JPS62106748A - 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 ultrasonic diagnostic apparatus for diagnosing tissues within a subject using ultrasonic waves, and particularly for measuring ultrasonic wave propagation velocity in tissues. The present invention relates to an ultrasonic bath@device for characterizing and diagnosing tissues.

(Technical Background of the Invention) The ultrasonic wide velocity in a subject is influenced to a large extent by the composition present in the ultrasonic transmission path in the subject.

In other words, this means that it is possible to detect, for example, lesions in organs, etc., or liver cirrhosis, etc., by the ultrasonic propagation speed in the living body. Measuring the transmission speed (there is a clinically large 1iIIIi value).

Therefore, using this fact, 1. Attempts have been made to obtain information on the wide range of ultrasonic velocities in living organisms, and to use this information to examine the composition at target locations.

Conventionally, the most common ultrasonic measurement method for such inspections is to use two transmitting and receiving probes, sandwich the subject between the two probes, and calculate the sound velocity from the distance between the probes and the transmission time. How to ask.

(2) Using the ultrasonic Doppler effect, the blood flow detection position and l!
A method of determining the sound speed from the shift of the Ii layer image.

(3) When synthesizing tomographic images, vary the sound speed settings and find the sound speed setting that best brings the images into focus.
How to use this as the customer speed value.

etc.

However, in method (1), the target parts that can be measured are limited, and in particular, it is not possible to measure parts located in the body that are thick, such as the liver.

In addition, method (2) requires searching for a suitable blood vessel, is difficult to operate, and takes time, so it is not suitable for clinical use.

Furthermore, in (3), since the image must be focused, pattern 01 must be created manually, which is time consuming and causes great fatigue for the subject.

There is a drawback. Therefore, a method as shown in FIG. 4 using an electronic scanning ultrasonic diagnostic apparatus was developed.

That is, in the figure, 1 is a probe for ultrasonic linear electronic scanning, and using this probe 1, ultrasonic pulses are emitted into the body in the θ direction from one MfA of the ultrasound receiving surface 2 that is in contact with the body surface (not shown). fire.

Here, an electronic scanning type ultrasound device is one that includes multiple ultrasound transducers (hereinafter simply referred to as transducers). Using a probe with an array of ultrasonic transducers arranged in a straight line, several adjacent sensors in this probe are grouped together, and the direction of the transmitted ultrasound beam and its beam are determined for this group of sensors. A driving pulse is applied to each transducer with a predetermined delay time determined according to the position of the transducer in the oscillator, and the ultrasonic waves are excited. In this method, the waves cancel each other out in some areas and strengthen each other in other areas, resulting in an ultrasonic beam. Wave reception is generally performed using the group of oscillators used for wave transmission, and the detection signals of the oscillator group are delayed by the delay time during wave transmission, thereby aligning the time axes and combining them. Let it be the received signal. Since the position of the generated ultrasonic beam shifts by shifting the group of imagers by -pitch, it is possible to select the vibrator to be excited at once and control the excitation timing. , a linear scan can be performed, and a sector scan can be performed at a desired position.

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 receiving path 5 is received not by the transducer group used for transmission, but by the transducer group at the incident position of the echo that has arrived (the transducer group at the right end B of the probe 1). let

Since the distance 11y between A and B is known, the route 4.5
By measuring the wide width time t of the ultrasonic waves that widen the width, the sound velocity C in the liver tissue can be determined by C=y/(t-sin θ) (1).

This principle is used to measure the speed of sound.

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

In the figure, reference numeral 1 denotes an ultrasonic blower 7, and the probe 1 is constructed by linearly arranging transducers TI to T128 of, for example, 128 elements for transmitting and receiving ultrasonic waves. Oscillator T1
, ~T128, the juxtaposed surfaces become the ultrasonic wave transmitting/receiving surface 2 of the probe 1 in FIG.

12 is a lead wire; 13 is a multiplexer which is a circuit selection switch; 14 is a transmission delay element for obtaining a delay concavity to be given to each of a group of vibrators to be excited;
5 is a balsa that generates pulses for ultrasonic excitation drive, 1G
17 is a receiving delay circuit for obtaining the echo delay amount necessary for aligning the time axis etc. according to the receiving direction and element position for each of the group of transducers used for reception, and 17 is a receiving delay circuit for obtaining image, text information, etc. 18 is a calculation circuit, 19 is a transducer T96 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; A/D to convert
Converter, 21 is an oscillator that generates a clock signal for sequentially updating the address for the mesori in order to sample and store the rate pulse signal for driving the pulser and the echo from the target object part, and 22 is a received signal storage. A memory 23 is used to store the memory 22 each time an ultrasonic pulse is generated.
A processing circuit for adding the stored data value at the same address and new input data, averaging it, and storing the added average value at the corresponding address;
This is a waveform analysis circuit that examines data indicating a peak value using the sample values of the received waveform that has been subjected to averaging processing and is stored in the , and calculates the time (address) of the data having the peak value. The calculation circuit 18 is this waveform analysis circuit 24.
Calculate the transfer time t from the time information obtained, and
It has a function of calculating sound velocities at a plurality of localities in the internal tissue of the subject based on the obtained record time t, and spatially averaging and outputting the results. 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 25 controls the operation of the multiplexer 13, sets the delay times of the transmission delay circuit 15 and the reception delay circuit 16, and controls the memory 2 according to a predetermined program.
2 and controls the operation of the calculation circuit 18.

The above-mentioned camera elements Tl, -T128 are excited and emit ultrasonic pulses when voltage pulses are applied, and generate voltages when the ultrasonic pulses are incident. 128-element vibrator T1.
~T128, for example, the element width a of each vibrator is set to 0. ay
As s, this is the pitch between the element centers d=o, 7
128 elements are arranged linearly at intervals of 2ttm. 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 rate pulse of 4 kHz 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 driving, and the outputs of these 32 pulsers 14 are sent to the A end of the 128 imagers Tl to T128 by the multiplexer 13, which is a switching circuit. TI, ~T32
are input in a one-to-one correspondence.

Also, camera element T1. ~T128 contacts the body surface through the coating material of the probe 1, and the ultrasonic waves output from the transducer element are transmitted into the living body.

Standardly, the speed of sound in living tissue is Co = 1530 f
If m/S1, the delay time r(.

τo-(d/Co)-sin θo-(2), and the transmission delay circuit 15 is set so that each element is driven with such a delay time difference.

That is, pi)1 = O, PO2-τo, PD3-2
τ0, . . . A delay time of P D 32=32τ0 is given.

If the sound velocity in the living tissue is Co, the ultrasonic beam will travel in the θ0 direction, but it is generally not limited to Co and has a different value C. The transmission direction θ of the ultrasonic wave at this time is sinθ/C=s i nθo/Co 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 RDi-31τ0, RD2=30τo,
--, RD3+-τo, RD32=0.

In this way, even if the ultrasonic beam transmitted in the 00 direction at the sonic speed Co has a sonic speed C in the living body and has directivity in the θ direction, the transducer element i T97. ~T128 has directivity in the θ direction and receives reflected waves from the θ direction. The received signal is amplified, detected, and logarithmically converted in three circuits 19, and
. The memory 22 stores lO based on the timing of the rate pulse.
The addresses are updated sequentially in synchronization with the MHz clock, and sample 1 of the received waveform stored in the memory 22
The 7th dress exactly matches the time from the time when the output sound pulse is issued, for example, with an accuracy of 100 ns intervals. Therefore, from the address, the time when data at that address was obtained (the elapsed time from the time when the ultrasonic pulse was emitted) can be determined.

The peak value of the stored waveform indicates a foul wave from point P,
If the waveform analysis circuit 24 detects the time (address) of the peak value, the wide time V can be determined. Substituting the above equation (3) into equation (1), the speed of sound in the living body CC = v'VCo/(t-s
1 n θo ) −(4). Furthermore (
4) Substituting equation (2) into equation C-ge7] side f]: in]
...(4'). Since V, d, and τ0 are known, the calculation circuit 18 calculates the above equation <4'' using the wide time t threatened by the measurement to obtain the value of the sound speed C, and outputs it to the display 17.

FIG. 6 is a time chart showing a method for measuring the wide time t, in which an ultrasonic pulse is emitted at a time slightly delayed from the fall to of the rate pulse of (a>).The time of the peak of the pulse 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 a liver, for example, λ, it is indicated by a point P, and the vicinity thereof is relatively uniform liver tissue.

Therefore, the reflected wave from the vicinity of point P is relatively uniform.
This becomes a reflected wave from 11a. Of these reflected waves, the one that reaches the earliest is the one that goes through the 21st point in FIG. 7, and the one that arrives the latest that goes through the 92nd point. 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 Fig. 6(b), and since the tissue is not completely uniform and is a living tissue, various scattered ultrasonic waves are formed, and N. Since the signals are received including speckles as a result of mutual interference, various random irregularities occur in the waveform.

Therefore, since the peak value cannot be detected with this method, by moving the probe a little, we can obtain echo data with the position of the beam intersection in the liver slightly shifted, and by performing llD '13 on these data, we can detect the simple tone component. Turn it so that it doesn't disappear. In other words, since the unevenness of the waveform in (b) is considered to be random, the waveform can be made quite smooth by changing the beam intersection and adding hundreds to tens of thousands of 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 wide time t as t-t2-tl.

Now, using 3.5M output as the ultrasonic frequency, V = 4
8. Assuming that the ultrasonic beam is focused near the intersection point Pn, the beam width (about 17% at the peak in transmission and reception) near the point P is about 2#.

At this time, the propagation time difference Δt between the one passing through 21 points and the one passing through 92 points is about 4.5 μs.

When C=Co, the ultrasound beam direction is θo
=30', the propagation time t is approximately 62.7 μs. Since the measurement accuracy of the beam value at time t2 is considered to be less than 1/10 of Δt, it can be said that the sound velocity measurement error is less than 10 m/'s.

The sound speed measured in this way is the path 4 and 5 in FIG.
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 finding the average sound speed in the vA weave near two points, but if the above-mentioned method is further improved, it is also possible to measure the local sound speed. The method is shown using FIG.

FIG. 8 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. The B-mode @30 obtained by electronic scanning is displayed on the display 17, and the travel path set for sound velocity measurement is also displayed superimposed on the B-mode image using a marker. Reference numeral 31 indicates fat and muscle layers of the subject; 32 is a cross section of the liver showing a muscular parenchyma; 33 is a 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 (located at the intersection of the beam direction directions for both transmitting and receiving) is Pi, 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 point P1. The extended line position of PO is marked as ○, and in the wide path of the ultrasonic beam with 21 points as measurement points, the emission points of probe 1 are A and B, the input points are B and Ol, and the PO point is the measurement point. The emission points on the transmission path of the ultrasonic beam are C and D.
, the incident points are D and ○, and the extension line position of the measurement points PI and PO at probe 1 is ○, and the ledger path passing through each of these points is <A-+B, A→O, B-+Q, COD,
Propagation time t(AB>, t(A
O), t (Bob, t (CD).

Find t(CD>, t(Do).

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

The ultrasonic propagation time between PO-8 is POB, the ultrasonic propagation time between PO→○ is poo, the ultrasonic propagation time between c-pi is CPL, the ultrasonic propagation time between P1→DP1 is PID
, Plo is the ultrasonic propagation time between Pi→O, and using these, t(AS) is calculated.

t (AO), t (BO), t (CD), t (CD
)t (Do). That is, t (AB>=APO+POB t (AO) -APO+ (t Q/2) +P1
0t (BO) -BPO+ (tffi,'2)
+Pi Ot (CD)=CP1 +PI D t (Co)=CP1 +P10 t (Do) -DP1+p10 (5) From this, tλ can be found using the following equation.

t/l= [(t (AO)+t (BO)-t(AS
))-(t (CO) +t (Do)-t (CD)
) i... < 6) Therefore, the distance between Pi and PO is ×2, and the average sound speed is C2
, the distance between AB is VO, and the distance between CD is yl, (1=2Xri/1g = (1-1i/(t!2-tanθ)...(7) Xn= (yo -yl) /2tanθ・(8)
The local speed of sound C2 can be found as . As the value of θ, using the average sound velocity C of the normal liver part, θ=sln from equation (3)
' ((C/Co) ・sin θ.) (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 the incidence of the beam on the boundary is close to perpendicular (
If you press the button, there will be less error. 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. 8, 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 ultrasonic wide path display marker are displayed on the display, and used for diagnosis as well as for photographing or Save by recording a video.

[Problems with the Background Art] By the way, such sound speed measurement is called cross mode sound speed measurement, but in the case of the conventional method described above, the wide path (A→ B,
A→O, B→O1C→D.

A total of six different propagation paths (C→O, D-+O) were measured over a wide range of time to determine the local speed of sound. By measuring three paths for one measurement point in this way, we can measure the differences in the thickness of the body surface and subcutaneous tissues caused by the ultrasonic beam entering and exiting obliquely. The accuracy is improved by reducing the influence of

However, in cross-mode sound velocity measurement using the electronic scanning method, when changing the measurement point, the delay time of the transmitting/receiving delay circuits 15 and 16 and the position of the transmitting/receiving transducer group are controlled by the system control means 25. For each such measurement point, for example, an ultrasonic beam is transmitted from point A of probe 1, received at point B, and then an ultrasonic beam is transmitted from point B. In the case of a three-path method, in which an ultrasonic beam is transmitted from point A and received at point 0, and then an ultrasonic beam is transmitted from point A and received at point 0, each possible measurement point (this depends on the hardware) In addition to each delay time setting value per measurement point, considering the relationship of
Selection data for three sets of transmitting and receiving transducer groups to be selected must be prepared, and the program and data for the system control means 25 become enormous.

This causes complexity and waste in hardware and programs, resulting in increased costs.

In addition, 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 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, which is the lack of measurements on the path from D to C, the average is statistically non-uniform.
Strictly speaking, the problem remains that the above error cannot be reduced.

(Object of the Invention) The present invention has been made in view of the above circumstances, and its purpose is to reduce the programs and data of the system control means, eliminate waste in circuit control, and
An object of the present invention is to provide an ultrasonic diagnostic device having a cross-mode sound velocity measurement capability that can improve measurement accuracy, simplify control sequences, simplify hardware, and reduce costs. .

[Summary of the Invention] In other words, in order to achieve the above object, the present invention uses a probe configured by arranging a plurality of ultrasonic transducer elements in parallel, and groups a predetermined number of adjacent ultrasonic transducer elements of the probe into a group. At the same time, a group of different ultrasound beam transmitters and receivers that can transmit and receive ultrasound beams at the same angle are used to transmit and receive ultrasound beams from the target region of the subject. By detecting the reflected waves and measuring the time required from transmission to reception, information on the ultrasonic propagation speed of the target area is obtained, and the ultrasonic diagnostic equipment used for diagnosis can perform the above measurements on the subject. A control means performs control so that the above-mentioned detection measurement is performed at least once for each ultrasonic beam transmission/reception path in which the outgoing direction and the return direction are set as a set, and an average The present invention is characterized in that it is constructed using a calculation means for determining the ultrasonic wide-range velocity.

Using a probe configured by arranging multiple ultrasonic transducer elements in parallel in this way, among the ultrasonic imaging elements of this probe,
A predetermined number of adjacent ultrasound beams are grouped into a group, and ultrasound beams are transmitted and received using different groups for transmitting and receiving ultrasound beams that can transmit and receive ultrasound beams at the same angle to the target region of the subject. by detecting the reflected wave from the target area and measuring the time required from transmission to reception of the wave to obtain ultrasonic wide velocity information of the target area,
In the ultrasonic diagnostic apparatus used for diagnosis, the above detection measurement is performed at least once each with the outward direction and the backward direction set as one set for each ultrasonic beam transmission/reception path used for the above measurement of the subject by the control means. control to carry out,
As a result, per route, detection measurements are performed an even number of times (at least 11 and 2 times) with the sending and receiving directions reversed to ensure symmetrical measurements, and based on the information obtained from these detection measurements, the calculation means is used to calculate the average value. By finding the ultrasonic propagation speed of
It is possible to reduce errors by making the average statistically uniform. In addition, by making measurements symmetrical for each path, it is possible to reduce the number of programs and data for the control means, eliminate unnecessary circuit control, and improve measurement accuracy, simplify control sequences, and reduce hardware costs. To enable simplification and cost reduction.

[Embodiment of the Invention] Hereinafter, an embodiment 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 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 generator, 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.

This device is basically the same as that described in the prior art section, but in this device, the functions of the conventional system control means 25 are set as follows for the configuration shown in FIG. The difference is that the calculation contents of the calculation circuit have been changed as follows.

25A is the system control means used in this device,
There is no difference from the conventional system in that the system is mainly configured with a CPU (central processing unit; for example, a microprocessor). This system control means 25A controls the operation of the multiplexer 13, sets the delay time of the transmission delay circuit 15 and reception delay circuit 16, writes and reads Mla of the memory 22, and the calculation circuit according to a predetermined program. Here, the operation of the multiplexer 13 is controlled as follows.

That is, as shown in Fig. 2, this device measures the local sound speed of the abnormal part included in the reflection point (measurement point) Pll and PI3 at the upper boundary and the reflection point (measurement point > PG a) at the lower boundary. , the ultrasonic beam transmission and reception path is A-*P.
o Q-+B, A-JP+ 1→C, B-+Po O-
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, the reflected wave from PIIO is received at position B, and then the wave is transmitted from position A,
What is reflected by Pll is received by cmi, then transmitted from position B, what is reflected by P++a is received by position A,
Next, by switching the transmission and reception in such a way that the wave is transmitted from position 8 and the wave reflected by PI3 is received at position D, the measurement path is symmetrical, and the direction of transmission and reception of the ultrasonic beam is The orientation directions of the two are set at the same angle θ. In this way, programs and data are simplified and unnecessary control is eliminated. Furthermore, by making the measurement route symmetrical, the above-mentioned statistically non-uniform average can be avoided, thereby making it possible to reduce errors.

Furthermore, since there are now four wide paths to measure,
Instead of the conventional calculation circuit 18, the calculation circuit 18A of this device
Here, a calculation circuit +8A is used which has the functions of calculating the propagation FRrF5 in each path, calculating the wide time estimate value based on the following equation (10), and calculating the average sound speed using the equation (11).

Next, the operation of this device having the above configuration will be explained.

This device has four routes B1.82 as shown in Figure 2.
, B3.84.

First, measurements are taken on route B1.

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

This delay time is set so that the delay time difference τ0 between adjacent camera elements has the relationship τo−(d/Co)sinθ0 (formula (2) above). Then, by the switching operation of the multiplexer 13, the transducer group Tl, ~T32 belonging to the point A of the probe 1 and the output end of the pulser 14 are connected.

Further, a rate pulse is generated by the clock generator 21 and is input to the pulser 14 via the transmission delay circuit 15. Then, from the pulser 14, the corresponding transmission delay circuit 1
The excitation pulse is outputted at a timing shifted by a delay time of 5, and is input to the corresponding SvJ element of the pulsar among the transducers TI to T32, and the transducer generates an ultrasonic wave. Then, it is transmitted as 81 sound wave beams in a predetermined direction θ determined by the delay time.

On the other hand, under the control of the system control means 25A, the delay time of the transmission delay circuit 16 is set, and the multiplexer 13
Due to the switching operation of transducer group T97. belonging to point B of probe 1. ~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 has a reflected force at point Poo, and is received by the transducer group belonging to point B of the probe 1. The echoes are combined and output after being given a time difference similar to that in the case of transmission by the reception delay circuit 16.

The reception echo synthesis output from this reception delay circuit 16 is
After being amplified and detected by the receiving circuit 19, 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.

When the above-mentioned ultrasonic transmission and reception is performed multiple times by the transducer groups belonging to each of points A and B of the pro nib 1,
By the action of the processing circuit 23, the received echoes are averaged.

The data stored in this way is read out from the memory 22, data indicating the peak is examined by the waveform analysis circuit 24, and the data is sent to the calculation circuit 18A as information on the address where the data is stored or time information. . Based on this, the calculation circuit 18A calculates the time t1 from the transmission of the ultrasonic wave on the route B1 to the reception of the above-mentioned peak.
is calculated.

Next, we move on to measurement on route 82.

The multiplexer 1 is controlled by the system control means 25A.
3 operates, and this time, instead of the transducer group belonging to point B, the transducer group belonging to point 0 of probe 1 and the receiving delay circuit 16 are activated.
The reflected component at point P1 of the ultrasonic wave transmitted from the transducer group connected to the input end of probe 1 and bent at point A of probe 1 is
The wave is received by the transducer group belonging to the 0 point of the probe 1.

Then, the received echo is processed by the receiving delay circuit 1G.
After being given the same accuracy as in the case of wave transmission, the signals are combined and output.

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

Next, we move on to measurement on route 83.

The multiplexer 1 is controlled by the system control means 25A.
3 operates, and this time, instead of the transducer group belonging to point A, the transducer group T96° to T128 belonging to point B of probe 1 is connected to the output end of the pulser 14, and the vibration belonging to point 0 is connected. Instead of the child group, a group of transducers belonging to point A of the probe 1 is connected to the reception 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. Then, the reception echoes are given a time difference similar to that for 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 above case, and is then used to measure the time t3 from transmitting the ultrasonic waves to receiving the waves in the steps 1 to 1 of B3. be done.

Next, we move on to measurement on route 84.

The multiplexer 13 operates under the control of the system control means 25A, and this time, instead of the transducer group belonging to the point A, the transducer group belonging to the D point of the probe 1 and the input terminal of the receiving delay circuit 16 are connected. Connected. And B of probe 1
When an ultrasonic wave is transmitted from the transducer group belonging to the point, the reflected component of the transmitted ultrasonic wave at the point P12 is reflected by the probe 1.
The wave is received by the transducer group belonging to point D. Then, the reception echoes are given a time difference similar to that for 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 then used to measure the time t4 from transmitting the ultrasonic wave to receiving the wave on the route B4.

In the above ultrasonic wave transmission/reception, this device uses the moving distance of the center position in the transducer arrangement direction of the transducer group seen at point A and the transducer group belonging to point D, and the transducer group belonging to point B and the zero point. As shown in FIG. 2, the movement distance of the center position of each of the transducer groups in the transducer arrangement direction is 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 a line that passes through point Poo and is perpendicular to the ultrasound transmission/reception wave surface of probe 1, and the distance between them is △ It becomes y.

Here, point Poo, point Pi 1 , 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, the time t1 obtained by the above-mentioned ultrasonic wave transmission and reception.
~t4 is used to cause the calculation circuit 18A to execute the following calculation.

△t-((tl-t2)+(t3-t4'))
/2-((t1+t3)/2)-((t2+t4)/2
) ... (10) This (
10) Δt obtained by executing the calculation of formula is the point pH →
This is the estimated propagation time value of the ultrasonic wave propagating along the path between point Poo and point P12.

Therefore, the calculation circuit 18A calculates the point pH→point Poo→point P.
The average sound speed CA of the ultrasonic waves propagating along the path between 12 and 12 is determined by the following equation.

CA-V(ΔV-Co)/Δt-5ln.

(11) In this case, the average sound velocity calculated by equation (11) is local to the internal tissue of the subject, at point P11. POO.

represents the speed of sound in the region (including PI2).

In this way, it is possible to calculate the sound velocity locally in the internal tissue of the subject from the reflection components of the ultrasound waves at 23 points of pH, POO, and PI. 13, by appropriately switching and changing the intersection position of the directional directions in the transmission and reception of ultrasound waves, it is possible to determine the sound velocity at multiple localities in the tissue within the subject's body 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,
The above intersection points are specified.

28 in the figure is the measurable region of local sound velocity, and this i region 2
8, denoted by the symbol Poo, ~P2+ [•J is the intersection point of the ultrasonic transmission/reception directional direction.

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

PI3), (Pll, P21.P22).

(PI2.P22.P23), (P21.Pll.

Pyo 2), (P22.P32.P33).

(P23, P33, Pyo4), ..., in line with the abnormal part to be measured, passing through the first intersection and this first intersection, and with respect to the ultrasonic transmitting and receiving wave surface of the probe 1. The second. Third
By selecting a combination of three reflection points at the intersection of , performing the above measurements on the reflected waves passing through the above-mentioned routes for the three intersections, and calculating the average sound speed by calculating equation (11), It is possible to obtain the distribution of the average sound speed at a desired location within the measurable region vJ,28.

The desired local sound velocity value calculated by the calculation circuit 18A is displayed on the display 17 after being subjected to brightness modulation or color modulation.
is displayed as a sound velocity distribution. Further, the results are spatially averaged in the calculation circuit 18A as described below, and then output to the display 17.

This averaging (unsampled averaging) is performed using the following equation.

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, which is, for example, 3 in the case of this embodiment.

Also, unsample averaging can be performed as follows.

That is, from each combination of three intersection points, the ultrasonic propagation time is first unsampled averaged using equation (13) with the measured wide time Δti as Δti, and the average result is used to calculate
Calculate equation (14) to find the sonic field C.

(14) The unsampled average result of the sound speed values obtained in this way is displayed on the display 17 (for example, as a text display).

In the first embodiment described above, since the unsampled average results of the sound velocity values at multiple locations in the internal tissue of the subject are displayed, macroscopic changes in a predetermined part of the subject, for example, the entire liver, are displayed. It is possible to obtain sound velocity information that reflects the speed of sound, and it is particularly effective in diagnosing organs such as the liver, whose internal tissue is homogeneous when the tissue is in a normal state.

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. For example, in the above embodiment, the probe A
Although we have described a system in which ultrasonic waves are transmitted from a group of transducers belonging to point or point D and received by a transducer group belonging to point B or point 0 of the probe, different methods are used for transmitting and receiving ultrasonic waves. The same effect can be obtained even if the vibrator group is reversed to the above case. Furthermore, in the above embodiment, the delay times of the transmitting delay circuit and the receiving delay circuit are set so that the delay time difference τ0 between adjacent vibrators satisfies the relationship (2) above. Focal length of the sound beam beam l! ! The delay time τ(X
) may be used.

τ(X) = (f/Co) Here, X is the position @ (coordinate) of each transducer in the probe transducer group in the arrangement direction. When the delay time is set in this way, the intersection area of the ultrasound beam's pointing direction matches the focal point of the ultrasound beam, and the area of the intersection area of the pointing direction becomes smaller, resulting in a steep peak in the received waveform. . Therefore, the peak value of the received waveform can be detected accurately, and the local sound speed can be measured with high precision.

In this way, the present invention uses a probe configured by arranging a plurality of ultrasonic vibrating elements in parallel, and sets a predetermined number of adjacent ultrasonic vibrating elements of this probe into a group. , using a group of different ultrasound beam transmitters and receivers that can transmit and receive ultrasound beams at the same angle, perform ultrasound transmission and reception, detect reflected waves from the target area, and receive from the transmitted waves. By measuring the time required for the wave to reach the target area, information on the ultrasonic propagation speed of the target area is obtained, and in the ultrasonic diagnostic apparatus for diagnosis, the ultrasonic beam transmission and reception path for the measurement of the subject is controlled by the control means. For each route, control is performed so that the above detection measurement is performed at least once with the outgoing direction and the returning direction as a set, and thereby, 11 constants are performed on both the reciprocating routes with the sending and receiving directions reversed for each route. Therefore, instead of the conventional asymmetrical measurement, symmetrical measurement is performed, and by calculating the average ultrasonic propagation velocity using a calculation means based on the measurement result, it is possible to obtain a statistically uniform average. Therefore, it is possible to reduce erroneous attachment. In addition, by making measurements symmetrical for each path, the control I-sequence can be simplified, the programs and data for the control means can be reduced, there is no wasted circuitry, and it is possible to simplify the hardware and reduce costs. .

(Effects of the Invention) As described in detail above, according to the present invention, errors are reduced, and therefore high-precision sound velocity measurement can be performed, and there is no wasted circuitry, simplification of hardware, and It is possible to provide an ultrasonic diagnostic apparatus having features such as being able to reduce costs.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention;
Figure 2 is a diagram for explaining the present invention in detail, Figure 3 is a diagram for explaining the measurement point setting area in the probe of this device, and Figure 4 is for explaining the principle of cross mode sound velocity measurement. FIG. 5 is a block diagram showing the configuration of a conventional ultrasonic diagnostic apparatus that performs cross-mode sound velocity measurement. ~FIG. 8 is a diagram for explaining the operation. 1... Probe, 13... Multiplexer, 14.
...Pulser, 15...Delay circuit for transmission, 16...Delay circuit for reception, 17...Display, 18A...
Calculation circuit, 19... Receiving circuit, 20... A/D converter, 21... Clock oscillator, 22... Memory, 2
3... Processing circuit, 24... Waveform analysis circuit, 25A.
...System control means, T1. ~T128... Ultrasonic imaging device. Applicant's representative Patent attorney Takehiko Suzue Figure 2 Figure 3 Figure 4 Heeeeeeeeeeeeeeeeeee →←--tg! 7!6 Figure 7 Figure 8

Claims (1)

[Claims] Using a probe configured by arranging a plurality of ultrasonic transducer elements in parallel, a predetermined number of adjacent ultrasonic transducer elements of this probe are grouped together, and a target region of the subject is
Using a group of different ultrasound beam transmitters and receivers that can transmit and receive ultrasound beams at the same angle, perform ultrasound transmission and reception, detect reflected waves from the target area, and receive waves from the transmitted waves. By measuring the time required for the measurement, information on the ultrasonic propagation speed of the target area is obtained, and in the ultrasonic diagnostic equipment used for diagnosis, the ultrasonic beam transmission and reception path for each ultrasonic beam transmission and reception path used for the above measurement of the subject is a control means for performing control so as to perform the detection measurement at least once or more for each direction and return direction as a set; and a calculation means for calculating an average ultrasonic propagation velocity based on information obtained by the detection measurement. An ultrasonic diagnostic device characterized by comprising: