22 that generates a clock signal for sequentially updating the address for the memory in order to sample and store the balsa drive pulse signal and the echo from the target part of the subject. A memory 23 for storing received signals 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. The processing circuit 24 examines the data indicating the 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 an analysis circuit. The calculation circuit 1B calculates the propagation time t from the time information obtained by the waveform analysis circuit 24, and also calculates the speed of sound at a plurality of localities in the internal tissue of the subject based on the obtained propagation time t. In addition, it has a function of spatially averaging and outputting these. This calculation result is then displayed on the display 17. 25 is a system control means, which is mainly configured with a CPLI (central processing unit; for example, a microprocessor). This system control means 25 follows a predetermined program.
Operation control of the multiplexer 13, setting of delay times of the transmission delay circuit 15 and reception delay circuit 1G, and writing to the memory 22, ii! It is in charge of protrusion control and operation control of the calculation circuit 18.

The transducers TI to T128 are excited when a voltage pulse is applied and emit ultrasonic pulses, and generate 21 pulses when the ultrasonic pulses are incident. For example, for the 128-element i-transducer TI, ~T128, the element width a of each transducer is set to 0.
67-, this is the pitch d-0.7 between the element centers.
128 elements are arranged linearly with two-way spacing. 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 reference clock for the IOMH 2, and also divides the frequency of this clock to convert it into a 4 kHz rate pulse and outputs the pulse. This rate pulse passes through 32 transmission delay circuits 15 and then passes through 32 transmission delay circuits 15.
balsa 14 is driven. The balsers 14 are circuits that generate pulses for ultrasonic excitation driving, and the outputs of these 32 balsers 14 are sent to the multiplexer 13, which is a switching circuit.
128 transducers T11. ~ Among T128, A
T11 at the end. - T32 are respectively inputted 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.

Standardly, the sound speed in living tissue is Co=1530 [m/S]
Then, in order to radiate the ultrasonic beam in the θ0 direction, i! between adjacent elements is required. ! Extended time τ0τ0-(d/Co)-8
inθ0−(2), and the transmission delay circuit 15 is set so that each element is driven with such a delay time difference.

That is, PDl -0%PD2-τo1p[)3-2
A delay time of τo, −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-5inθo/Co according to Snell's law.
'...The value shown in (3) is obtained.

After emitting the ms wave pulse, the multiplexer 13 transmits the vibration 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, reception delay circuit 1G
The delay times are RDI-31τ0, RD2-30τo,
...”・, R031-τo%RD32-0.

In this way, even if an ultrasonic beam transmitted in 80 directions at a sound speed of Go has a sound speed of C in a 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 sequentially updated 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 m.
It precisely matches the time from the time of emission of the sound wave pulse, with an accuracy of, for example, 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. When the above-mentioned equation (3) is substituted into equation (1), the sound speed C in the living body becomes C=JYCo/(t-sinθO)·(4). Furthermore, by substituting equation (2) into equation (4), c = (> 1
7 "Core...(4-).Since y, c+, and τ0 are known, the calculation circuit 18 calculates the above equation (4-) using the propagation time t obtained by measurement. The value of the sound speed C is determined and output to the display 11.

Figure 9 shows the time chart 1r - showing the method for measuring the t between
1, and the ultrasonic pulse is emitted at a time slightly delayed from the falling edge to of the rate pulse in (a). The pulse peak time is tl.

In this way, when there is a point reflector P at the intersection of the center of the transmitting beam and the receiving direction, the time t
The reflected wave having a peak at 2 is (q), 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 11 points in Figure 2, and the one that arrives the latest 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. It will look like (C).

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

Now, using 3.5Mce as the ultrasonic frequency, y-48m
5, and if the ultrasonic beam is focused near the intersection point P, the beam width near the point P (about 11% at the peak in transmission and reception) is about 21111. At this time,
The propagation vI (Jl difference Δ°C between the one passing through 11 points and the one passing through 12 points is about 4.5 μs.

In the case of C-Go, the ultrasound beam direction is θo
Assuming -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 4.5 in Figure 7.
This sound speed information is displayed on the display 17 together with the ultrasonic B mode (tomographic image) near the liver, which is the examination site in this case, and is used for diagnosis.

The above method is for finding the average sound speed in 33 areas 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 speed. The method will be shown using FIG.

FIG. 11 is an explanatory diagram when 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 11, and the propagation path set for sound velocity measurement is also displayed in 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 locally, that is, in this case, abnormal tissue within the liver 3
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 transmission and reception) is PI, 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
In the ultrasonic beam propagation path with 21 measurement points, the emission points of the probe 1 are A and B.

The incident points are 8 and 0, the emission points in the propagation path of the ultrasonic beam are C and 01, the incident points are D and 0, and the measurement points P1 and 10 are the measurement points. P
The extension line position of O is O, and the propagation path passing through each of these points (A-48, A-0, B→0.C-D, C→0.0→O
) at propagation time t(AB>, t(AO), t(BO
), t (CD).

Find t (Co) and t (Do).

In addition, the round-trip ultrasonic propagation time between PI and PO is t2,
APO is the ultrasonic propagation time between A110 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 CPI, the ultrasonic propagation time between P1→r)r'1 is Pl
D, the ultrasonic propagation time between Pi → 0 is Plo, and using these, t(AB).

(AO>, t (80), t (C
D).

Calculate t (Co) and t (Do). That is, t
(AB)=APO+POB t (AO)-APO+ (tj2/2)+P10t
(BO)-BPO+ (t Q/2 >+P1
0t (CD)-CPl +PI Dt (G
o>-CPl +P1 0 t (Do)-DPl +P1 0 (5) From this, t2 can be found using the following equation.

tR-[(t (AO)+t (BO)-t (AB)
) −(t (Go)+t (Do) −t (CD))] ...(6) Therefore, the distance between pi and po is X℃, and the average sound speed is 02
, the distance between AB is yO, and the distance between CD is yl, then 1-2) l/1j2 = (yO-yl)/(tffi-tanθ)...
(7) XQ= (yo −yl)/2tanθ...(8
) The local sound velocity C° can be found. As the value of θ, using the average sound speed C of the normal liver part, θ=SIn from equation (3)
'((C/Co) ・sinθ0)...(9) It may be determined using the following as an approximate expression. 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), which are displayed on the display together with the B-mode image and the display marker of the measured ultrasound propagation path. Or record it as a video and save it.

This type of sound speed measurement is called cross mode (or cross beam method) sound speed measurement, but in the case of the above-mentioned method, the propagation path (A → [3, A→O, B→O1C-ID, C→O, D-
0)(7)fft6')'7) The propagation time in the 11u path was measured 41 times to determine the local speed of sound.

By measuring three paths for one measurement point in this way, the ultrasonic beam is incident obliquely,
Accuracy is improved by reducing the influence of the abdominal wall (the influence of differences in the thickness of the body surface and subcutaneous tissue) caused by emitting light from an oblique direction.

However, the thickness of No. 19 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 timing on each route. Due to factors such as the influence of biological movement that causes misalignment, each measurement value contains an error. In the above method, this error is reduced by adding and averaging the measured values from various paths, but contrary to the original purpose, in the case of the above three path force method, especially from B to Strictly speaking, the above-mentioned error cannot be reduced because the asymmetric measurement in which measurements on the path from A and D to C are missing results in a statistically non-uniform average.

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 returning direction as a set, and thereby - per path, By performing detection measurements an even number of times (at least 2 times) with the transmitting and receiving directions reversed to ensure symmetrical measurements, and finding 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 making a statistically uniform average.

Specifically, as shown in Figure 2, this method is based on the localization of the abnormal part contained within the reflection points (measurement points) Pt+ and PI2 at the upper boundary and the reflection points (measurement points) Pa o at the lower boundary. When measuring the speed of sound, the ultrasonic beam transmission and reception path is (1
) A-+Pa 0-)B, (2J A-+Pt
t →C, (31B-+Po a-)A, (4)
It is designed to take four routes: P12→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 Pa o and received at position B, then transmitted from position A, and the wave reflected from Pa o is received at position B.
The wave reflected by il is received at position C, then transmitted from position 8, the wave reflected by Pea is received at position A, then transmitted from position B, and the wave reflected at PI3 is transmitted from position D. 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 incorporated into an ultrasonic diagnostic apparatus, and is usually displayed on a display together with ultrasonic III (for example, a B-mode image).

This situation is shown in FIG. In the figure, 4o is a B-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 the sound velocity value 33 indicates the sound velocity value of the route (1) above among these routes, vl, and (2) above. ) is the sound velocity value of the route of v2, and the above (
The sound speed Ill of the route No. 3 is numerically displayed as v3, and the sound speed value of the route (4) above is v4.

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. Moreover, the A-mode image 42 is the root (1
) and (3) are 81. As B3, Lou l-(2
) and (4) are displayed as 82 and B4.

In order to display such an image, the system 1llt
Under Ill 1ull of ll1 means, B mode elephant 4
0 is rewritten in real time, and in between, the cross-mode sound velocity measurements of the four routes mentioned above are performed, and the measurement results are displayed using the meter sieve circuit 18. The A-mode error is displayed using the echo obtained by cross-mode sound velocity measurement.

In other words, we collect 8-mode image data for several screens,
The B-mode fishing is displayed in real-time by sequentially updating the display and inserting cross-mode sound velocity measurement every time the data collection of the 8-mode image for several screens is completed.
The speed of sound is measured at a desired position while looking at the mode image.

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 is greatly affected by speckles caused by these scattered waves. It's changing. From this fluctuating measurement signal, as shown in Fig. 9(d),
The position of the peak value is determined and the above-mentioned propagation time t is measured, but the accuracy of the measurement result varies greatly depending on the position of the determined peak value. This directly affects the accuracy, stability, and reproducibility of the estimated sound speed. That is, when the peak position is detected using data with large speckles, a,
A peak value of data such as b is detected, leaving a problem of measurement instability in which different values are shown no matter how many times the same region is measured.

Therefore, in order to stabilize the signal with large fluctuations, the first
As shown in Figure 3, many sample signals @S1. ~3n is obtained and the average 3a is taken to reduce speckles.

Incidentally, the accuracy of sound velocity measurement is affected not only by speckle but also by the saturation of the received measurement signal. That is, as shown in FIG. 6, when determining the speed of sound using the peak of the measurement signal (echo) waveform, if the state is as shown by the solid line a in FIG. 6, the time point tp at which the peak of the waveform appears can be measured accurately, but as shown by the dashed-dotted line in the figure, if the level of the received signal is too high and reaches the saturation level vsat of the receiving circuit, the peak of the waveform will collapse. Therefore, the peak position is tp',
Accurate peak position cannot be measured.

Therefore, in order to avoid such problems, the surgeon needs to properly adjust the sensitivity of the receiving system in order to obtain data. Therefore, it is inefficient to measure the speed of sound by setting it by trial and error based on the operator's experience.

(Problem to be solved by the invention) In this way, when measuring the speed of sound in the conventional method, the level adjustment of the receiving system is carried out in order to suppress the saturation of the received signal, and the adjustment depends on the operator's experience. However, since it was not possible to precisely adjust the sound velocity to the optimum level, it took time to measure the sound velocity.

Furthermore, if this adjustment is insufficient, there will be a problem with the accuracy of the sound velocity measurement, making it impossible to ensure total accuracy.

Therefore, an object of the present invention is to provide an ultrasonic diagnostic apparatus having the ability to measure the sound velocity using the beam crossing method (cross mode), to be able to notify the operator when the received measurement signal is saturated. In addition, the cross mode allows for easy adjustment to the appropriate value and can be used for sound speed measurement, making it possible to measure sound speed efficiently and with high reliability no matter who makes the measurement. An object of the present invention is to provide an ultrasonic diagnostic device with a sound velocity measurement function.

[Structure of the invention]

(G; Means for solving the problem) In order to achieve the above object, the present invention uses a probe configured by arranging a plurality of ultrasonic vibration elements in parallel, and among the kQ wave prefectural elements of this probe, When a predetermined number of adjacent groups are grouped together, an ultrasound beam is transmitted to the target region of the subject along a transmission path in a predetermined direction. Ultrasonic waves are transmitted and received using a group of ultrasonic vibrating elements for transmitting and receiving different ultrasonic beams, respectively, in order to receive the ultrasonic beams using the receiving path of the ultrasonic beams. An ultrasonic diagnosis 1!i device equipped with a sound velocity measurement function that detects a peak and measures the time required from its transmission to peak reception to obtain ultrasound propagation velocity information of the target area and aid in diagnosis. , a receiving circuit with a variable amplification factor that detects and amplifies the ultrasonic received signal in the sound speed measurement mode for performing the sound 'a correction, and a receiving circuit that monitors the level of the output signal of this receiving circuit and detects when it is saturated. A saturation detector that detects saturation, a control means that notifies you when this saturation is detected and controls to display the A-mode image at that time, and an ultrasonic reception signal that detects saturation when measuring the speed of sound. The apparatus is constructed by providing analysis means for determining the peak position of the received signal from the target site and obtaining the ultrasonic propagation time based on the data obtained by averaging the received signals.

(Function) In such a configuration, when cross mode M speed measurement is started, the ultrasonic received signal after detection and amplification in the receiving circuit is checked by the saturation detector to see if it has not reached the saturation level, and saturation is detected. When this happens, the control means and waveform analysis means are notified of this. Then, the control means immediately informs the operator of the saturation by displaying text on the display device, or by using a buzzer or lamp, and the display device displays the ultrasonic reception signal at that time. Display in A mode.

This allows the operator to immediately know that the ultrasonic reception signal is saturated, and also to know the state of saturation from the displayed A-mode image. Therefore, the operator must read this A-mode image and adjust the amplification factor of the receiving circuit to a level that does not saturate.

Since the A-mode image is displayed every time an ultrasonic reception signal is received, the level can be easily adjusted to the optimum level by adjusting the level while looking at the waveform. Furthermore, since saturated ultrasonic reception signals are automatically excluded during waveform analysis, it becomes possible to measure the sound velocity with high accuracy, and moreover, the optimum amplification degree can be easily set. In this way, the received signals for sound speed measurement obtained by repeating the transmission and reception of waves for sound speed measurement are added and averaged, and the peak position of the received signal at the intersection is determined from the time when the wave transmission starts to this peak position. The ultrasonic propagation time is obtained from this time information and used for sound speed measurement.

In this way, the wooden model monitors the saturation of the receiving circuit output,
When saturation occurs in the ultrasonic reception signal for measuring the speed of sound, the operator is immediately notified of this, and the A-mode image of the saturated ultrasonic reception signal output by the receiver circuit is displayed to notify the operator of the saturation state. , the amplification factor of the receiving circuit can be easily adjusted to an appropriate value, and the speed of sound can be measured by analyzing the waveform while excluding the saturated ultrasonic reception signal. Therefore, even if saturation occurs, anyone can easily reset the receiving system to the optimum amplification degree and measure the speed of sound, making it possible to measure the speed of sound with high precision.

(Example) Hereinafter, an example of the present invention will be described 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. However, the receiving circuit 19 here uses a circuit whose amplification factor can be variably adjusted. 18 is A/D
A calculation circuit 25A that performs sonic velocity measurement, average value calculation, etc. based on the output of the converter 20 is a system control means, and is in charge of controlling the entire system. 2G is a changeover switch that selects and switches the supply route of the combined output of the reception 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.

Reference numeral 27 denotes a receiving circuit on the ultrasonic device side, which performs amplification, detection, filtering, logarithmic conversion, etc. of the received signal. 28 is an A/D converter, which converts the output of the receiving circuit 27 into a digital signal.

A marker generator 29 generates image data (markers) for displaying the measurement route (beam bus route) of the cross mode sound speed measurement. Reference numeral 30 denotes a digital skin 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 was collected. At the same time, readout is performed in accordance with the scanning timing of the display 17, thereby adjusting the acquisition timing of the ultrasound image and the display 11.
By interposing this frame memory, differences in display timing can be converted without any problems. Further, the output of the marker generator 29 is sent to a position corresponding to the measurement route of the cross-mode sound velocity measurement of the B-mode image on the frame memory of the digital scan converter 30.

The memory 22 also updates and stores the data of the A-mode image. Furthermore, although not shown, the display 17 has a video RAM 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 the one explained in the prior art section regarding 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 16, the loading and reading control of the memory 22, the operation control of the waveform analysis circuit 24 and the calculation circuit 18, and the changeover switch. 26, marker output control of the marker generator 29, etc. Then, while normally performing ultrasonic scanning for B mode, in between (every predetermined timing) ultrasonic transmission and reception for cross mode sound velocity measurement is performed, real-time display of B mode and sound velocity measurement are performed. Then, it performs sound speed measurement calculations, displays the results, calculates the average sound speed of all beam buses, and displays the results in plots.

Furthermore, in this system, the output of the receiving port path 19 is supplied to the A/DI converter 20 via a saturation detector 31 that detects saturation of the signal level, and the saturation detection output of the saturation detector 31 is sent to the processing circuit. 23 and system control means 25A. When receiving the saturation detection output from the saturation detector 31, the processing circuit 23 is configured to exclude the saturated ultrasonic reception signal from the averaging process. Further, upon receiving the saturation detection output from the saturation detector 31, the system II output means 25A displays an A-mode image of the ultrasonic reception signal that has detected saturation on the display 17, and also displays a separately provided light emitting diode (LED) 32.
The buzzer 33 is also turned on and sounds to notify the operator that the output of the receiving circuit 19 is saturated. Further, the system control means 25A outputs a message code to notify the saturation to the character generator 34 for generating character information, converts this message code into a character video signal by the character generator 34, and provides it to the display 17, so that the operator can also This is to let you know when it's saturated.

If saturation is detected in this way and the saturation situation is concretely displayed in the A mode, it will send a message and light,
And, the occurrence of saturation can be immediately notified by sound.

Note that the normal A-mode display is performed by immediately displaying the measurement data for each beam path obtained by the above-mentioned cross-mode sound velocity measurement. This is an A-mode image display, an average A-mode image display,
Each of the selected beam paths is displayed in the form of an average sound speed change diagram or a local sound speed change diagram.

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

That is, as shown in Fig. 2, in this 8i setting, the local sound speed of the abnormal part included in the reflection points (measurement points) PI3 and PI3 at the upper boundary and the reflection point (measurement point) PIlO at the lower boundary is measured. , the ultrasonic beam transmission and reception path is A-)
pHo −+B, A−+Pt l−+C, B−+Po
Try to take four routes: O→A, B-+Pt 2-eD. 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, and Pa++
The wave reflected at POO is received at position 8, then transmitted from position A, the wave reflected at Prt is received at position C, then transmitted from position 8, and the wave reflected at POO is transmitted at position A. By switching the transmission and reception, such as receiving, then transmitting from position 8, and receiving the reflected wave from PI3 at position D, the measurement path is symmetrical.
The directional directions of the A sound wave beams in the transmission and reception directions are made to be at the same angle θ. Then, each time you enter the sound speed measurement mode, you can select to measure one of the four routes in turn, or change to the next other route every time you measure the same route several times. It shall be executed in an appropriate order, such as

Next, 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 Bl, B2, and B3 as shown in FIG.

B4 is used for measurement, and each reflection point (beam intersection) is set in advance by the operator at the optimal depth close to the target area by referring to the B-mode ultrasound image. shall be. Further, the operator sets a cross-mode sound velocity measurement route by referring to the 8-mode ultrasonic image.

As a result, the system control means 25A controls the marker generator 2.
9 to generate image data (marker) for displaying the measurement route of the cross mode sound velocity measurement set above. The output of the marker generator 29 is B on the frame memory of the digital scan converter 30.
Since it is written in the mode image at a position corresponding to the measurement route for cross-mode sound velocity measurement, the measurement route for cross-mode sound velocity measurement set together with the current 8-mode image is displayed as a marker on the display 17.

Therefore, the operator can know in advance how the measurement route is set, and can change the settings if there is a problem.

Once the measurement route has been set in this way, the operator then issues a measurement command to start sound velocity measurement.

This is done as follows. That is, every time the ultrasonic electronic scan in B mode is completed, the changeover switch 2G is temporarily switched from the terminal B side to the X side at a predetermined timing, and the sound velocity is measured on the measurement route at the set starting point position.

To explain specifically, first, the system control means 2
5A, the changeover switch 2G is switched to the terminal B side, the multiplexer 13 is selected for electronic scanning, and the delay circuits 15 and 16 are set to have a delay time for electronic scanning. With these delay times, ultrasonic waves are transmitted and received from the transducer group selected by the multiplexer 13. The combined output of this received signal is amplified and detected by the receiving circuit 27, and then filtered through a low-pass filter (cutoff frequency: 1 MH 7 filtered by degree). After the signal level is checked by the saturation detector 32,
The data is converted into digital data by the A/D converter 28 and input to the digital scan converter 30, and the data is stored in the frame memory location of the digital scan converter 30 corresponding to the ultrasound scan position. These ultrasonic scans are sequentially acidified and converted into digital scans while shifting the scan position in sequence.
An ultrasonic B-mode image is formed in the converter 30.

In addition, the beam bus marker for cross mode sound velocity measurement set by the marker generator 29 is output and placed at the position corresponding to the cross mode sound velocity measurement position in the frame memory of the digital scan converter 30. The marker is 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 17, and is provided to the display 17 for display.

When the B-mode electronic scan is completed, the system control means 25A switches the changeover switch 26 to the terminal X side in order to measure the speed of sound. Then, cross mode sound velocity measurement begins. This sound velocity measurement begins with 8 points at the position set above.
Follow route 1.

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

The delay time difference τ0 between adjacent oscillators is τo = (d/C□) sinθ0 (
The relationship is set so as to satisfy the above equation (2). And the above system 11110 means 25A (7) $1111
1+7) Mo,! :1. : A predetermined number of transmitting vibration elements belonging to point A of the probe 1 are connected to the output ends of the corresponding balsers 14 by the switching operation of the multiplexer 13.

For example, if the predetermined number of transmitting transducer elements belonging to the eight points of the probe 1 (see FIG. 2) is 32, then the transducer group TI, ~T32 and the output end of the balsa 14 are Connected.

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 outputted at a timing shifted by a delay time of 5, and is input to a corresponding transducer of the balsa among the imagers Tl 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 eight points (
By switching the multiplexer 13, a predetermined number of receiving transducer elements belonging to the corresponding delay circuit 1
It is connected to the input terminal of 6.

Here, since the transmitting transducer element is 32 m long, the 32 transducer groups belonging to point B of probe 1 T91° to T12
8 and the input terminal of the reception delay circuit 16 are connected.

As a result, the foot sound beam transmitted toward the subject from the transducer group belonging to point A of probe 1 is received by the reflection valve at point Poo by the transducer group belonging to point B of probe 1. , the echoes are given the same time difference as in the case of transmission by the receiving delay circuit 16, and then synthesized and output.

The reception echo synthesis output from this reception delay circuit 16 is
The signal is amplified and detected by the receiving circuit 19 and filtered (filtering during sound velocity measurement is to clarify waveform distortion caused by speckle noise and improve measurement reproducibility, and a low-pass filter with a cutoff frequency of about 100 kHz is used. ) and after saturation is detected, A/
It is converted into a digital value by the D converter 20 and stored in the memory 2.
2 - gets stuck. In the memory 22, the clock generator 20
The address is updated at a predetermined timing every time the ultrasonic beam is transmitted by the clock signal outputted by the system control means 25A, and the writing control is performed by the system control means 25A, so that the echoes from the measurement points correspond to the time. It will be remembered in the way it was written. This is A mode brass data.

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, using the number of times of ultrasonic transmission and reception in the mode that will occur from next time onwards. Measurement is performed, and the received echoes obtained through this measurement are averaged by the action of the processing circuit 23 with respect to those of the same route (if 81, those of B1).

This suppresses fluctuations.

When this work is completed, the system control means 25A switches the selector switch 26 to the terminal B side again, and enters B mode collection. Then, when the data collection of the B mode image is completed, the system control means 25A switches the changeover switch 26 to the terminal
side, and move on to cross-mode sound velocity measurement on route B2. 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 on the route of the starting point position, a predetermined number of transducer groups belonging to the 0 point of the probe 1 are selected. is connected to the input terminal of the reception delay circuit 16 corresponding to the probe 1, and a predetermined number of transducer groups belonging to the point A of the probe 1 are connected to the corresponding pulser 14, respectively. And A of probe 1
The reflected component at point Pst of the ultrasonic wave transmitted from the transducer group belonging to the point is received by the same number of transducer groups belonging to the zero point of the 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 and saturation detection by the low-pass filter, the output is transmitted from the ultrasonic wave on the route B2 to the reception. It is used for measuring time t2.

When this work is completed, the system l1lil1 means 25A switches the selector switch 26 to the terminal B side again, and the B mode
Execute the collection of de statues. When this is completed, the system control means 25A switches the changeover switch 26 to the terminal xll.
Switch to lIJ and proceed to the cross mode sound velocity measurement on route 83 in the route of the above-mentioned starting point position. Then, under the control of the system control means 25A, the multiplexer 13
operates, and this time, the transducer group belonging to point A is changed to the 8 points of probe 1, and a predetermined number (32 elements in the previous example) of the transmitting transducer group according to the reflection point setting depth is changed to the transducer group belonging to point A. T97
．． ~■ 128 and the corresponding output terminals of the pulsers 14 are connected, and a 32-element transducer group belonging to the A point of the probe 1 is connected to the reception delay circuit 16 instead of the transducer group belonging to the 0 point. Connected. Then, ultrasonic waves are transmitted from the transducer group belonging to the eight points of the probe 1, and the reflected components of the transmitted ultrasonic waves at the point Poo are received by the transducer group belonging to the 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, detected, and filtered by the receiving circuit 19 in the same way as in the case described above, and after the saturation is detected by the saturation detector 32, the time from the transmission of the ultrasonic wave on the route B3 to the reception of the ultrasonic wave is determined. It is used for measurement of t3.

When this work is completed, the system control means 25A switches the changeover switch 26 to the terminal B side again, and executes B-mode image collection. And when it finishes the system Ill
The WJ means 25A switches the changeover switch 26 to the terminal X side, and moves to cross mode sound velocity measurement on the route B4.

The multiplexer 1 is controlled by the system control means 25A.
3 operates, and this time A in the route of the above starting point position
Instead of the transducer group belonging to the point D, the predetermined number of transducer groups belonging to the point D of the probe 1 are connected to the input terminals of the reception delay circuit 16 corresponding thereto, and
Each of the predetermined number of oscillator groups belonging to a point is connected to a corresponding pulsar 14.
connected to.

Then, the transducer group and the input terminal of the receiving delay circuit 1G are connected. Then, when an ultrasonic wave is transmitted from the transducer group belonging to the eight points of the probe 1, the reflected component of the transmitted ultrasonic wave at the point P12 is received by the transducer group belonging to the point D of the probe 1. be done.

Then, the reception echo is processed by the reception delay circuit 16.
After being given the same time difference as in the case of wave transmission, the signals are combined and output. The combined output of the received echoes is amplified, detected, and filtered by the receiving circuit 19 in the same way as in the case described above, and after the saturation is detected by the saturation detector 32, it is received from the ultrasonic wave transmitted on the route B4. Time to wave t4
used for measurement.

When this work is completed, the system control means 25A switches the changeover switch 26 to the terminal B11Il again, and executes B-mode image collection. And after its completion, system i
ll 111 means 25A connects changeover switch 2G to terminal x
Il, and proceed to the cross-mode sound velocity measurement on route 81 at a new position where the ultrasonic sensor is moved, for example, by one pitch with respect to the route at the above-mentioned starting point position.

A plurality of echo signals collected by repeating such operations are obtained as a summed average value of the respective echo signals in the four routes 81 to B4, as shown in FIG. In addition, real-time B
A mode image is displayed.

In this way, the measured values for each measurement route are averaged and stored. This stored data is read out from the memory 22, and the peak position is determined by the waveform analysis circuit 24.

Then, information on the address where the data corresponding to the determined peak position is stored is sent to the calculation circuit 18 as time information. Based on this, the calculation circuit 18 calculates 81.8.
2.83.84 Time tl, t2. from ultrasonic transmission to the above peak position for each route. t3. t4 is calculated. After that, the sound speed values Vl and V2 for each route are further
, V3, V4, and the average sound velocity value (■) and local sound velocity value in the entire beam bus, etc., are calculated and displayed on the display 17.

The above is an operation when there is no saturation in the output signal of the receiving circuit 19, but when saturation occurs, the following operation occurs.

That is, since the output of the receiving circuit 19 is given to the A/D converter 20 via the saturation detector 31 that detects the saturation of the signal level, the saturation detector 31 immediately detects the saturation when the output signal level of the receiving circuit 19 is saturated. It is detected and a saturation detection output is provided to the processing circuit 23 and the system control means 25A. Then, upon receiving the saturation detection output from the saturation detector 31, the processing circuit 23 excludes the saturated ultrasonic reception signal from the averaging process. That is, adding the output of the A/D converter 20 to the memory 22 is prohibited. Further, upon receiving the saturation detection output from the saturation detector 31, the system system means 25A displays an A-mode image of the ultrasonic reception signal detected in the t1i phase on the display 11, and displays a separately provided light emitting diode (L E D ) 32 and buzzer 33
lights up and sounds to notify the operator that the output of the receiving circuit 19 is saturated. In addition, the system control means 2
5A outputs a message code notifying saturation to a character generator 34 for generating character information, converts this message code into a character video signal by the character generator 34, and supplies it to the display 17, notifying the operator of saturation also in text. Therefore, the operator must
9. Immediately know that the output is saturated. The operator then sees the A-mode image of the saturated received signal displayed on the display 17 and knows the degree of saturation. Next, the operator adjusts the amplification factor of the receiving circuit 19. The output of the receiving circuit 19 during this adjustment is controlled by the system control means 25A so that the amplified output of the received signal obtained each time the sound velocity measurement mode is entered is displayed on the display 17 in the form of an A-mode image. The receiving circuit 19 can be easily adjusted to an appropriate amplification factor while observing the state of this A-mode waveform. Then, when the adjustment is completed, a sound velocity measurement start command is given to the system control means 25A, so that the sound velocity measurement using the received signal at the optimum amplification factor is carried out. Note that once saturation is eliminated, the LED 32, buzzer 33, character display, and saturated A mode waveform display disappear.

In this way, the present invention detects the saturation of the receiving circuit, concretely displays the saturation situation in the A mode, and can immediately notify that saturation has occurred with a message, light, and sound. This is what I did. and,
In order to specifically notify the saturation state, the A-mode waveform of the saturated reception signal is displayed so that the amplification factor of the receiving circuit can be adjusted while viewing the actual waveform state.

Therefore, with this device, even if saturation occurs in the received signal when measuring the speed of sound, anyone can immediately know this, adjust the receiving system to the optimum amplification factor, and measure the speed of sound. Therefore, it becomes possible to measure the speed of sound efficiently and with great precision.

Here, an example of the display on the display 17 of this device is shown in FIG. In the figure, 51 is a B-mode image, 52 is a beam bus marker indicating the route of the beam bus set for the cross-mode sound velocity measurement in this region of interest, and 53 is the beam bus obtained by the cross-mode sound velocity measurement.・A mode image for each route, 54 is each sound speed value for each beam bus route obtained by the above cross mode sound speed measurement, 55
is a diagram of changes in the average sound speed value of the target region determined based on the respective sound speeds for each beam, bus, and route. The beam bus marker 52 is the one described above in B1. ~B4 route movement! Among these routes, the sound speed 11354 indicates the sound speed value of route 1 to B1 above as vl, the sound speed value of the above B2 route as V2, the sound speed value of the above B3 route as V3, and the sound speed value of the above B4 route as Vl. The sound speed value of Rou () is numerically displayed as v4, and the average sound speed value at the local (beam intersection) is numerically displayed as ■[. Note that ■ is the average sound speed value of these four routes. !In, 57 shows the average A mode image of each route. Also, the above average sound speed value change diagram 55 shows the time change of this average sound speed value. B1 and 83 are 81, B3 is B2 and 84 are 8
It is displayed as 2.84. Further, the A mode waveform at the time of saturation may be displayed in the section 53 together with a message notifying the saturation.

In addition, in the ultrasonic wave transmission and reception in the cross-mode sound velocity measurement described above, this device calculates the moving distance of the center position in the transducer arrangement direction of the transducer group belonging to point A and the transducer group rotting at point D, and B. As shown in FIG. 2, the moving distances of the center positions of the transducer group belonging to the point and the transducer group belonging to the zero point 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 with respect to the line that passes through point Poo and is perpendicular to the ultrasonic wave transmission and reception surface of BuO-Bu1, and The distance is Δy.

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

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

Δt-[(tl-t2) + (t3-t4))/2-((tI+t3)/2)-((t2+t4)/2)...(10) By executing the calculation of this equation (10), The obtained Δt is the point Ps! →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 calculates the point pH→point POO→point P1.
The average sound speed C^ of the ultrasonic waves propagating along the path between the two is determined by the following equation.

CA-(Δy-co)/(Δt-8inθ0)...(
11) The average sound velocity calculated by this equation (11) represents the sound velocity in a local area of the internal tissue of the subject (in this case, a region including point PIIIPOOIP12).

In this way, the sound velocity in the local tissues of the subject's body can be revealed from the reflected components of the ultrasound waves at the 23 points Ptt, Poo, and Pl. By appropriately switching the multiplexer 13 and changing the intersection point of the directional directions in the transmission and reception of ultrasound, the sound velocity at multiple locations in the internal tissue of the subject can be determined without changing the deflection angle θ.

FIG. 3 is a diagram showing a region where the local sound speed 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 and output the path as a marker.

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

In this case, (Poo * Pl s
*P12), (Ptt, P2t, P22).

(Pl2.P22.P2:l), (P21, P3t
.

Pl2), (P22.Pl2.Plri.

(P2B, Pl3.Pl4), etc., in line with the abnormality to be measured, pass through the first intersection and this first intersection, and perpendicular to the ultrasound transmission/reception wave surface of the probe 1. The second one has a line-symmetrical positional relationship with the line as the axis. Selecting a combination of three reflection points at the third intersection, performing the above measurement on the filtered reflected waves using the ultrasonic beam passing through the above-described route at the three intersections,
By calculating the average sound speed by calculation of equation (11),
Measurable area 11! ! The distribution of the average sound speed at a desired local area within 31 can be obtained.

The sound velocity value of the desired local area filtered out by the calculation circuit 18 can be displayed as a sound velocity 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.

Here, C is the unsampled averaged sound velocity information, and N is the number of combinations of intersection points used to calculate the local sound velocity, which is 3 in this embodiment.

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 using equation (13), the supersonic wave propagation time is first unsampled averaged, and the average result is used to calculate (
14) Calculate the equation to find the sound speed value C.

Δt=(1/N)Σ(Δti)...(13)\
1=1 (14) The unsampled average result of the sound speed values thus obtained is displayed on the display 17 as shown in FIG.

Further, by using the collected data of all the ultrasonic beam transmission/reception routes collected during the sound velocity measurement mode for obtaining the ultrasonic propagation velocity information, the measured value of the sound velocity in each route is obtained, and this is displayed on the display 17. 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 for the same route is obtained by the calculation circuit 18, and each is given to the display 17 as shown in FIG. , is displayed at a predetermined position and in a predetermined format.

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.

〔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, even if the received signal waveform becomes saturated due to saturation of the receiving system during data collection for sound velocity measurement, the operator can This information can be immediately notified, anyone can objectively set the amplification factor of the receiving system to the optimal value, and saturated waveforms are automatically excluded from sound speed measurement, so the sound speed can be measured with high precision and efficiency. It is possible to provide an ultrasonic diagnostic device with a cross-mode sound velocity meter 114 function that can perform measurements, has good operability, and is highly reliable.

[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. , Figure 5 is a diagram to explain the averaging, Figure 6 is a diagram to explain the relationship between reception system saturation and peak point detection error generation, and Figure 7 is a diagram to explain 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, Figures 9 to 11 are diagrams for explaining its operation, and Figure 12 is a conventional Figures 13 and 14 showing examples of display displays of the device
The figure shows speckle reduction and time position measurement using a conventional device F!
FIG. 4 is a diagram for explaining the relationship between the occurrence of four differences. 1... Probe, 13... Multiplexer, 14.
...Balsa, 15...Delay circuit for transmission, 16...Delay circuit for reception, 17...Display, 18...Calculation circuit, 1'll, 27...Reception circuit, 20.2
8... A/D converter, 21... Clock oscillator, 2
2... Memory, 23... Processing circuit, 24... Waveform analysis circuit, 25A... System control means, 26...
Changeover switch, 29... Marker generator, 3o...
Digital scan converter, 31... Saturation detector, 32... LED, 33... Buzzer, 34...
・Character generator, T1・. ~T128...Ultrasonic imaging device. Applicant's representative Patent attorney Takehiko Suzue Figure 3 Figure 4 Figure 5 Amplitude (V) Figure 6 Figure 11 Figure 12 + t + t ■ + + in Figure 13

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 grouped together, and a wave transmission path is created in a predetermined direction to the target region of the subject. A group of different ultrasonic beam transmitting and receiving groups, respectively, in order to transmit the ultrasonic beam using the ultrasonic beam and receive the ultrasonic beam at the target site using a receiving path in a predetermined direction that intersects with the transmitting path. Ultrasonic waves are transmitted and received using an ultrasonic vibrating element, the peak of the reflected wave from the target area is detected, and the time required from the transmission to the peak reception is measured to determine the propagation of the ultrasonic wave at the target area. An ultrasonic diagnostic apparatus equipped with a sound speed measurement function that obtains speed information and uses it for diagnosis, includes a receiving circuit with a variable amplification factor that detects and amplifies an ultrasonic reception signal in a sound speed measurement mode in which the sound speed is measured; a saturation detector that monitors the level of the receiving circuit output signal and detects when it is saturated; a control means that notifies you when this saturation is detected and controls to display an A-mode image at that time; Equipped with analysis means for determining the peak position of the received signal from the target area and obtaining the ultrasonic propagation time based on the data obtained by averaging the received signals excluding the ultrasonic received signal detected at saturation during measurement. An ultrasonic diagnostic device.