JP2560017B2 - Ultrasonic diagnostic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] The present invention is an ultrasonic diagnostic apparatus that transmits ultrasonic waves to a subject, receives a high frequency (RF) reflected echo signal, and displays acoustic characteristic values. Is added in synchronization with the transmission signal a predetermined number of times to improve the S / N ratio of the reception echo signal attenuated in the specific layer of the subject and the accuracy of the acoustic characteristic value.

[Industrial applications]

The present invention relates to an ultrasonic diagnostic apparatus, and in particular, an ultrasonic diagnostic apparatus for obtaining a reflected echo signal with a good S / N ratio when imaging the acoustic characteristics of a subject with an ultrasonic TC (tissue characteristic) diagnostic apparatus. Regarding the device.

[Conventional technology]

FIG. 7 is a system diagram of a conventional ultrasonic diagnostic apparatus, and FIG. 8 is a conventional timing signal and reflected echo signal waveform diagram.

In FIG. 7, the subject 1 is a living body such as a human body and has internal tissues.
When 13 acoustic characteristic values are displayed on the display means 9 such as a cathode ray tube, it is analyzed that the acoustic characteristic values of healthy tissue and tumor tissue are different, and the analysis result is imaged to detect abnormalities in the tissue. In order to determine the presence or absence and its position, for example, a linear electronic scanning probe 2 using a transducer group in which thousands of strip-shaped vibrating elements are arranged laterally adjacent to each other
Contact with. The timing generation circuit 5 generates the transmission timing signal 14 shown in FIG. 8A to drive the transmission amplifier 4. Further, the electronic switch 3 preliminarily selects an arbitrary combination of transducer groups of the probe 2, and the output of the transmission amplifier 4 pulse-drives the probe 2. The ultrasonic waves emitted from the probe 2 are reflected by the internal tissue 13 in the subject 1,
It is returned to the probe 2 again. The ultrasonic wave reflection echo signal (hereinafter referred to as RF signal) 15 generated in the probe 2 is amplified by the reception amplifier 6 and input to the acoustic characteristic analysis circuit 7. The acoustic characteristic analysis circuit 7 obtains the acoustic characteristic value of the internal tissue 13 with respect to the depth from the RF signal. This value is written in the storage circuit 8 including a frame memory or the like. The data written in the memory circuit 8 is added to the reading and displaying means 9 and the ultrasonic beam 12
The above acoustic characteristic values are displayed on the scanning line 10 on the display means 9.

A two-dimensional acoustic characteristic image 11 corresponding to the internal tissue 13 is obtained by switching the electronic switch 3 to scan the combination of the probes 2 in the direction orthogonal to the emission direction of the ultrasonic beam 12.

[Problems to be solved by the invention]

The RF signal 15 obtained by the ultrasonic diagnostic apparatus described above is shown in FIG. 8B.
As shown in the waveform diagram, the amplitude decreases from the surface of the subject 1 toward the deep layer. This is because the ultrasonic beam 12 is attenuated in the internal tissue.

On the other hand, the thermal noise generated at the input of the probe 2, the electronic switch 3, and the receiving amplifier 6 is constant regardless of the radiation depth of the ultrasonic beam. For this reason, the S / N ratio of the RF signal reflected from the internal tissue in the deep part is deteriorated, and the noise is added to the image as it goes downward on the screen of the display unit 9, and the image quality cannot be said to be clear. Will result in a bad image. or,
The analysis is also entrusted to the experience and judgment of the doctor, so there was a problem that caused a diagnosis.

The present invention has been made based on the above-mentioned drawbacks, and an object of the present invention is to obtain an ultrasonic diagnostic apparatus capable of improving the image quality displayed on the display means 9 and accurately estimating the acoustic characteristic value.

[Means for solving problems]

The ultrasonic diagnostic apparatus of the present invention transmits ultrasonic waves to the subject 1, receives reflected echo signals, calculates and displays acoustic characteristic values, and arranges a plurality of transducers in an array. The reflection echo signal is added at the same scanning position of the scanning probe in synchronization with the transmission signal a predetermined number of times, and the addition of the reflection echo signal is performed while avoiding a period in which the reflection echo signal greatly changes. It was done like this.

[Operation] In the present invention, the RF signals are added in synchronization with the transmission timing of the ultrasonic beam, for example, when N times addition is performed,
RF signal component becomes N times and noise component Therefore, the S / N ratio is improved and the image quality of the image is improved.
Further, since the reflected echo signals are added while avoiding the period in which the reflected echo signals greatly change, noise is always efficiently removed and a good image is always obtained.

〔Example〕

An embodiment of the ultrasonic diagnostic apparatus of the present invention will be described below in detail with reference to FIGS.

FIG. 1 is a system diagram of an ultrasonic diagnostic apparatus of the present invention, and FIGS. 2 and 3 are waveform explanatory diagrams of FIG.

In FIG. 1, parts corresponding to those in FIG. 7 are designated by the same reference numerals, and redundant description will be omitted.

In FIG. 1, the output of the receiving amplifier 6 is applied to the synchronous adding circuit 16
To the acoustic characteristic analysis circuit 7
To be supplied. Other configurations are the same as in FIG. 7. The operation in this configuration will be described. The transmission pulse from the timing generation circuit 5 is emitted to the subject 1 via the transmission amplifier 4, the electronic switch 3, and the probe 2. When the electronic switch 3 is selected and scanned along the array of the probe 2, the transmission pulse applied to one or a set of the vibrating elements of the probe 2 is not switched and the electronic switch 3 is not switched.
As shown in FIG. 3, when transmission is performed several times in synchronization with the transmission timing pulse 14, one scanning line 1 is sent every time as shown in FIG. 3B.
The same RF signal 15 is obtained for.

On the other hand, thermal noise generated in the receiving amplifier 6, the electronic switch 3, the probe 2, etc. is generated regardless of the transmission timing.
In order to eliminate such thermal noise, the RF signals may be added in synchronization with the timing of transmitting the transmission pulse, and the synchronous addition is performed for the first scanning line to the nth scanning line as shown in FIG. 2A. If it is repeated N times, the signal component is multiplied by N, but the noise component is The S / N ratio is It gets better each time. When N = 2 ^M , 3 MdB and S / N ratio are improved. Now, as shown in FIG. 2A, while the transmission is repeated N times and transmitted to the subject 1, synchronous addition is performed so that the RF signal 15 is obtained on the same scanning line (scanning line 1), and finally the addition output 1
Output twice. Next, the operation is switched to the second scanning line (scanning line 2) and the above operation is repeated.

FIG. 4 is a system diagram showing the details of the synchronous adder circuit 16 shown in FIG. 1. In FIG. 4, T ₁ is an input terminal and the RF signal from the reception amplifier 6 is an analog-digital conversion circuit (A / D). ) 18
Is digitally converted by, and is added to the adder 19 and the output of the adder 19 is stored in the memory 21. 20 is a register. still,
T ₅ is an output terminal connected to the acoustic characteristic analysis circuit 7.
T _{2 to} T ₄ indicate control terminals. First, to supply clear signal 22a shown in FIG. 5 A 'in synchronization with the first scan line switching timing pulse shown in FIG. 5 A to the control terminal T _2, to clear the register 20, shown in FIG. 5 B First transmission timing pulse
In synchronism with 14a, the RF signal is added to the A / D 18, digitally converted, and supplied to the memory 21 through the adder 19. In the memory 21, writing is performed by the write pulse of FIG. 5C according to the memory address shown in FIG. 5D applied to the control terminal T ₃ . Next, in synchronization with the second transmission timing pulse 14b, an RF signal similar to the first RF signal is added to the A / D 18, digitally converted and added to the adder 19. At this time, since the data written in the memory 21 by the first transmission timing pulse 14a is read by the read pulse applied to the control terminal T ₄ and stored in the register 20, the output of the register 20 is supplied to the adder 19. , And the RF signal acquired at the second timing pulse, and the result is stored in the memory 21 again. By performing such an operation N times within one scanning line, that is, within one horizontal scanning period, the n-th transmission timing pulse is synchronously added.
Since the next second -th scan line register 20 joined by the second clear signal 22b to the control terminal T ₂ are cleared it may be performed similar to that described above synchronous addition. The final addition output after the synchronous addition within each scanning period is output to the acoustic characteristic analysis circuit 7 once for one scanning line through the output terminal T ₅ .

The electrocardiograph 17 shown in FIG. 1 is supplied to the timing generation circuit 5 for the following reason.

In order to obtain the same RF signal, for example, the liver inside the living body, a large number of ultrasonic beams were captured within one scanning line and compared with the waveform of the electrocardiogram. From the S wave to the T wave of the electrocardiographic waveform shown in FIG. We found that during the systole of the heart, the RF signal changed significantly with each transmission of the ultrasonic beam.

Therefore, the electrocardiographic waveform is monitored by the electrocardiograph 17, the synchronous addition interruption timing pulse 23 is generated between the S wave and the T wave as shown in FIG. 6B, and is supplied to the pulse generation circuit 5. Based on this pulse, the pulse generating circuit 5 causes the transmission timing pulse 14 and the write / read pulse W, R to be generated and stopped as shown in FIGS. 6D and 6E. 6C shows a scanning line switching timing pulse, and FIG. 6C shows a clear signal synchronized with this timing pulse.

〔The invention's effect〕

Since the present invention is configured and operated as described above, it is possible to improve the S / N ratio of ultrasonic RF waves, and as a result, it is possible to accurately estimate the acoustic characteristic value, so that a high-quality image is obtained and misdiagnosis is reduced. It has characteristics.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of the ultrasonic diagnostic apparatus of the present invention, FIGS. 2A and 2B and FIGS. 3A and 3B are timing waveform diagrams for explaining synchronous addition, and FIG. 4 is synchronous. A system diagram showing details of the adder circuit, FIG. 5 is a timing waveform diagram of FIG. 4, FIG. 6 is an electrocardiographic waveform diagram and a timing waveform diagram, and FIG. 7 is a system diagram of a conventional ultrasonic diagnostic apparatus. 7A and 7B are waveform explanatory diagrams of FIG. 1 ... Subject, 2 ... probe, 3 ... electronic switch, 4 ... transmission amplifier, 5 ... timing generation circuit, 6 ... reception amplifier, 7 ... acoustic characteristic analysis circuit, 8 ... memory Circuit, 9 ... Display means, 16 ... Synchronous addition circuit, 17 ... Electrocardiograph, 18 ... A / D, 19 ... Adder, 20 ... Register, 21 ... Memory.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Isamu Yamada 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Fujitsu Limited (72) Inventor Shijo Menjo Castle, 1015, Kamedotachu, Nakahara-ku, Kawasaki, Ltd. (72) Invention Osamu Hayashi 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Fujitsu Limited (72) Inventor Hirohide Miwa 1015 Kamikotanaka, Nakahara-ku, Kawasaki-shi, Fujitsu Limited (56) Reference JP 61-268236 (JP, A) ) JP-A-61-226023 (JP, A) JP-A-56-18853 (JP, A)

Claims (2)

(57) [Claims] 1. An ultrasonic diagnostic apparatus for transmitting ultrasonic waves to a subject, receiving reflected echo signals from the subject, calculating acoustic characteristic values of the subject, and displaying the acoustic characteristic values. In, in synchronization with the timing of the transmission of the ultrasonic wave, and avoiding the period of a specific portion of the electrocardiogram or electrocardiographic waveform that greatly changes the reflected echo signal obtained for each transmission of the ultrasonic wave, the reflected echo signal An ultrasonic diagnostic apparatus characterized by adding a predetermined number of times. 2. The ultrasonic diagnostic apparatus according to claim 1, wherein the specific portion of the electrocardiographic or electrocardiographic waveform is a period from S wave to T wave.