JPS58183151A - 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 to which the invention pertains] The present invention relates to an ultrasonic diagnostic apparatus that corrects the sensitivity of ultrasonic echoes.

[Prior art and its problems]

Ultrasonic diagnostic equipment emits ultrasonic pulses into a living body, receives ultrasonic echoes reflected from the interface between tissues with different specific acoustic impedances (the product of the density of both media and the speed of sound), and then This process is used to obtain ultrasonic echoes. This ultrasonic diagnostic apparatus has the advantage that it does not cause radiation exposure damage unlike the X-ray diagnostic method, and can observe tomographic images of soft tissue without using a contrast agent. - Furthermore, the recent development of devices that employ electronic scanning methods has made it possible to perform high-speed scanning, making dynamic measurement easier, improving operability, and increasing the utility of ultrasonic and sonic diagnostic methods. .

An example of a conventional ultrasonic diagnostic apparatus is shown in FIG. In the figure, reference numeral 1 indicates a probe having a piezoelectric vibrator, which is an electro-acoustic conversion element. 4. At this time, if there is a living body set 415 with different acoustic impedance (sound velocity and density product) in the living body 4, a part of the ultrasound waves will be emitted from the body tissue 5. It is reflected at the boundary surface.This ultrasonic echo is converted into an electrical signal by the electro-acoustic conversion element of the same probe 1 used at the time of transmission.At this time, the reflected wave at the boundary surface The acoustic impedance is determined by the value of the specific acoustic impedance.Also, since the ultrasonic echo reflected from the boundary surface of the living tissue 5 takes some time to propagate within the living body 4, the ultrasound echo reflected from the deep part as shown in FIG. The echoes arrive at the probe 1 with a time delay.Due to this difference in arrival time, the tomographic image of the living body 4 cut by the flat shell including the body cannot be expressed as an image. It must be noted that the reflection intensity of the light is influenced by the characteristics of the shallow tissue and varies.

This will be explained using a model of media A, B, and C as shown in FIG. The ultrasonic wave T emitted from the probe 1 is reflected by only a part of the island at the interface between the mediums A and B, and the remaining ultrasonic wave T1 is transmitted through the medium B. Then, the ultrasonic wave T is further reflected by al at the interface between the media B and C, as described above. The interface between the media B and C is displayed on the cathode ray tube 71 by receiving this ultrasonic echo R, by the probe l. In this case, it can be seen that the ultrasonic echo is affected not only by the reflected waves at the interface between the medium A and the medium C, but also by the reflection coefficients at the medium A and the medium B.

Furthermore, since absorption of ultrasound occurs in the medium A and B, the amplitude of the ultrasound echo is affected. That is,
There may be a medium interface with a high reflectance in the shallow part of the living body.

Alternatively, if there is a medium with a large absorption coefficient, an acoustic shadow or a decrease in sensitivity will occur in the image behind (in the deep part of) the medium.

Conventionally, in order to solve various problems caused by such phenomena, 8'l"C (Sensitivity Time
Control) method is adopted. This STC method temporally controls the gain of the receiver during one operation, so that the display of near-field and far-field ultrasound echoes is uniform.
This is a sensitivity correction method that amplifies ultrasound echoes from deep inside. This method is effective when the amount of attenuation (due to anti@ and absorption) in each medium is predicted in advance and each medium has relatively uniform conditions, but it is possible to If large substances are present, it may not be possible to complete the process.

[Purpose of the invention]

This invention was made to solve the above-mentioned problems. 1. Even when JfIJllK with a locally large reflection coefficient exists, it is possible to accurately compensate for the sensitivity of the received signal, thereby improving the analytical ability. The purpose is to provide a capable ultrasonic diagnostic device.

[Summary of the invention]

The transmission circuit drives the electroacoustic transducer to radiate ultrasound into the living body, and the ultrasound echo reflected at the interface of the medium is received via the electroacoustic transducer, and the amplitude of this received signal is A sensitivity correction function is obtained by integrating the function, and the sensitivity of the wetting key signal is corrected based on this function to remove the influence of the acoustic characteristics of the shallow part of the body on the image of the deep part of the body.

〔Effect of the invention〕

According to this invention, by correcting the sensitivity in accordance with the reflection intensity of each medium in the living body, it is possible to reduce acoustic shadows in the shallow part of the living body, thereby significantly improving analytical ability. .

[Embodiments of the invention]

An example of the present invention will be described below with reference to the drawings. In FIG. 4, reference numeral 11 denotes a probe equipped with an electroacoustic conversion element for converting electrical vibrations into mechanical vibration energy, and a pulse generator 13 is connected to this probe 11ζ via a transmitter, for example, a pulser 12. The pulser 12 is driven by pulses from the pulse generator 13. (Then, the electroacoustic transducer of the probe 11 is driven by one output pulse of the pulser 12.

Ultrasonic pulses are emitted into the living body.

On the other hand, ultrasonic echoes reflected at the interface between tissues with different intrinsic impedances in the living body are received by the probe 11 and converted into electrical signals by the electroacoustic transducer. After this electric signal is amplified by a preamplifier 14 at the receiver ζ, a logarithmic amplifier 15 performs logarithmic compression of the width of the received signal. After the output signal of the logarithmic amplifier 15 is sent to a detector 16 and detected.

It is sent to the numbing device 17. Also, the output of preamplifier 14, 3
The signal is integrated by an integration 419 via the detector 18, and becomes a step-like tB force as shown in FIG. The output C is combined with the output of the detector 18 and a sensitivity correction force 5 is performed.

That is, it is corrected and displayed on the display a22 by the step-like sensitivity correction function shown in FIG. 5(a) as shown in FIG.

In the case of the conventional σ) sensitivity T correction using the STC method described above (as shown in Fig. 5(b), the output which increases by 110 on a straight line with respect to the time scale is calculated by 0 as a sensitivity correction function). The super-echoes of deep forces are amplified to a greater extent than one fc.
) is corrected as follows. Therefore, it is effective when the amount of attenuation is uniform, but it cannot be applied sufficiently when there is a large substance. .

On the other hand, in this invention, since step-like correction is performed by integrating ultrasonic echoes, even if there is a material with a locally large reflection coefficient, its influence can be reduced and the analysis can be made more difficult. can be improved.

Note that the step-like output of the integrator 19 is not directly applied to the adder 17, but the integrator 20 is
If the signal is converted to a slope signal as shown in Figure ff), sudden changes on the screen can be prevented, making diagnosis easier.

Furthermore, the output of the 8TC function generator 21 similar to that shown in FIG. 5 1bl is added to the adder 17 to correct the absorption of ultrasonic waves in the medium.

A more realistic picture of the guest can be obtained, making analysis easier.

According to the ultrasound diagnosis of this invention, the shallow sound'! 11
1! ! It can reduce the degree of influence of the hospital on the deep part. In the case of the B-mode method, acoustic shadows have traditionally been actively used to diagnose one area, but in the case of the C-mode method, shallow and deep areas can be simultaneously examined using a single trench. Since this is not possible, it is particularly important to dam up the influence of shallow areas. Therefore, the ultrasonic discursive method according to the present invention is more effective in the case of the C-mode method.

It should be noted that this invention is not limited to the above-mentioned embodiments, and may be modified and modified without departing from the gist thereof.

For example, this invention can be used for low-speed running f14 using a single probe f, or for double-speed mode b2l). Kokichi, which also applies to cases, is e-kiru.

[Brief explanation of drawings]

, $ l t4 shows an example of the conventional ultrasonic diagnostic system.
3! ] is an explanation of the action of iku1 ['7)-ilt tA,
The 41st block diagram shows a practical example of this invention, C8
Figure 5 shows the relationship between the received signal and the sensitivity correction function in the same super-example.・・Biological body 5...Sound-biological body with different impedance @ Textile 6...
Receiving circuit 7...Brown tubes A, B, C-Medium To -T+ -a Sound wave, sound, turtle...Ultrasonic echo 11...Probe 12...Pulser 13...
・Pulse generator 14... Preamplifier 15... Logarithmic amplifier 16... Detector 17... Adder
18... Transverse wave device 19.20... Integrator
21... STC divergence generator 22 Braun tube (Figure 1) Figure 2 (a) Figure 3 Figure 4 Figure 511I

Claims (1)

[Claims] fl) An electroacoustic transducer, a transmitting circuit that drives the electroacoustic transducer to emit ultrasonic waves, and a receiver that receives ultrasonic echoes from the electroacoustic transducer and amplifies the received signal. A circuit, a display for displaying the output of the receiving circuit, and means for integrating the amplitude of the received signal to obtain a sensitivity correction function and correcting the sensitivity of the received signal based on the function. Ultrasound diagnostic equipment. (2) The ultrasonic diagnostic apparatus according to claim 1, wherein the sensitivity correction function is step-like. (3) The ultrasonic diagnostic apparatus according to claim 1, wherein the sensitivity correction function is obtained by further integrating a step-like function and converting it into a slope-like function. (4) The ultrasonic diagnostic apparatus according to claim 2 or 3, characterized in that the output of an 8TC function generator is further synthesized as the sensitivity correction function.