JPS6024829A - 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 [Description of the field to which the invention pertains] The present invention relates to an ultrasonic diagnostic apparatus that measures the attenuation characteristics of tissue using an ultrasonic pulse echo method and provides it as diagnostic information.
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[Description of prior art]

Attempts have been made to measure the attenuation characteristics of living tissues using the I3 sonic pulse echo method and use it for differential diagnosis between normal and abnormal tissue, and its effectiveness in the clinical field is beginning to be recognized (e.g., Roman Kuc,” Cl
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” T E E E T trans, vol[3ME
-27No., 6June 1980, etc.). The basic idea is shown below. Ultrasonic pulses emitted from the ultrasonic transducer 1 to the living tissue 2 (if the living tissue is uniform, the ultrasonic pulses are scattered or reflected by countless points and return to the transducers 1 to 2). However, if the spread of the sound field between 1 and the transducer can be ignored, the amplitude of the transducer received by the transducer is considered to have uniform tissue attenuation information. That is, the first
As shown in the figure, now the distance from 1 to Lance des Users is
Considering two points A and B in the living body, x1 and x2, the amplitude spectrum of the echo returning from point A VA (f) (f:
Comparing the amplitude spectrum VB (1゛) of the echo returned from point B with the amplitude spectrum VB (1゛) of the echo returned from point B, we get the following equation, where the amplitude spectrum of the emitted pulse is Vo (f). α(f) is the attenuation constant of the tissue and represents the amount of attenuation per unit length.

When the equation 0 is transformed, the meaning of this equation is that the attenuation constant of the tissue can be obtained from the positions of points A and B and their amplitude spectra.

To do the above experimentally, as shown in Figure 2, the time when the ultrasonic pulse is emitted is O, and the time of the ultrasonic reception echo is t1 = 2X1 / C (C: the sound speed of the ultrasonic pulse). ) d3 and t2=2xz /C waveform (a
) with a certain finite width τ j~(b),
It is sufficient to obtain the amplitude spectra (c) and (d). In this way, 1ql=spectrum is shown in FIG. 3A in FIG. 3, and the ratio thereof is taken in FIG. 3B. ■By the formula α([)
can be calculated.

■As can be seen from the process of deriving the equation, if there is a non-uniform substance between the △ point and the three points, the value of α(f) will include the attenuation effect of the intervening substance, so The desired homogeneous portion damping constant will not be obtained. Therefore, in order to accurately obtain information on only the desired homogeneous Ti portion, it is necessary to take measures to prevent heterogeneous portions from entering between Goo 1 and Goo.

In addition, in the received echoes from the uniform countless point reflectors, a pattern of strength and weakness appears as a result of countless echoes from each point reflector or negative interference, and a so-called speckle pattern appears on the B mode. However, this speckle does not represent the actual distribution of dots, but is due to the distance and azimuth resolution of the ultrasonic pulse. In FIGS. 3(a) and 3(b), ripples are generated in the spectrum due to the influence of this speckle, and these ripples become an error factor in measuring the attenuation of biological tissue.

[Purpose of the invention]

This proposal avoids the above-mentioned inhomogeneity, enables accurate gate position setting, reduces errors caused by ripples without appearing in the received echo spectrum, and achieves a high S/N ratio and high accuracy. The purpose is to provide an ultrasonic diagnostic device for obtaining diagnostic information.

[Explanation of IM composition and operation of the invention]

Tree j1? The plan is to observe the B-mode image using a linear array 1 Herance Duel, and then apply Goo 1- to the received echo of the Single 1~Lance Deuser, which has been aligned with the predetermined axis on the displayed B-mode image. In the configuration where the attenuation constant is calculated from the above formula
In addition, in order to smooth out the ripples in the spectrum mentioned above, the ripples as shown in Fig. 4 were eliminated and accuracy was improved by processing the temporally different single 1~Lance de user receivers. It is something.

FIG. 5 shows an embodiment of the present proposal, and shows the positional relationship between the linear array, the single 1-lance decoder, and the living body. What is the linear array 3 and single 1 lance decoder 4?
The ultrasonic emission direction of the linear array and the ultrasonic emission direction of the single lance ducer are aligned at an angle of θ on the plane at the center of the slice plane of the array, and molded with resin in the probe case 8. has been done. 9 is an ice bag, which is used to improve the acoustic coupling between the lance decor length and the living body.

FIG. 6 shows a display example. As shown in Fig. 15, the positional relationship between the near array and the single 1 to the lance decoder is set in advance. It can be displayed like a dotted chain line.

Therefore, while observing this B-mode image, the operator determines the gate positions on the dashed-dotted line as shown at 6'-1 and 6-2. This will prevent inhomogeneous substances from entering.

Moreover, the problem of spectrum ripple can be alleviated as follows. If the beam position and gate position of a single transducer are the same and the position of the living body does not move, the information obtained will be the same no matter how many times ultrasound is transmitted and received at that position. Due to sexual migration and other factors, the position of each organ changes slightly over time.

In other words, even if the beam position and gate position of a single transducer are fixed, the influence of the spectra changes over time due to the movement of the organ. Therefore, the spectrum can be smoothed by repeating the same steps 1 to 1 and detecting the average or maximum value.

Also, to touch on the advantages of using a single transducer for attenuation constant measurement, one is that by using a large-diameter single transducer, it is possible to transmit and receive ultrasonic pulses using N goes to -E.

Another reason is that the broader the band of the ultrasonic pulse, the more information about the attenuation constant α(f) is jt'l J, so (1) 1-rans pheri + < 1 ! Unfortunately,
A single transducer can be manufactured relatively easily compared to array 1 to lance transducers and the like. Also, normal B
Since the transducer used to construct the mode image focuses the ultrasound beam to improve lateral resolution, the beam width of the ultrasound beam in the depth direction is not uniform. For this reason, when using a focused ultrasound beam to measure the attenuation constant, the effect of the difference in beam width will be included as an attenuation effect, so the received echoes of parts with very different beam widths will be used to When calculating the formula, correction is required. Therefore, for the purpose of the present proposal, a 1-lance duplexer without focusing is suitable. For the above reasons,
By using a large-diameter, wide-band flat-plate single transducer, an inexpensive device with good S/N ratio and high precision can be realized.

FIG. 7 is a block diagram of the embodiment. Figure 7 shows the entire system, but the difference between this embodiment and the conventional one is the part surrounded by solid lines in the figure, so this part will be explained, and the other parts will not be explained in detail. Omitted.

First, using the output Sn of the limp ring signal generator 17 as a basic clock, a signal 5VL obtained by frequency-dividing the basic clock is output from the rate signal generator 16-1. Similarly, the single transducer signal Svs is output from the rate signal generator 16-2. Both 5yb and Svs are signals that give pulser drive timing, but the linear array and single 1- The transducer is driven alternately.

Data regarding the gate position and gate width set by the operator is stored in each latch 31. GA, GB are goo 1-
A.Displays the position data on 13. Goo 1~
The signal generator 32-1 sends the data of GA and τ to Goo 1 for the period “I 11I from the position GA to τ, and for the rest (L
A signal of 011 is output, and the switch 27-1 is turned on by this output signal. As a result of this operation, only the received echoes for the period corresponding to gate 8 are captured in memory A. The same is true for B.

In this embodiment, the following explanation will be given assuming that the memories Δ and B are memory capacity for predetermined M numbers (-). That is, the rate signal Svs
During M periods of , the memory △ contains −1,..., M;
is the frequency of SO + 11]) and tl'3, and B also contains similar waveform data VnjkT (). After running SvS for M periods, VAj(
kT) VBj(kT) is taken into the computing unit 2,
The result is input to the frequency analyzer 30, where the spectrum calculation and the calculation of the equation 0 are performed. It will be done. The result is D/△
It is converted and sent to the display 34.

FIG. 6 shows an example of the display according to this embodiment, in which 6-1 and 6-2 are markers that do not indicate the gate position, and the gate marker generator 3
3 generates J-ru. Further, 35 is a display example of α(f).

Also, since α (') increases almost linearly with frequency f, this part is approximated by a straight line, and the slope of that straight line is β (neper/cm, M 1 - I Z or d It is also effective to display B/cm-fvll-1z>.

[Explanation of modification]

In this example, a B-mode image-like 1 to Lance du 4-C Linino 1 array was used, but a phased array (
The same is true even if sectors) are used.

[Brief explanation of the drawing]

Figures 1 to 3 are detailed explanatory diagrams of the present invention, and Figure 4 is a diagram showing the spectrum and attenuation constant in which the ripple in J5 in Figure 3 has been eliminated by deductive processing and the error has been reduced. , FIG. 5 is a diagram showing the linear array (~transducer and single 1 ~ lansde) --→no and the positional relationship of the living body, and FIG. 6 is a diagram showing an example of the display according to the embodiment of the present invention.
FIG. 7 is a block diagram of the embodiment. 14...Pal υ, 15...Transmission delay circuit,
16... Rate signal generator, 17... Generates rimbling signal, 18...
・ Preamplifier, 19 ・・ Reception delay circuit, 20 ・
・・・ Adder, 21 ・・・ Logarithm j (width unit, 22
... Detection circuit, 23 ... A/D converter, 24
... Frame marking, 25 ... D/A converter, 26 ... Main amplifier, 27 ... Switch, 28 ... Memory, 29 ... Arithmetic unit, 30
... Frequency analyzer, 31 ... Latch, 32
... Goo 1 ~ Signal generator, 33 ... Gate marker generator, 3.4 ... Display device attorney Kensuke Norichika and one other person) Figure 1 Time t

Claims (1)

[Claims] A means for transmitting and receiving pulsed ultrasound using a plurality of array transducers to form a B-mode image; a means for transmitting and receiving a C-pulse ultrasound using a single 1-lance duel; and formation of a transducer using the array. means for setting the direction of the ultrasonic beam to be produced and the direction of the ultrasonic beam forming the single beam in a predetermined positional relationship;
~ Lance Deco I Sunite if? means for selecting only a predetermined portion of the received echoes; a calculation means for detecting the shoreline average or maximum value among the selectively divided waveform data; An ultrasonic diagnostic apparatus comprising means for calculating attenuation characteristics in a living body using waveform data of at least two points having a distance from the center of an aperture surface on an axis perpendicular to the surface.