JP3518910B2 - Ultrasound diagnostic equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a probe having a built-in ultrasonic vibrator, which vibrates the vibrator to transmit ultrasonic pulses into living tissue and echoes reflected from the living body. The present invention relates to a medical ultrasonic diagnostic apparatus for obtaining a tomographic image of a living body by receiving signals from the probe and processing the signals.

[0002]

2. Description of the Related Art In recent years, a probe having an ultrasonic vibrator is provided, which vibrates the vibrator to transmit an ultrasonic pulse into a living tissue, and an echo reflected from the living body is also probed by the probe. 2. Description of the Related Art A medical ultrasonic diagnostic apparatus that obtains a biological tomographic image by receiving a signal and then processing the signal is widely used.

In such a conventional medical ultrasonic diagnostic apparatus, when beam synthesis is performed by digital signal processing performed after receiving an ultrasonic beam (for example, imaging is performed by the aperture synthesis method), the received signal is AD. As processing before conversion, it is necessary to amplify the received signal only by the linear amplifier without performing logarithmic amplification or the like. Further, GAIN adjustment for adjusting the sensitivity of the entire image and STC adjustment for compensating for the decrease in sensitivity due to the depth of the diagnostic region are also preferably performed in the preprocessing stage in order to increase the S / N.

Therefore, conventionally, a plurality of variable gain amplifiers respectively corresponding to the GAIN and STC adjusting means are provided in a cascade connection in a preprocessing step of converting a received signal into a digital signal. That is, since a plurality of cascade-connected variable gain amplifiers are controlled independently corresponding to GAIN and STC, the amplification degree of the variable gain amplifier in the latter stage may become higher than that in the first stage. . This is not an advantageous method considering the S / N of the entire circuit. In addition, a small amount of preamplifier with fixed gain and low noise is improved in the front stage, but there is also a problem of oscillation.Therefore, a preamplifier with a very high gain is placed in front of the variable gain amplifier with a high gain connected in cascade. I can't turn it on. Therefore, the variable gain amplifier has a considerable influence on the S / N of the entire diagnostic apparatus.

Here, a conventional example will be described in detail with reference to FIGS. 7 and 8. FIG. 7 shows a variable gain amplifier 52,
This is an example in which 53 is cascade-connected in two stages, and the scanning method is omitted.

As shown in FIG. 7, the ultrasonic transducer 50 is driven by transmitting means (not shown), emits ultrasonic pulses, receives the echoes thereof, and converts them into electric signals. This received signal is transmitted to the preamplifier 51, the variable gain amplifier 52,
The signal is amplified by 53, and the signal processing circuit 54 performs detection, AD conversion,
It receives processing such as storing and reading in the image memory. Further, when performing image formation by the aperture synthesis method, the signal processing circuit 54 performs high-speed AD conversion, the received signal waveform itself is stored as digital data in the waveform memory, and additive reading is performed based on predetermined wavefront trajectory data. It Furthermore, in the case of imaging a moving object such as blood flow, an FFT operation unit for performing Fourier analysis on a received signal is provided (for example, see Japanese Patent Laid-Open No. 5-115477). The signal that has been subjected to these predetermined processes in the signal processing circuit 54 is imaged as a B-mode image on the display device 55.

The operator operates the S provided on the operation panel 56.
The TC adjusting mechanism 57 and the GAIN adjusting mechanism 58 are operated to control the gains of the variable gain amplifiers 52 and 53, respectively.
Reference numeral 59 is an STC control circuit, and reference numeral 60 is a GAIN control circuit, which controls the variable gain amplifiers 52 and 53 based on the information from the STC adjustment mechanism 57 and the GAIN adjustment mechanism 58 and the transmission timing (m) of the control circuit 61. The control voltages (k) and (l) are output respectively.

FIG. 8 shows control voltages (k) and (l) at this time.
And the transmission timing (m). The STC control voltage (k) is changed so that the amplification degree of the variable gain amplifier 52 continuously increases during the reception period in order to compensate for the attenuation of the echo signal from a deep place. Further, the GAIN control voltage (l) is constant. Here, the variable gain amplifiers 52 and 53 are assumed to have a higher amplification degree as the control voltage increases. Amax and Bmax in the figure are ST
It is a voltage value that gives the maximum amplification of C and GAIN.

At time t ', the STC control voltage (k) is not the maximum, and the GAIN control voltage (l) is large to some extent. That is, it is advantageous to prioritize the amplification degree of the variable gain amplifier 52 in the preceding stage and allocate it to a higher value in consideration of the overall S / N.
This is actually not the case because 2 and 53 are controlled independently.

[0010]

That is, in an ultrasonic diagnostic apparatus having a conventional STC / GAIN adjusting mechanism using a variable gain amplifier, a plurality of variable gains independently controlled corresponding to STC and GAIN are provided. The amplifiers are connected in cascade. Therefore, the gain of the variable gain amplifier in the latter stage may be higher than that of the variable gain amplifier in the last stage, and in view of the SN ratio of the entire diagnostic apparatus, it may not be said that the gain distribution is optimum.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an ultrasonic diagnostic apparatus which automatically realizes optimum gain distribution and has a good S / N.

[0012]

An ultrasonic diagnostic apparatus according to claim 1 of the present invention transmits an ultrasonic pulse into a living body and receives an echo signal reflected from the living body,
A medical ultrasonic diagnostic apparatus for obtaining a tomographic image of a living body based on the echo signal, comprising a plurality of variable gain amplifiers for amplifying the echo signals, and a GAIN amplification degree for adjusting detection sensitivity of the plurality of variable gain amplifiers. The GAIN setting means for setting, the STC setting means for setting the STC amplification degree for correcting the difference in attenuation depending on the depth of reflection of the ultrasonic pulse, and a preprogrammed microcomputer, and the GAIN setting means and the Based on the gains of the GAIN and STC set by the STC setting means, among the variable gain amplifiers,
The ultrasonic diagnostic apparatus according to claim 2 further comprises: a gain distribution unit that automatically sets a gain distribution so that the amplification degree of the variable gain amplifier in the previous stage is preferentially increased. , Sends an ultrasonic pulse into the living body, and also receives the echo signal reflected from the living body,
A medical ultrasonic diagnostic apparatus for obtaining a tomographic image of a living body based on the echo signal, comprising a plurality of variable gain amplifiers for amplifying the echo signals, and a GAIN amplification degree for adjusting detection sensitivity of the plurality of variable gain amplifiers. The GAIN setting means for setting, the STC setting means for setting the STC amplification degree for correcting the difference in attenuation due to the depth of reflection of the ultrasonic pulse, and the analog arithmetic circuit, and the GAIN setting means and the STC setting means G set by
A gain distribution unit for automatically setting a gain distribution so that the amplification level of the variable gain amplifier in the preceding stage of the variable gain amplifiers is preferentially increased based on the amplification levels of AIN and STC. The ultrasonic diagnostic apparatus according to claim 3 of the present invention transmits an ultrasonic pulse into a living body, receives an echo signal reflected from the inside of the living body, and outputs the echo signal. A medical ultrasonic diagnostic apparatus for obtaining a tomographic image of a living body based on a linear amplifier, comprising a plurality of variable gain amplifiers for amplifying the echo signals, and a GAIN amplifier for adjusting detection sensitivity of the plurality of variable gain amplifiers. GAIN setting means for setting the degree, and STC setting means for setting the STC amplification degree for correcting the difference in attenuation due to the depth at which the ultrasonic pulse is reflected,
Based on the respective gains of the GAIN and STC set by the GAIN setting means and the STC setting means, the gain of the variable gain amplifier in the preceding stage of the variable gain amplifiers is preferentially increased. And a gain distribution means for automatically setting the gain distribution.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 relate to the first embodiment of the present invention. FIG. 1 is a block diagram showing the configuration of an ultrasonic diagnostic apparatus, and FIG. 2 is a flow chart showing the processing flow of the arithmetic circuit of FIG. .

As shown in FIG. 1, the ultrasonic diagnostic apparatus of the first embodiment includes n ultrasonic elements 1 (1-1 to 1-1-1) that irradiate an ultrasonic pulse (not shown) on an object to be observed and detect an echo.
n), the element selection circuit 2 for switching the ultrasonic element 1 (1-1 to 1-n), and the ultrasonic element 1 (1-1 to 1-n) via the element selection circuit 2. Transmit wave generation circuit 3
The transmission drive circuit 4 for transmitting the transmission pulse generated in 1., the echo from the ultrasonic element 1 (1-1 to 1-n), the preamplifier 5, the variable gain amplifiers 6 and 7 (a plurality of variable gain amplifiers), and the BPF 8. A signal processing circuit 9 input via
A display device 10 that is digitized and stored in a signal processing circuit 9, receives an ultrasonic signal synthesis process by a digital signal such as an aperture synthesis method, and is finally imaged to display an ultrasonic image, and STC and GAIN. STC adjusting circuit 11 (STC setting means) for inputting a set value for setting G and G
An AIN adjusting circuit 12 (GAIN setting means), an arithmetic circuit 13 (gain distribution means) for calculating a set amount based on STC and GAIN set values input by the STC adjusting circuit 11 and the GAIN adjusting circuit 12, and an arithmetic circuit. A control signal generation circuit 14 that controls the amplification degree of the variable gain amplifiers 6 and 7 based on the calculation result of 13 and the control circuit 15 controls the transmission wave generation circuit 3, the control signal generation circuit 14, and the signal processing circuit 9. It is supposed to be done.

In FIG. 1, the transmission pulse generated by the transmission wave generation circuit 3 is applied to the ultrasonic transducer 1 (1-1 to 1-n) via the transmission drive circuit 3 and the element selection circuit 2 to generate ultrasonic waves. The oscillator 1 generates an ultrasonic pulse. The ultrasonic pulse thus generated is radiated into the living tissue.

Next, the echo is received again by the ultrasonic transducer 1 and input to the signal processing circuit 9 through the element selection circuit 2, the preamplifier 5, the variable gain amplifiers 6 and 7, and the BPF 8. In this way, the received signal is digitized and stored in the signal processing circuit 9, is subjected to ultrasonic wave synthesizing processing of a digital signal such as an aperture synthesizing method, and is finally imaged and displayed on the display device 10.

Here, the operator operates the STC adjusting circuit 11, G
When the AIN adjusting circuit 12 is operated and set, the set value is calculated by the calculating circuit 13, and the control signal generating circuit 14 controls the amplification degree of the variable gain amplifiers 6 and 7 based on the result. The arithmetic circuit 13 is provided with the input STC and GA.
Based on the set value of IN, the gains of the variable gain amplifiers 6 and 7 are set so that the gain of the variable gain amplifier 6 is as large as possible.

FIG. 2 is a flow chart of the calculation executed by the calculation circuit 13. In the arithmetic circuit 13, step S
Set the STC and GAIN setting values to 1, A [dB] and B, respectively.
When [dB] is set, first, in step S2, the sum C = A + B
Then, in step S3, it is determined whether or not C-Amax is larger than 0 dB. If C-Amax is larger than 0 dB, the amplification degree of the variable gain amplifier 6 in the preceding stage is maximized in step S4, and the remaining C-Amax is set. It is distributed as the amplification degree of the second-stage amplifier 7. Then, in step S6, A '= Amax, B'
= C-Amax, the values of A'and B'are set in the variable gain amplifier 6 in the front stage and the variable gain amplifier 7 in the rear stage, respectively.

If C-Amax is 0 dB or less, the total amplification degree of A and B is smaller than the maximum amplification degree of the variable gain amplifier 6 in step S5. I decided to amplify it. Then, in step S6, A '= A + B, B' = 0 dB,
The values of A'and B'are set to the variable gain amplifier 6 in the preceding stage,
The variable gain amplifier 7 in the latter stage is set.

The above calculation operates in real time with respect to the STC and GAIN settings. The arithmetic circuit 13 may be realized by using a microcomputer or a digital I
You may use the circuit comprised by C etc.

Therefore, according to the ultrasonic diagnostic apparatus of this embodiment, the optimum gain distribution can be automatically realized and the S / N can be improved, and at the same time, the arithmetic circuit 13 having the programmable gain distribution means can be used for algorithm calculation. It has the feature that it can be changed easily.

Next, a second embodiment will be described. 3 to 6 relate to a second embodiment of the present invention, FIG. 3 is a block diagram showing a configuration of a gain distribution circuit, FIG. 4 is a waveform diagram showing voltage waveforms of respective parts of the gain distribution circuit of FIG. 3, and FIG. 5 is a circuit diagram showing a specific configuration of the gain distribution circuit of FIG. 3, and FIG.
FIG. 6 is a waveform diagram showing voltage waveforms of respective parts in the circuit diagram of the gain distribution circuit shown in FIG. In the first embodiment, the gain distribution means is configured by the programmable arithmetic circuit 10, whereas in the second embodiment, the gain distribution means is configured by the gain distribution circuit which is an analog circuit, and other configurations are the same. Since it is the same as that of the first embodiment, only a different configuration will be described.

In the gain distribution circuit 20 shown in FIG. 3,
The variable gain amplifiers 6 and 7 are for amplifying the received signal in the receiving circuit of the ultrasonic diagnostic apparatus as in the first embodiment, and the amplification degree is controlled by the voltages (d) and (e).

Now, the voltage values (a) and (b) for realizing the gains of STC and GAIN set by the operator by the variable gain amplifiers 6 and 7 are the STC control voltage generation circuit 21 and GAIN control, respectively. It is assumed that the voltage is being output from the voltage generation circuit 22. The sum voltage value (c) of the voltage values (a) and (b) output from the adder 23 indicates the total amplification degree of STC and GAIN.

Then, the voltage limiter 24 is set so that the sum voltage value (c) is set to the control voltage (V _f ) that maximizes the amplification degree of the variable gain amplifier 6. As a result, the voltage value (d) output from the voltage limiter 24 becomes equal to or lower than the control voltage (V _f ) that maximizes the amplification degree of the variable gain amplifier 6. Also, after inputting the sum voltage value (c) and the voltage value (d) to the difference circuit 25 to obtain the voltage value (e) obtained by subtracting the voltage value (d) from the sum voltage value (c), this value is calculated. Variable gain amplifier 7
Input as control voltage to.

FIG. 4 shows voltage waveforms (a) to (e) of each part of the block diagram of FIG. Here, the STC control voltage (a) that changes the voltage temporally in synchronization with the transmission timing and changes the amplification degree of the variable gain amplifier is adjusted by the operator to have an arbitrary repetitive waveform. The GAIN control voltage (b) for changing the sensitivity of the entire receiving circuit is also adjusted to an arbitrary voltage (V _f ) by the operator.

Further, a concrete circuit example of the second embodiment will be described with reference to FIGS.

In FIG. 5, (f) and (g) are the STC control voltage and the GAIN control voltage, respectively, which are added by the OP amplifier 30 constituting the adder circuit 23 to obtain the sum voltage (h). Become. O that constitutes the voltage limiter 24
The P amplifier 31 is an amplitude limiting circuit, and is for suppressing the control voltage (i) applied to the variable gain amplifier 6 from becoming too large. That is, D1 and D when the amplitude is limited
The voltage generated at the second ends each V _f, when the V _z, are choosing V _f + V _z = V _z such that (variable gain amplifier 6 is a control voltage having a maximum amplification degree). By doing so, the control voltage (i) can be suppressed below the voltage at which the variable gain amplifier 6 has the maximum amplification degree.

The OP amplifier 32 constitutes the difference circuit 25,
Output (i) + (h) = (j). Since the sign of the output of the OP amplifier 31 is inverted, the OP amplifier 32 is substantially the sum voltage (h) and the amplitude-limited control voltage (i).
Will output the difference. In this way, the total gain is the same, and the gain is distributed such that the gain of the variable gain amplifier 6 in the preceding stage is preferentially higher than that of the variable gain amplifier 7 in the subsequent stage.

Therefore, according to the second embodiment, it is possible to automatically set the optimum gain distribution with an inexpensive and simple circuit and improve the S / N ratio.

[Supplementary Note] (Supplementary Note 1) The ultrasonic diagnostic apparatus according to claim 1, wherein the gain distribution means is a computing means by a microcomputer programmed in advance.

The configuration of Appendix 1 has a feature that the algorithm can be easily changed because the gain distribution means is constituted by the calculation means by the programmable microcomputer.

(Additional Item 2) The ultrasonic diagnostic apparatus according to claim 1, wherein the gain distribution means is an analog arithmetic circuit (gain distribution circuit 21 in FIG. 3).

(Additional Item 3) The analog arithmetic circuit is
An adding circuit (adding circuit 23 in FIG. 3) that adds the STC and the GAIN control voltage generated in advance, an amplitude limiting circuit (voltage limiter 24 in FIG. 3) that limits the output of the adding circuit, and the adding circuit and the amplitude. A difference circuit (difference circuit 25 in FIG. 3) that takes the difference between the output of the differential circuit and the limit circuit, and the output of the amplitude limit circuit is used as the amplification control voltage of the variable gain amplifier in the preceding stage. The ultrasonic diagnostic apparatus according to appendix 2, wherein the output is the amplification degree control voltage of the variable gain amplifier in the subsequent stage.

[0036]

As described above, according to the ultrasonic diagnostic apparatus of the present invention, the gain distribution means includes the GAIN setting means and S.
Based on the gains of GAIN and STC set by the TC setting means, the gain distribution is automatically set so that the gain of the preceding variable gain amplifier of the variable gain amplifiers is preferentially increased. There is an effect that the optimum gain distribution is automatically realized and the S / N can be improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a configuration of an ultrasonic diagnostic apparatus according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing a processing flow of the arithmetic circuit of FIG.

FIG. 3 is a block diagram showing a configuration of a gain distribution circuit according to a second embodiment of the present invention.

FIG. 4 is a waveform diagram showing voltage waveforms of respective parts of the gain distribution circuit of FIG.

5 is a circuit diagram showing a specific configuration of the gain distribution circuit of FIG.

6 is a waveform diagram showing voltage waveforms of respective parts in the circuit diagram of the gain distribution circuit shown in FIG.

FIG. 7 is a configuration diagram showing a configuration of a conventional ultrasonic diagnostic apparatus.

8 is a waveform diagram showing voltage waveforms at various parts of the ultrasonic diagnostic apparatus of FIG. 7.

[Explanation of symbols]

1 (1-1 to 1-n) ultrasonic element 2-element selection circuit 3 Transmit wave generation circuit 4 Transmission drive circuit 5 preamplifier 6, 7 Variable gain amplifier 8 BPF 9 Signal processing circuit 9 10 display device 10 11 STC adjustment circuit 12 GAIN adjustment circuit 13 Operation circuit 14 Control signal generation circuit 15 Control circuit 20 Gain distribution circuit 21 STC control voltage generator 22 GAIN control voltage generator 23 adder 24 voltage limiter 25 difference circuit 25 30, 31, 32 OP amplifier

Claims (3)

(57) [Claims] 1. An ultrasonic pulse is transmitted into a living body, and
A medical ultrasonic diagnostic apparatus that receives an echo signal reflected from the living body and obtains a tomographic image of the living body based on the echo signal, wherein the plurality of variable gain amplifiers amplify the echo signal, GA that adjusts the detection sensitivity of the variable gain amplifier
GAIN setting means for setting the IN amplification degree, STC setting means for setting the STC amplification degree for correcting the difference in attenuation due to the depth of reflection of the ultrasonic pulse, and a preprogrammed microcomputer.
In addition, the gain of the variable gain amplifier in the preceding stage of the variable gain amplifiers is preferentially increased based on the gains of the GAIN and STC set by the GAIN setting means and the STC setting means. An ultrasonic diagnostic apparatus comprising: a gain distribution unit that automatically sets a gain distribution so that 2. An ultrasonic pulse is transmitted to a living body, and
Receive the echo signal reflected from the living body,
Medical ultrasonic diagnostic equipment that obtains a tomographic image of a living body based on echo signals
A location, GA to adjust the plurality of variable gain amplifiers for amplifying the echo signals, the detection sensitivity of the plurality of variable gain amplifier
The difference between the GAIN setting means for setting the IN amplification and the attenuation due to the reflection depth of the ultrasonic pulse is compensated for.
It comprises an STC setting means for setting the correct STC amplification and an analog arithmetic circuit,
Stage and the GAI set by the STC setting means
Based on the amplification factors of N and STC, the variable gain
Of the variable gain amplifier in the previous stage
Gain distribution is automatically set so that the width is preferentially higher.
And a gain distribution means for determining
Wave diagnostic equipment. 3. An ultrasonic pulse is transmitted to a living body, and
Receive the echo signal reflected from the living body,
Medical ultrasonic diagnostic equipment that obtains a tomographic image of a living body based on echo signals
A linear amplifier and amplifies the echo signal.
A plurality of variable gain amplifiers and a GA for adjusting the detection sensitivity of the plurality of variable gain amplifiers
The difference between the GAIN setting means for setting the IN amplification and the attenuation due to the reflection depth of the ultrasonic pulse is compensated for.
The STC setting means for setting the correct STC amplification degree, the GAIN setting means and the STC setting means
Based on the specified amplification factors of GAIN and STC
In the variable gain amplifier, the
Gay so that the gain of the variable gain amplifier is preferentially increased.
Gain distribution means for automatically setting the
An ultrasonic diagnostic apparatus characterized by: