JPS6368142A - Ultrasonic diagnostic apparatus - Google Patents

Abstract

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

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) This invention relates to a @sonic diagnostic device that uses ultrasound to obtain information inside a living body, and in particular, it relates to a ultrasound diagnostic device that uses ultrasound to obtain information inside a living body. The present invention relates to an ultrasonic diagnostic device having a function of measuring the speed of sound waves.

(Prior art) Diagnostic methods using ultrasound have the advantage of being able to diagnose soft tissues without placing any burden on the patient, and are non-invasive, and have the benefit of recent advances in high-speed scanning. It has rapidly spread due to Since this ultrasonic diagnostic method is a pulse reflection method, it is superior in operability compared to the transmission method, and the diagnostic sites to which it can be applied are not so limited are also cited as reasons for its widespread use.

For such ultrasonic diagnostic methods, there has recently been an increasing demand for quantification of 0 images.

It is considered particularly effective in differential diagnosis of benign and malignant organ diseases. However, in the conventional pulse reflection method, the reflected wave intensity is determined not only by the difference in acoustic impedance (the product of degree and sound speed) between tissues in the body, but also by the shape of the reflecting surface, the angle of incidence of the ultrasound beam on the reflecting surface, and the Quantification of a single image has been extremely difficult because it is difficult to separate and detect these pieces of information.

On the other hand, the conventional method of measuring only sound waves is transmitted ultra-f-wave C.
Although it is still in the research stage, its performance is gradually improving (Reference: Greenlea
f, J, F, et, al, Acoustical H
olography.

vol, 61975) *However, the transmission method is
It cannot be applied to areas with bones or gas in the shaft, so it can only be used in very limited areas such as mammary gland examinations. The major drawback is that it cannot be used.

On the other hand, a method has been devised in recent years to measure the sound velocity within a single device using the pulse reflection method. Figure 7 shows the method for measuring the sound velocity in liver wax reported by Akamatsu et al.

This uses two ultrasonic transducers 51$52 with strong directivity for transmission and reception, respectively, and the ultrasonic waves transmitted from the transmitting ultrasonic transducer 51 are centered on each transducer 51s52. It is reflected near the intersection 0 of the axes ppl and QQI.

The time it takes for the ultrasonic wave to reach the receiving ultrasonic transducer 52 and to be received is measured, and from this time and the expected propagation distance calculated from the distance X and angle θ between the transducers 51 and 52, the liver This is a method to find the average sound speed within.

This method produces a uniform sound throughout the liver! It is considered to be effective in diagnosing chronic diseases such as liver cirrhosis that have # characteristics, but the obtained sound speed is the average sound speed within the propagation path, so 1
It cannot be applied to localized diseases. Furthermore, since the ultrasonic waves propagate through the epidermis or fat layer, which has a different sound speed than the inside of the liver, there is a problem that the measurement error in bit speed is large.

In response to such problems, the present inventor previously proposed a local sound velocity measurement method using a pulse reflection method.

Figure 3 shows a diagram of its principle, in which transmitting transducers 41, 44 and receiving transducers 42, 43 are placed on the body surface as shown in the figure, and the region ABCD surrounded by the transmitted and received ultra-f-wave beams is The time t11*tlm from when the W wave transmitted from the transducer 41 is scattered by the scatterers at A and B until it is received by the transducers 42 and 43, during which the sound speed Co is estimated, is shown in each case. Similarly, when the sound velocity transmitted from the transducer 44 is disrupted by D and C and received by the transducers 42 and 43, the propagation time is 11tll. /Co-
,2゜1,,-1. C+1. C, but I 'GAItKAI'FC1tHC
are GA, EA, PC, HCIC respectively.
Time -1. Here, the incident angle of the transmitted beam is θoEF−
do, then the propagation time Δt is Δt-t,,-t,,+t,,-t,,-(AB+BC
+AD+CD)/C.

That is, the sound speed Co in the region of interest is the propagation time difference Δt
It can be determined from the following equation by determining .

However, in the local sound velocity measurement shown in Figure 3 above, two transducers are placed on the body surface for each transmitter and receiver.
These four types of special propagation times tll! +wtlsj□
When finding the speed of sound in the region of interest from

If there is a medium between the transmitting/receiving transducer and the region of interest that prevents the beam from proceeding, a portion of the 4O propagation times cannot be measured, making it impossible to accurately determine the local sound velocity. There is a problem when you can't do it anymore.

(Problem to be solved by the invention) In this way, in conventional manufacturing, if there is a medium between the transmitting/receiving transducer and the region of interest that blocks the beam, it is difficult to accurately determine the local sound velocity. The problem is that it is no longer possible to ask for

The present invention has been made to solve these problems.

[Structure of the invention]

(Means for Solving Problems) The present invention calculates the peak position of the waveform after adding and synthesizing four types of internally reflected signals obtained by combining two transmitting transducers and two receiving transducers. It is characterized by measuring the propagation time by calculating the center of gravity or the like.

(Function) Since the propagation time is calculated after the four receivers No. 9 are detected, the probability that the calculation will not be possible is greatly reduced, and stable local sound velocity measurement is always possible. Furthermore, due to the inhomogeneity of wood fiber inside the body, it can be an effective means for determining the accurate speed of sound even when the ultrasonic beam is extremely diffused.

(Example) Before describing the example, the problems with the conventional method described above will be explained using a specific example6.For example, if there is a transmitting transducer as shown in FIG. As shown in (a), the received Ig number P turtle (t) Pa (l P
g(t) Pa(t) is obtained. However, p+(t) is GAE P, (t) is GBF P, (t) is HCP
'P, [t) indicates the waveform propagated through the HDE and received, the propagation time at this time '11 ttt ill
If you try to calculate tll from the center of gravity, it will be difficult to receive the scattered waves from the medium 4509 point 0 or point D. Therefore, it is not possible to accurately calculate t and t□, so in such a case, Until now, it has been impossible to estimate the local speed of sound.

The present invention has four waveforms P before the propagation time begins.

+1) to P4 ft) v synthesis, and the propagation time (2) is calculated from the composite waveform's 7:1 center of gravity, thereby attempting to improve the above-mentioned problem.

2S: The waveform synthesized in the invention is shown in Figure 5(b)!
D, and can be expressed by the following formula A(t).

A(t)-P, (t)+P weight ttl+ps (t)+
P, (t) −(6) where Ps (t
) + P * (t) and P, (t) 10 Pa (t) can be calculated separately because their reception times are far apart.

If the center of gravity of these ■ is ta tb, -(force, and when there is no obstructive medium 45, JP Hatake (t) dt-Io holds in general for JP, (t) d, so ibm - (t, , +t,, ) Therefore △j-1-txt -ttt+ to -jtm-2
The speed of sound Co can be determined by substituting (tb-ta)-(9) into (4).

On the other hand, if the mediator 45 exists, p, (t):zOPa
(If szO, then tas=xt1.tbwt,.

If the transmission velocity sentences of AE and CF in the four factors of joy are approximately equal, the local sound velocity can be determined to be positive 1 in the area of interest (ACID)'7). On the other hand, AE ■ Speed of sound and CF
D If the sound speeds are not equal, there will be an estimated difference of 11/D
According to Tsugisen, the calculation is not impossible as in the conventional method.

The special feature of wood fiber is that when there is a t3 substance 45 between the transmitting/receiving transducer and the region of interest O that can significantly impede the propagation of sound waves, it automatically eliminates the propagation time of the sound waves O passing through this medium. This is to prevent a large "n output difference O'#" from occurring.The above explanation deals with the case where the medium 45 exists between the transmitting beam and the region of interest, but when the medium 45 exists between the receiving beam and the region of interest. The present invention also has similar effects.

FIG. 1 is a part 191 of the present invention and shows the configuration of an ultrasonic disassembly device that is capable of measuring local sound velocities within the body. The transmitting transducer 2.3 and the receiving transducer 4.5 are placed on the body surface as shown in Figure O. The transmitting transducers 2 and 3 radiate ultrafracture pulses into the living body 1 driven by drive pulses supplied from the pulsers 6-1, 6-2. The wave pulses are scattered within the living tree tissue, but the ultrasound waves scattered at points DA and 9 in the 1''4I heart region are transmitted by the receiving transducer 4 to points B and C. The scattered ultrasonic waves are received by the reception transducer 5.

The signal received by the receiving transducer 4.5 is amplified by the amplifier 7-1.7-2.

, +* Wave circuit 8-1, 8-2 generates an envelope negative wave, and adder 9 adds and synthesizes the 0-synthesized signal. The signal is converted into a digital quantity by A/D'R conversion δ and then calculated. The propagation time is calculated in the device.

However, this Va combination A, a, (,: from point O scattering and his synthesis and [3, aD from point 7) W! The propagation time is calculated from each of the L random waves and the synthesized wave D, and the local sound speed in the body is determined using equations (9) and (4).

On the other hand, the region of interest can be moved to any desired location by mechanically moving the transmitting receiver (! transducer 2 = 3-4e5) or by varying the transmitting beam angle. It is also possible to calculate the sound velocity distribution and display it on the C-T 14 via the frame memory 13.

Figure @2 is a configuration diagram showing the O-pond O-containment arrangement of the present invention. This ■
In this case, the transmitting/receiving transducer 2*3*4t5 is used only for each container selected by the switch circuit 'JI&1B-1$18-2. Therefore, the waveform P+(t)
~Pa (1) is obtained by four transmissions and receptions, and these D
The waveforms are stored in a memory 15 for A/D conversion and then synthesized in an adder 9. Compared to the method O shown in FIG. 1, this method takes more time to disclose, but has the advantage that the electronic circuit is only 1125.

FIG. 6 shows another embodiment of the present invention, and shows a part of a play-type sonic transducer based on the present invention, which is used to obtain in-vivo osmosis 11 by electronic scanning.
This is the column used for IF wave total velocity measurement.

That is, among the many arrayed transducer elements constituting the play-type superrenal anti-transducer 30, the 31.347) area shown by 8+sand is used for transmission, and the 32 and 330 areas shown by diagonal lines are used for reception. A sword is used.

When transmitting ultrasonic waves from the area 31 of the play-type ultrasonic wave transducer 30, by shifting the drive timing of the adjacent plurality of V pendulums in the area 31 by a predetermined time using a delay means, The beam can be deflected, for example, as shown in FIG. The same applies to 34.

As a specific driving method for performing such electronic deflection and rounding to 5, for example, the method described in Japanese Patent Publication No. 56-IC158 can be used.

This D embodiment has excellent phagocytosis because it is possible to measure the local sonic velocity using a square array type ultra-wave transducer, and it also has real-time display of B-mode radiation. This has the advantage that it is easy to accurately set the region of interest in which the crestal sound velocity is to be measured. In addition, by electronically changing the transmitting/receiving ultrasonic transducer O vertical position (regions 31 to 347) and the transmitting ultrasonic beam D deflection angle easily and quickly, the ultrasonic O transmitting area and receiving area Since it is possible to change the intersection area between D and D, it is possible to obtain the D local sound velocity Dit of the D local Mi wave in the living body, and furthermore, it is possible to display the two-dimensional sound velocity distribution O. That is, it is possible to obtain the in-vivo superconcussion sound velocity distribution using the pulse reflection method, which was previously impossible.

In addition, in the present invention, the transmitting and receiving transducer is arranged! The first method is not limited to three configurations, and the number of transducers υ is not limited as long as they are each two or more.

[Brightness effect]

According to the present invention, it is possible to determine the local speed of sound inside the body even when there is a medium that blocks the propagation of sound waves in a part of the body.9. This can be an effective means especially for displaying two-dimensional sound velocity distribution.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are respectively block diagrams of an ultra-f wave diagnostic apparatus according to an embodiment of the present invention, and FIG. 3 is a diagram showing the principle of the local sound velocity measurement method. 1... Living tree, 2.3... Transmission transducer. 4.5...Receiving transducer, 6...Pulser. 7...Amplifier, 8...Detection circuit, 9...Adder,
10... A/D converter, 11... Oscillator, 12...
・Arithmetic unit, [3...Frame memory, 14...CR
T, 15...Memory. 41.44... Transmission transducer, 4 L
43... Receiving transducer, 45... Sound wave propagation blocking medium, 51... Transmitting transducer, 52
...Reception transducer, 30...Array type transducer, 31s34...Transmission transducer group, 32@33...Reception transducer group. 26...Body surface. Agent Patent attorney Nori Chika Weight Kikuo Takehana Dimensions Figure 3 Figure 4

Claims (1)

[Claims] A plurality of transmitting transducers that transmit ultrasonic waves into a medium, and receiving areas arranged so as to intersect the transmitting areas of the transmitting transducers in the medium, and receiving reflected waves of the ultrasonic waves from within the medium. After the ultrasonic pulses emitted from the plurality of reception transducers and the transmission transducer are scattered in the transmission and reception intersection area,
An ultrasonic diagnostic apparatus comprising means for measuring the time until reception by the receiving transducer, and means for calculating the speed of sound in a medium from the propagation time and the positional relationship between the transmitting and receiving transducers. An ultrasonic diagnostic device characterized by performing calculations for measuring propagation time after adding up each signal obtained by the combination.