JP2001104308A - Ultrasonograph - Google Patents

Abstract

PROBLEM TO BE SOLVED: To more clearly extract desired Doppler sound information by applying gain control to the Doppler sound information in accordance with its frequency. SOLUTION: This device is provided with a phase detecting circuit 13, a frequency analyzer 14 to analyze the frequency of a phase-detected signal, a normal/inverse separation part 17 to separate it into two types of sound information of a blood current going toward an ultrasonic probe and a blood current going from it based on the frequency of the phase-detected signal, and a gain control part 18 to control the level of the sound information using output of the frequency analyzer 14. From this blood current signal of micro flow quantity, sound like that of a blood current of a high flow speed can be clearly extracted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to an ultrasonic Doppler blood flow meter capable of outputting a Doppler signal (Doppler shift component) of an ultrasonic echo as audio information.

[0002]

2. Description of the Related Art In an ultrasonic Doppler blood flow meter, which is widely used in diagnosis of a living body circulatory organ, etc., as well as Doppler spectrum information displayed as an image with the progress of the diagnosis technology, the Doppler voice information is more important. Element. As an ultrasonic Doppler blood flow meter capable of acquiring Doppler audio information together with Doppler spectrum information, for example, there has been one disclosed in Japanese Patent Application Laid-Open No. 7-79976. The basic principle of the ultrasonic Doppler blood flow meter disclosed in the above publication will be described below with reference to FIG.

The ultrasonic Doppler blood flow meter includes a Doppler detector (phase detection circuit) 31 for detecting a phase of a received signal obtained through an ultrasonic probe (not shown) and an output of a Doppler detector 32. Multipliers 32 and 33 for multiplying the output of a digital filter 34 described later, an amplifier 37 for amplifying the outputs of the multipliers 32 and 33, and an A / D converter for digitizing the output of the amplifier 37.
38, a frequency analysis unit 39 for analyzing the frequency of the output data of the A / D converter 38, a D / A converter 40 for converting the output data of the A / D converter 38 into an analog signal, and a D / A converter 40. A low-pass filter 41 for removing an aliasing signal of the output, and a forward / reverse separation unit 42 for separating the blood flow coming toward the ultrasonic probe and the blood flow going away from the output of the low-pass filter 41 as audio information, A speaker 43 for outputting audio information,
An absolute value calculator 36 for calculating the amplitude of the output data of the A / D converter 38, a gain calculator 35 for calculating a gain to be controlled from the absolute value, and a digital filter for filter-controlling the output of the gain calculator 35 And 34.

In the ultrasonic Doppler blood flow meter configured as described above, the driving pulse generated by the transmission scanning circuit (not shown) is applied to the ultrasonic transducer of the ultrasonic probe, and It is converted and transmitted to the subject. Ultrasonic waves (ultrasonic echoes) reflected from the subject are converted into electric signals by the ultrasonic transducer of the ultrasonic probe and sent to a receiving scanning circuit (not shown).

After the received signal is processed by the reception scanning circuit, the signal is subjected to detection processing in a Doppler detection unit 31, and the obtained R (real part) signal and I (imaginary part) signal are converted into a frequency analysis unit 39. The frequency of blood flow in the subject is determined by frequency analysis in the
(rter) unit (not shown) performs scan conversion and displays an image on a monitor.

The signal digitized by the A / D converter 38 passes through a D / A converter 40 and a low-pass filter 41, and is separated by a forward / reverse separating unit 42 into a blood flow coming toward the ultrasonic probe. Separated into two audio information of the blood flow going away,
The sound is output from the speaker 43 as sound.

Further, in accordance with the amplitude of the output data of the A / D converter 38, the absolute value calculation unit 36 and the gain calculation unit 35 calculate the gain in accordance with the magnitude of the amplitude. A multiplier 32 provided after the section 31;
33 performs data compression. Thus, when the output signal level from the Doppler detector 31 is low, compression is not performed.When the output signal level is high, compression is performed. Create blood flow velocity image and output accurate blood flow velocity.

That is, in the above conventional example, the amplitude of the blood flow information obtained by the phase detection is uniquely subjected to gain control processing without depending on the Doppler frequency, and is output as audio information.

[0009]

However, in the above-described conventional ultrasonic Doppler blood flow meter, gain control cannot be performed in accordance with the frequency of Doppler audio information, so that a high-speed blood flow with a small flow rate or the like cannot be performed. The extraction was not clear, and it was not possible to obtain Doppler audio information according to the purpose of diagnosis or the purpose of diagnosis.

There is also a method of performing LOG (logarithmic) compression for gain control. However, there is a problem that a low frequency with good audibility of the human body is emphasized and a high frequency sound is hard to hear.

SUMMARY OF THE INVENTION The present invention has been made to overcome the above-mentioned conventional drawbacks, and obtains desired Doppler audio information by performing gain control on Doppler audio information in accordance with the frequency. It is an object of the present invention to provide an ultrasonic diagnostic apparatus that enables reliable diagnosis.

[0012]

According to the ultrasonic diagnostic apparatus of the present invention, an ultrasonic echo transmitted from an ultrasonic probe into a living body, reflected in the living body, and received by the ultrasonic probe is provided. Phase detection means for phase-detecting the Doppler signal, frequency analysis means for analyzing the frequency of the phase-detected signal, and blood flow coming from the frequency of the phase-detected signal toward the ultrasonic probe. It has a configuration comprising: a forward / reverse separating unit that separates two pieces of voice information of a blood flow that goes away, and a gain control unit that controls the level of the voice information using the output of the frequency analysis unit. With this configuration, it is possible to perform gain control of audio information in accordance with the frequency and obtain desired Doppler audio information corresponding to a diagnostic use or a diagnostic purpose.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to FIGS.

FIG. 1 is a block diagram showing a configuration of an ultrasonic Doppler blood flow meter according to a first embodiment of the present invention.

In the ultrasonic Doppler blood flow meter according to the first embodiment of the present invention, the gain of the Doppler audio information is controlled in accordance with the Doppler frequency shift of the ultrasonic echo, so that a high-speed blood flow with a minute flow rate is obtained. Etc. can be clearly extracted.

As shown in FIG. 1, the ultrasonic Doppler blood flow meter transmits an ultrasonic pulse to an object, receives an ultrasonic wave reflected from the object, and converts the ultrasonic wave into an electric signal. Ten
A transmission scanning circuit 11 for scanning an ultrasonic beam transmitted from the ultrasonic probe 10, a reception scanning circuit 12 for scanning an ultrasonic wave received by the ultrasonic probe 10, A phase detection circuit 13 for detecting a Doppler signal by detecting a phase of an output signal of the scanning circuit 12, a frequency analyzer 14 for analyzing a frequency of an output of the phase detection circuit 13, and an image for displaying an output of the frequency analyzer 14. A DSC unit 15 for converting the data into data, and a DSC unit 15
Using a monitor 16 that displays the output of the ultrasonic probe and an output of the phase detection circuit 13, the audio information is separated into a blood flow (forward direction) toward the ultrasonic probe and a blood flow that goes away (reverse direction). Separation unit 17, gain control unit 18 that controls the gain of the output of forward / reverse separation unit 17 using information from frequency analyzer 14, and left and right speakers 1 that output the output of gain control unit 18 as audio.
9 and 20 are provided.

Here, the DSC unit 15 generates image data corresponding to a blood flow velocity image indicating, for example, time on the horizontal axis and frequency shift on the vertical axis (+ in the forward direction and − in the reverse direction). Also,
The left and right speakers 19 and 20 output the blood flow velocity sound from the right speaker in the forward direction and the left speaker in the reverse direction, for example.

In the ultrasonic Doppler blood flow meter configured as described above, the drive pulse generated by the transmission scanning circuit 11 is applied to the ultrasonic transducer of the ultrasonic probe 10, converted into ultrasonic waves, and received. Transmitted to the specimen. Ultrasonic waves reflected from the subject are converted into electric signals by the ultrasonic transducer of the ultrasonic probe 10 and sent to the reception scanning circuit 12. Then, after the reception processing is performed by the reception scanning circuit, the phase detection circuit 13 performs detection processing. The R signal and the I signal obtained by this process are subjected to frequency analysis in the frequency analyzer 14 to obtain the moving speed of the blood flow in the subject, and the DSC unit
At 15, scan conversion is performed, and an image is displayed on the monitor 16.

The output of the phase detection circuit 13 is separated by a forward / reverse separation unit 17 into two pieces of audio information of a blood flow coming to the ultrasonic probe 10 and a blood flow going away, and a gain control unit 18
After receiving the gain control in accordance with the output of the frequency analyzer 14, the audio is output from the speakers 19 and 20 as sound.

Next, the gain control in the gain control section 18 will be described in detail with reference to FIGS.

In the gain control section 18, the amplitude as shown in FIG.
in, and when a signal whose frequency is f1A in the period A and f1B in the period B is input, the gain shown in the following equation is obtained according to the high-frequency f1B portion and the low-frequency f1A portion. Perform control. V1outA = K1 × V1in × | f1A | V1outB = K2 × V1in × | f1B |

In these equations, V1in is the gain control unit 18
V1outA is the amplitude of the gain control unit in period A
The amplitude of the output signal from the gain control unit 18, f1A is the frequency of the signal input to the gain control unit 18 in the period A, V1outB is the amplitude of the output signal from the gain control unit 18 in the period B, and f1B is the period B
In the frequency of the signal input to the gain control unit 18, K1,
K2 indicates a coefficient. Here, if | f1A | <| f1B |, K1
<K2, and when | f1A | ≧ | f1B |, K1 ≧ K2. As described above, the gain can be controlled to be larger as the frequency analyzed by the frequency analyzer 14 becomes higher. Therefore, when attention is paid to a clinically fast blood flow, a voice with a fast flow velocity can be emphasized and clearly extracted.

FIG. 3 shows gain control in the case where the frequencies of the forward and reverse output signals from the forward / reverse separating unit 17 to the gain control unit 18 are different from each other. Input # 1 of gain control unit 18
A signal having an amplitude V2inA and a frequency f2A is input to an input # 2.
When a signal of B and frequency f2B is input, gain control shown in the following equation is performed. V2outA = K3 x V2inA x | f2A | V2outB = K4 x V2inB x | f2B |

In these equations, V2inA and V2inB are the amplitude of the input signal of the gain control unit 18, V2outA and V2outB are the amplitude of the output signal from the gain control unit 18, f2A is the frequency of the signal of the input # 1, and f2B is the input. The frequency of the signal of # 2, K3 and K4, indicate coefficients. Here, when | f2A | <| f2B |, K3 <K4,
When | f2A | ≧ | f2B |, K3 ≧ K4. in this way,
The higher the frequency analyzed by the frequency analyzer 14, the larger the gain can be controlled.

Although FIGS. 2 and 3 show an example in which the gain is controlled to be higher as the frequency is higher, it is of course possible to control the gain to be higher as the frequency is lower.
By controlling in this way, when a slow blood flow is clinically noticed, it is possible to emphasize a voice with a slow flow velocity and extract it clearly.

As described above, in the first embodiment of the present invention, since the gain control of Doppler audio information is performed in accordance with the Doppler frequency shift of the ultrasonic echo, a high-speed blood flow with a small flow rate can be clearly identified. And output as an audible sound.

FIG. 4 is a block diagram showing a configuration of an ultrasonic Doppler blood flow meter according to a second embodiment of the present invention.

The ultrasonic Doppler blood flow meter according to the second embodiment of the present invention performs the amplitude control of the Doppler frequency shift component when performing the gain control of the Doppler audio information according to the Doppler frequency shift of the ultrasonic echo. By using the gain control according to, the high-speed blood flow with a small flow rate can be more clearly extracted.

In FIG. 4, the same components as those in FIG. 1 or corresponding components are denoted by the same reference numerals as those used in FIG. 1, and the description thereof is omitted.

The ultrasonic Doppler blood flow meter according to the second embodiment of the present invention detects the amplitude of the output signal of the forward / reverse separation unit 17 as compared with the ultrasonic Doppler blood flow meter according to the first embodiment. An amplitude detector 21 is added, and the output of the amplitude detector 21 is also used as a gain controller.
It is configured to be used for gain control in 18. The amplitude detector 21 calculates the absolute value of the Doppler signal by calculating the square root of the sum of squares of the forward and backward audio information separated by the forward / backward separator 17.

The absolute value of the Doppler signal indicates the amplitude of the output signal of the forward / reverse separation unit 17, is input to the gain control unit 18, and is used for gain control as V1in, V2in, and the like in the gain control expression.

The basic operation of the ultrasonic Doppler blood flow meter configured as described above is the same as that of the first embodiment. In the present embodiment, the amplitude of the output signal from the forward / inverse conversion unit 17 is further detected by the amplitude detection unit 21, and the coefficients K1, K2, K3, and K4 are corrected by the gain control unit 18. By this correction, a signal with a large amplitude is compressed and a small signal is amplified, and a more effective action can be obtained in gain control according to the frequency.

As described above, in the second embodiment of the present invention, when performing the gain control of the Doppler audio information according to the Doppler frequency shift of the ultrasonic echo, the amplitude control of the Doppler frequency shift component is performed. Since the gain control is also used, a high-speed blood flow with a minute flow rate can be more clearly extracted and output as an audible sound.

[0034]

As described above, according to the present invention,
By performing gain control of Doppler audio information according to the Doppler frequency shift of ultrasonic echo, if clinically fast blood flow is focused on, emphasize high frequency, that is, voice with high flow velocity and extract it clearly. To provide an ultrasonic diagnostic apparatus that has an excellent effect of emphasizing low-frequency voice, that is, a voice with a low flow velocity, and clearly extracting the voice when a slow blood flow is clinically noticed. Can be.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an ultrasonic Doppler blood flow meter according to a first embodiment of the present invention;

FIG. 2 is a diagram for explaining an example of gain control in the ultrasonic Doppler blood flow meter of FIG. 1;

FIG. 3 is a view for explaining another example of gain control in the ultrasonic Doppler blood flow meter of FIG. 1;

FIG. 4 is a block diagram showing a configuration of an ultrasonic Doppler blood flow meter according to a second embodiment of the present invention;

FIG. 5 is a block diagram showing a configuration of a conventional ultrasonic Doppler blood flow meter.

[Explanation of symbols]

 10 Ultrasonic probe 11 Transmission scanning circuit 12 Reception scanning circuit 13 Phase detection circuit 14 Frequency analyzer 15 DSC section 16 Monitor 17 Forward / reverse separation section 18 Gain control section 19, 20 Speaker 21 Amplitude detection section

Continued on the front page (72) Inventor Shigeyoshi Kadokura 4-3-1 Tsunashimahigashi, Kohoku-ku, Yokohama-shi, Kanagawa F-term (reference) in Matsushita Communication Industrial Co., Ltd. 4C301 DD02 DD04 EE13 HH54 JB17

Claims (2)

[Claims] 1. A phase detector for phase-detecting a Doppler signal of an ultrasonic echo transmitted from an ultrasonic probe into a living body, reflected in the living body, and received by the ultrasonic probe,
Frequency analyzing means for analyzing the frequency of the phase-detected signal, and separating the two voice information from the frequency of the phase-detected signal into two pieces of blood information of a blood flow coming toward the ultrasonic probe and a blood flow going away. An ultrasonic diagnostic apparatus comprising: a separating unit; and a gain control unit that controls a level of the audio information using an output of the frequency analyzing unit. 2. An apparatus according to claim 1, further comprising: an amplitude detector for detecting an amplitude of an output signal of said forward / reverse separator, wherein said gain controller uses a gain control in accordance with an output of said amplitude detector. An ultrasonic diagnostic apparatus as described in the above.