JPS62243541A - 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] [Industrial Field of Application] The present invention relates to an ultrasonic diagnostic apparatus, particularly an ultrasonic diagnostic apparatus for detecting biological tissue within a subject.
! The present invention relates to an ultrasonic diagnostic apparatus that determines I quality using the propagation attenuation constant of ultrasonic waves and displays this as a two-dimensional image.

[Prior Art] Ultrasonic diagnostic devices that non-invasively display images of affected areas and other living tissues within a subject are well known, and include transmitting ultrasound beams toward desired living tissues and reflecting them from the living tissues. It is possible to receive reflected echoes and display a desired cross section within the subject as a B-mode image or the like based on the electrically received signal.

According to such an ultrasonic diagnostic apparatus, the state of internal tissues can be observed safely and in real time without adversely affecting the subject, which greatly contributes to the diagnostic effect.

[Problems to be Solved by the Invention] However, conventional ultrasonic diagnostic equipment only displays images of the shape of one organ on a biological cross-section inside a subject, and does not display the characteristics of biological tissues. (j) There was a problem that information could not be obtained from the ultrasound images.

As is well known, each of the 18 types of biological tissues within a subject has different attenuation constants for ultrasound waves, and between normal tissue and tumorous tissue, the quality of the tissue can be determined by determining these attenuation constants. Conventionally, there has been no device that can visually display such qualitative judgments in real time based on the propagation attenuation constant of ultrasonic waves.

The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to provide an improvement in which propagation attenuation constant information contained in an ultrasonic reception signal can be extracted in real time and displayed as a two-dimensional image as it is. The purpose of the present invention is to provide an ultrasonic diagnostic device that is

[Means for Solving the Problems] In order to achieve the above object, the present invention first smoothes the received signal of reflected echo = by a low-pass filter, and then applies the slope of this smoothed signal to a differentiating circuit. This is obtained by differentiating by
Since the ultrasonic propagation attenuation constant is proportional to
It is characterized by being able to display the characteristics of the subject's biological tissue on the screen in real time by displaying it as a dimensional image.

[Embodiments] Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 1 shows a preferred embodiment of the ultrasonic diagnostic apparatus according to the present invention. The ultrasonic probe 10 is J3 in the embodiment.
It consists of a linear electronic scanning probe, and the test object 100 is
An ultrasound beam 200 is transmitted to the body to display an image of the living body LIA 102 such as the liver inside the subject 100.

A transmitting circuit 12 is provided to excite the ultrasound probe, and controls the excitation action of the ultrasound probe 10 based on a reference signal from an oscillator 14 to produce a desired linear electronically scanned ultrasound beam 200. It is transmitted into the subject 100.

The reflected echo reflected from the living tissue of the subject 100 is converted into an electrical signal by the ultrasonic probe 10, and then sent to the receiving circuit 16.
The transmitting circuit 12 applies predetermined electrical processing to this received signal in synchronization with the transmitting circuit 12, and, for example, the receiving circuit 16 performs overlapping in synchronization with linear electronic scanning and focus control during each scan. A predetermined delay control is applied to the 1f:4 signal received from each transducer of the sonic probe 10.

The output of the receiving circuit 16 is logarithmically amplified P! i18 and STC
Predetermined preprocessing is performed by the circuit 20.

In the present invention, preprocessing by the logarithmic amplifier 18 or the STC circuit 20 is not necessarily required in order to obtain the ultrasound propagation attenuation constant from the ultrasound reception signal by signal differentiation. In order to display images of living body III within 100 in 8 modes, and to superimpose or display two images side by side on the same screen, ultrasonic propagation attenuation constant images showing the characteristics of each living tissue are further superimposed on this image.
The received signal of the receiving circuit 16 is subjected to both logarithmic amplification and STC amplification preprocessing so that it can be used for both B-mode image processing and differential processing according to the present invention.

It is also possible to perform both the logarithmic amplification and the STC amplification at the same time. In the embodiment, the logarithmic amplification 318 compensates for the attenuation of the ultrasound beam in the depth direction, and the STC circuit 20 compensates for the attenuation of the ultrasound beam due to the focus and medium. Compensation for the attenuation of is performed to a predetermined value.

rWJAs mentioned above, in principle, the preprocessing is unnecessary in the present invention, but in this embodiment, at least compensation of the received signal strength by the logarithmic amplifier 18 is effective in reducing the dynamic This is practically necessary in order to keep the signal within the range, and by using the at least logarithmic amplifier 18 for compensation of the received signal strength in the depth direction, the subsequent processing of the circuit can be facilitated.

However, on the other hand, it is understood that such pretreatment has a large effect on the ultrasound propagation attenuation constant due to each biological tissue.

FIG. 2 shows the waveforms of the main parts of the processing circuit shown in FIG. 1, and the output of the receiving circuit 16 is shown as a waveform 301 in FIG. The strength of the received signal decreases, and from the living tissue 102 such as the liver inside the subject 100, a signal with a higher reflected echo strength than other tissues is transmitted from the living tissue 102 such as the liver inside the subject 100.
It is understood that as the depth Z further increases, the reception strength decreases logarithmically.

The waveform 301 is compensated as shown by the waveform 302 by the logarithmic amplifier 18 and the STC circuit 20 described above,
Although it is not necessarily clear from the waveform in FIG. 2, in reality, the logarithmic decrease in waveform 301 is more severe than shown in the figure.
This can be compensated for into a relatively gentle waveform as shown by the waveform 302. However, as described above, according to such preprocessing, an artificial It is clear that adding additional data processing makes it difficult to obtain the correct attenuation constant.

In this example, in order to balance the need for such preprocessing with the need to accurately determine the attenuation constant, a method is adopted in which the ultrasonic propagation attenuation constant is calculated as a relative value rather than an absolute value. However, a correction circuit 22 is provided for this relative correction.

The calculation of the relative attenuation constant in the embodiment is performed by correcting the preprocessed signal 302 using phantom data measured in advance on a reference phantom, and the phantom data is stored in the memory 24 in advance, and the correction circuit 22 receives this phantom data and the preprocessed signal 302, and performs a desired correction calculation.

The phantom data is uniform using the ultrasonic circuit configured in advance as shown in the figure! l! An ultrasonic beam is transmitted to a quality reference phantom, the attenuation constant at this time is measured by transmission reflection power, etc., and phantom data for the reference phantom in the depth direction is stored.

Therefore, this phantom data includes gain change data according to distance that has been subjected to the preprocessing in the depth direction, and the correction circuit 22 corrects the received signal 302 in the depth direction using the phantom data. By this,
It becomes possible to obtain the propagation attenuation constant within the living tissue as a correct relative position by excluding the influence of the gain change due to the pre-processing and the state of the ultrasound beam.

In this embodiment, the output of the correction circuit 22 in which the attenuation constant is corrected as a relative position is further supplied to a low-pass filter 26 to obtain a smoothing signal 3 from which high frequency components have been removed.
03. This smoothing by the low-pass filter 26 is essential because when determining the ultrasonic propagation attenuation constant by signal differentiation, which is a feature of the present invention, differentiation cannot be performed if high frequency components are included.

As described above, the smoothed signal 303 is differentiated in the differentiating circuit 28, which is characteristic of the present invention.
As shown by a waveform 304 in FIG. 2, the ultrasound propagation attenuation constant has different values depending on the characteristics of the living tissue.

In this embodiment, such ultrasound propagation attenuation constants are processed in real time to display the image as it appears, and at the same time, the shape of the living tissue observed using the normal ultrasound B-mode image is displayed. There is.

For this purpose, the output 302 of the 870 circuit 20 is supplied to the correction circuit 20, and the output 302 of the 870 circuit 20 is once supplied to the frame memory 30.
A reading circuit 32 reads out the image data in the frame memory 30 according to the standard television method, and mixes this shape signal with an ultrasonic propagation attenuation constant signal 304, which is the output of the differentiating circuit 28, by a mixer 34, and displays the image data. The image is displayed on the CRT 36 which is the device.

In this embodiment, it is possible to display the shape image and the propagation constant image in a superimposed manner as the same image, or it is also possible to divide one screen into two and display both in parallel.

As described above, according to this embodiment, the relative attenuation constant corrected by the reference phantom can be displayed as an image in real time, and it is possible to display not only the shape of the biological tissue but also the shape of the biological tissue.
By displaying the characteristics of 4iI as an image of the propagation attenuation constant of ultra-waves, it is extremely easy to find the altered medium caused by a tumor inside a living tissue. It becomes possible to obtain.

According to the embodiment, the ultrasound propagation attenuation constant is displayed simultaneously with the B-mode shape, but it is also possible to perform diagnosis from image data of only the attenuation constant.

[Effects of the Invention] As explained above, according to the present invention, the characteristics of biological tissue can be determined from the ultrasound propagation attenuation constant using an ultrasound beam, and this can be displayed in real time as a two-dimensional image. Therefore, it becomes possible to quickly and accurately diagnose the inside of the subject.

[Brief explanation of drawings]

FIG. 1 is a block circuit diagram showing a preferred embodiment of the ultrasonic diagnostic apparatus according to the present invention, and FIG. 2 is a waveform diagram of each part of FIG. 1. 10... Ultrasonic probe 12... Transmission circuit 16... Receiving circuit 22... Correction circuit 24... Phantom data memory 26...
Loaf? Filter 28...Differential circuit 36...Display device 100...Object 200...Ultrasonic beam

Claims (2)

[Claims] (1) a transmitting circuit that excites an ultrasound probe and transmits an ultrasound beam into the subject; a receiving circuit that is synchronously controlled with the transmitting circuit and receives reflected echoes from the subject and converts them into electrical signals; An ultrasonic diagnostic apparatus that displays an image of an affected area within a subject based on a received signal of the receiving circuit, including a low-pass filter that smoothes the output signal of the receiving circuit, and a differentiation circuit that differentiates the output of the low-pass filter, An ultrasonic diagnostic apparatus characterized in that an ultrasonic propagation attenuation constant in a biological tissue of a subject is determined for each reflection point by the differential circuit, and this is displayed as a two-dimensional image. (2) An ultrasonic diagnostic apparatus according to claim (1), wherein the receiving circuit output is corrected by a correction circuit based on phantom data.