JPS6222636A - 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 [Field of Application of the Invention] The present invention is an ultrasonic diagnostic apparatus in which the velocity distribution of a moving part in a living body is improved by changing the scanning angle, scanning direction, and scanning depth of an ultrasonic pulse beam. The present invention relates to an ultrasonic diagnostic apparatus suitable for shortening the time required to complete an image.

[Background of the invention]

An ultrasonic diagnostic apparatus that measures the speed of movement of a moving part within a living body needs to drive an ultrasound pulse in the same direction within the living body several times in order to measure the Doppler shift frequency. However, in conventional ultrasonic diagnostic equipment in which the scanning angle and Doppler blood flow image display area are fixed, the Doppler blood flow image
When the scanning angle of the B mode image is the same, the Doppler blood flow image is B
Only a fraction of the frame rate of the mode image can be obtained, and only a Doppler blood flow image with many flickers can be obtained.

[Purpose of the invention]

An object of the present invention is to shorten the completion time of a velocity distribution image of an in-vivo moving part, increase the frame rate, and increase the frame rate in an ultrasonic diagnostic apparatus that displays a Doppler blood flow image of an in-vivo moving part. The object of the present invention is to provide a technique for improving operability by using a flow image scanning direction designation mechanism.

[Summary of the invention]

The feature of the present invention is that an ultrasonic diagnostic apparatus capable of two-dimensionally displaying the velocity distribution and velocity dispersion of a moving part in a living body is equipped with a mechanism for switching the scanning angle of ultrasound, thereby improving Doppler blood flow. This shortens the time required to complete an image, and further reduces the time required to complete an image by omitting Doppler blood flow images deep from the body surface, which are considered unnecessary for blood flow observation in areas close to the body surface. This made it possible to shorten the time.

Furthermore, in the operation for obtaining a Doppler blood flow image, it is more difficult to set the position and angle of the probe appropriately than in the case of obtaining a tomographic image. Therefore, the scanning direction of the ultrasonic pulse beam can be arbitrarily set and the image display area can be swung left and right to improve operability.

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below with reference to the drawings, together with an embodiment in which the present invention is applied to an ultrasonic diagnostic apparatus.

FIG. 1 shows a method of arbitrarily setting a scanning angle and a scanning direction when obtaining a velocity distribution and velocity dispersion using reflected waves that have undergone a frequency shift due to the ultrasonic Doppler effect in an in-vivo moving part in the present invention, and FIG. 2 is a block diagram showing a method for arbitrarily setting a scanning depth.

The output of the crystal oscillator 10 that generates a stable high frequency signal is:
The signal is supplied to the synchronization circuit 9, and various outputs of desired frequencies are obtained by the synchronization circuit 9. These output signals include an ultrasound transmission repetition signal, a reference wave signal for complex conversion, a TV synchronization signal for displaying ultrasound diagnosis results, and a clock signal for synchronizing each part of the apparatus.

The transmission edge return signal is transmitted to the transmission circuit 4 and the switching circuit 2.
The ultrasonic beam is supplied to the ultrasonic probe 1 via the ultrasonic probe 1, excites the ultrasonic probe 1, and transmits an ultrasonic beam into the subject. In addition,
Ultrasonic beam scan angle.

The scanning direction and scanning depth are determined by the Doppler blood flow image scanning angle designation circuit 20. The wave transmission control circuit 6 controls the wave transmission circuit 4 to transmit waves so that the values specified by the Doppler blood flow image scanning direction designation circuit 21 and the Doppler blood flow image scanning depth designation circuit 22 become the values.

The reflected wave from the object vibrates multiple transducers of the ultrasonic probe, becomes an electrical signal, is high-frequency amplified by the receiving amplifier 3, demodulated by the detection circuit 11, and then converted into an analog/
After being converted into a digital signal by the digital converter 12, a signal having a size corresponding to the demodulated signal is created by the encoder 13, and stored in the image memory 14 via the address generation circuit 17.
The signal is supplied to the display section as a mode display signal.

Further, the high-frequency amplified reflected wave is transmitted to a receiving phasing circuit 5.
The reflected waves obtained from the plurality of vibrators are controlled so that they all have the same phase, and are then supplied to the complex signal converter 7 and converted into a complex signal.

That is, the complex signal converter 7 uses the reference wave signal sent from the synchronization circuit 9 and a signal obtained by shifting the phase of the reference wave signal by 90 degrees using the 9o0 phase shifter 8, and converts the reference wave signal to the mixer 71.
At 72, the high-frequency amplified signal is operated on, and a complex signal can be output from each mixer. Then,
The complex signal is fed to low pass filters 73, 74 to reduce the frequency band required to obtain Doppler information. In this way, the complex transform 1 frequency band limited signal becomes A
/D converters 75 and 76 convert the signals into digital signals.

Next, the digital signal is processed by a complex delay line canceller 16, which extracts only the reflected signal component that has undergone Doppler shift due to blood flow from among the Doppler signal components having information about the in-vivo moving part, and Also, reflected signal components from parts such as the wall of the heart, where the movement speed is slow compared to the blood flow, are removed.

The average frequency of the complex signal from which the low-speed signal has been removed is calculated by the autocorrelator 18 as described above. Next, the velocity calculator 19 calculates the blood flow velocity from the deviation angle of the average frequency and calculates the blood flow velocity dispersion.

In order to display these calculation results on the display device 25, the blood flow image forming circuit 23 is used to create a signal corresponding to the calculation results.

Next, display of Doppler blood flow images and tomographic images will be explained. First, display of tomographic images will be explained.

First, in tomographic image display, as described above, the image memory 14
The data written in is read out via the address generation circuit 17, converted into a brightness modulation signal by the digital/analog converter 15, and controlled by the display control circuit 31, which is a switching circuit for Doppler blood flow images and tomographic images. 32, the display device 25 is synchronized with the synchronization signal of the TV synchronization 30.
A tomographic image is displayed above. Next, in the Doppler blood flow image display, the data of the Doppler blood flow image is transferred to the blood flow image display control circuit 2.
4 controls the write address of the 1 display memory 28 and stores it in the display memory 28. Display memory 2
The Doppler blood flow image data stored in 8 is read out via the address generation circuit 29, converted into a display signal by the digital/analog converter 27, and then controlled by the display control circuit 31. A Doppler blood flow image is displayed on the display device 25 in synchronization with the synchronization signal of the TV synchronization 3o via the image/tomogram switching circuit 26.

Note that depending on the state of the Doppler blood flow image and tomographic image switching circuits 26 and 32 controlled by the display control circuit 31, it is also possible to display the tomographic image and Doppler blood flow image in a superimposed manner.

Next, a method of arbitrarily setting the scanning angle and scanning direction, and a method of arbitrarily setting the diagnostic depth, which are the gist of the present invention, will be described.

Wave transmission control circuit 6 and Doppler blood flow image scanning angle designation circuit 20. The details of the Doppler blood flow image scanning direction designation circuit 21 and the Doppler blood flow image scanning depth designation circuit 22 will be explained using FIGS. 2 to 9.

First, FIG. 2 shows a schematic diagram of the ultrasonic diagnostic apparatus when measuring the in-vivo movement velocity. First, the velocity V in the direction of the arrow inside the blood vessel.
To measure the average velocity and velocity dispersion of blood flowing at Q,
The ultrasonic beam is sequentially scanned in a fan-shaped range. When changing the scanning angle of the Doppler blood flow image, the scanning angle at which the Doppler blood flow image is obtained is specified by the Doppler blood flow image scanning angle designation circuit 20. Next, the wave transmission side control circuit 6 changes the Doppler scan start address n and the Doppler scan end address N of the scanning range in FIG. The wave circuit 4 is controlled. An example of this is shown in Figure 3.
It is shown in Figure 4. The hatched part in FIG. 3 is a Doppler blood flow image, and the other parts are tomographic images. ! , the Dotsupura scan start address n is 20. The Doppler scan end address N is set to 30. Here, an example in which the scanning angle is changed by the method described above is shown in FIG. 4.

In this case, the Doppler scan start address n is 10 depending on the angle.
．． The Doppler scan end address N has been changed to 40.

Next, when changing the scanning direction of the Doppler blood flow image,
The scanning direction is designated by the Doppler blood flow image scanning direction designation circuit 21. Next, the wave transmission control circuit 6
The wave transmitting circuit 4 is controlled by changing the Doppler scan start address n and the Doppler scan end address N of the scanning range according to the values specified by the Doppler blood flow image scanning direction specifying circuit 21. Examples of this are shown in FIGS. 3 and 5. When the scanning direction of the Doppler blood flow image shown in FIG. 3 is changed using the above-described method, the image becomes as shown in FIG. 5. In this case, the Doppler scan start address n changes to 15 and the Doppler scan end address N changes to 25, depending on the designated direction.

Next, a method for arbitrarily setting the scanning depth will be explained. FIG. 6 shows a schematic diagram when measuring the velocity distribution of a moving part in a living body using ultrasonic waves. Here, the ultrasonic beam transmitted from the probe is reflected at various parts within the living body. These reflected ultrasound pulses are PO, PI, and P2. At this time, there is no frequency shift in the reflected wave Po from the in-vivo fixation part, but the reflected waves Pi and P2 from within the blood vessel are proportional to the movement speed of the in-vivo moving part, that is, the internal blood vessel flow velocity vo. A frequency shift occurs.

Next, FIG. 7 shows the generation state of ultrasonic pulses and the state of reflected waves during in-vivo velocity measurement. In FIG. 4, the horizontal axis represents time and the vertical axis represents signal magnitude.

A is an incident ultrasound pulse to a living body, B is a reflected ultrasound pulse from the living body, and C is a signal obtained by demodulating the signal of B with a reference wave signal of a probe. In a normal ultrasonic diagnostic apparatus, since the pulse interval T for obtaining a Doppler blood flow image is constant, the scanning depth is also constant. Therefore, in order to change the measurement depth of the Doppler signal, in the present invention, ultrasonic pulses are emitted as shown in FIG. 7(1)). That is, to obtain a tomographic image, the interval between the first and second pulses is T, but in order to obtain a Doppler blood flow image, the pulse intervals after the second pulse are shortened to Tn. The reflected pulse obtained by this is Po
, PI. That is, by changing the pulse interval TD, the scanning depth of the Doppler blood flow image can be changed. Next, this method will be explained using FIG. First, the scanning depth at which a Doppler blood flow image is to be obtained is specified using the Doppler blood flow image scanning depth designation circuit 22 shown in FIG. Next, the wave transmission control circuit 6 determines the scanning depth of the ultrasound beam according to the Doppler blood flow image scanning depth designation circuit 2.
The wave transmitting circuit 4 is controlled so that the scanning depth specified in step 2 is achieved.

These examples will be described below. FIG. 8 shows the scanning and display range of a tomographic image and a Doppler blood flow image of a conventional ultrasonic diagnostic apparatus.

Next, an example using the method of arbitrarily setting the scanning angle according to the present invention has a range shown in FIG.

Here, hatchings represent Doppler blood flow images, and the others represent tomographic images. Further, θ represents the scanning angle of the Doppler blood flow image measurement area.

Next, in the method of arbitrarily setting the scanning direction according to the present invention, as shown in FIG. 10, the direction of the Doppler blood flow image can be arbitrarily changed. In other words, the angle ψ formed between the Doppler blood flow image and the tomographic image can be arbitrarily changed.

Next, in the method of arbitrarily setting the scanning depth according to the present invention, as shown in FIG. 11, the depth of the Doppler blood flow image can be arbitrarily set. Here, t is the depth of the Doppler blood flow image.

In addition, in the present invention, the case where a sector type probe is used as an ultrasonic probe has been explained, but other probes include a linear scanning type probe, a convex type probe, etc. Even when a probe is used, the effects described in the present invention can be obtained.

In addition, in the present invention, an ordinary ultrasonic transmission/reception method was used as the ultrasonic reception method, but in order to obtain a higher frame rate, By using a method of receiving ultrasonic waves in multiple directions in addition to transmitting ultrasonic waves in one direction as shown in Application No. 84344, it is possible to further shorten the image completion time, making it suitable for diagnosis. images can be provided.

The effects of this embodiment are shown below.

(1) By arbitrarily setting the scanning angle and scanning depth of the ultrasonic pulse beam, the completion and retention time of the Doppler blood flow image can be shortened, and flickering of the Doppler blood flow image can be reduced.

(2) By appropriately setting the scanning angle and scanning depth, it is possible to omit the scanning 9 display of Doppler blood flow images in parts that are considered unnecessary for one diagnosis, and to obtain an easy-to-read image.

(3) By arbitrarily setting the scanning direction, a Doppler blood flow image of the area to be examined can be easily obtained, and operability can be improved.

(4) By combining methods of arbitrarily setting the scanning angle, scanning direction, and scanning depth, the above (1) can be achieved.

The effect of combining (2) and (3) can be obtained, and images suitable for diagnosis can be provided.

〔Effect of the invention〕

According to the present invention, in an ultrasound diagnostic apparatus capable of two-dimensionally displaying the velocity distribution and velocity dispersion of a moving part in a living body using the ultrasonic pulse Doppler method, a Doppler blood flow image scanning angle switching mechanism, a Doppler blood flow By providing the image scanning direction specifying mechanism and the Doppler blood flow image scanning depth specifying mechanism, the following effects can be obtained.

(1) The frame rate of Doppler blood flow images can be increased by the scanning angle switching mechanism and the mechanism that can arbitrarily set the scanning depth, and images suitable for diagnosis can be obtained.

(2) A mechanism that allows the Doppler blood flow image display area to be swung from side to side at an arbitrary inclination improves operability and facilitates diagnosis.

(3) By arbitrarily setting the scanning angle and scanning depth of the ultrasonic pulse beam, the time required to complete a Doppler blood flow image can be shortened, and flickering in the Doppler blood flow image can be reduced.

(4) By appropriately setting the scanning angle and scanning depth, an easily viewable image can be obtained by omitting the display of the Doppler blood flow image in scan 2 in parts that are considered unnecessary for diagnosis.

(5) By arbitrarily setting the scanning direction, a Doppler blood flow image of the area to be examined can be easily obtained, and operability can be improved.

(6) (1), (2), (3), (4),
(5) makes it possible to provide images suitable for diagnosis.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the general configuration of the ultrasonic diagnostic apparatus, which is only for explaining an ultrasonic diagnostic apparatus according to an embodiment of the present invention. FIG. 2 shows a principle diagram showing an outline of the in-vivo velocity measurement of the ultrasonic diagnostic apparatus. Third
5 to 5 are diagrams showing changes in the Doppler blood flow image area according to the present invention. Figures 6 and 7 show the generation state 9 of the ultrasonic pulse regarding Doppler blood flow image measurement.
- It is a diagram showing the state of the demodulated signal. FIG. 8 shows the ultrasound scanning range in a conventional ultrasound diagnostic device, and FIGS. 9 to 11 show the in-vivo velocity distribution measurement range and in-vivo blood flow image display in the ultrasound diagnostic device using the present invention. It is a figure showing a range. 1... Probe, 2. 26. 32... switching circuit,
3... Wave receiving amplification circuit, 4... Wave transmitting circuit, 5... Wave receiving phasing circuit, 6... Wave transmitting control circuit, 7... Complex signal converter, 71°72...・Mixer, 73.74...Low-pass filter, 75°76...Analog/digital converter, 8...90° phase shifter, 9...Synchronous circuit,
10...Crystal oscillator, 11...Detection circuit, 12...
- Analog/digital converter, 13... Encoder, 14... Image mail E-IJ. 15.27...Digital/analog converter, 1
6... Complex delay 2-ink canceller, 17. :=2
9...Address generation circuit, 18...Autocorrelator. 19... Velocity calculation circuit, 20... Drifting blood flow image scanning angle designation circuit, 21... Doppler blood flow image scanning direction designation circuit, 22... Doppler blood flow image scanning depth designation circuit,
23... Blood flow image configuration circuit, 24... Blood flow image display control circuit, 25... Display device, 28... Display memory,
30...TV synchronization circuit, 31...Display control circuit. 6th prison carving anti-Hee fist wa figure 80th 9th 1N Kaisho 62-22636 (8) 1st to 121 Satoru 11 figure

Claims (1)

[Claims] 1. By transmitting an ultrasonic pulse beam into a living body in a repeated cycle and receiving the reflected waves, B mode or M
A device that displays an ultrasound image of a mode, and a device that has a frequency that is an integral multiple of the transmission repetition frequency and has a complex relationship with each other, in order to detect the frequency shift of the reflected wave that has undergone Doppler shift due to the moving part in the living body. a complex signal converter that converts the received high-frequency signal into a complex signal by mixing a set of complex reference signals and a received high-frequency signal obtained by receiving and amplifying reflected waves; and removing signals of low-speed moving parts in the living body from the complex signal. an autocorrelator that calculates the autocorrelation of the complex signal by setting a delay time of the complex signal, and a velocity calculator that calculates the argument of the autocorrelation, An ultrasonic diagnostic apparatus that measures a motion velocity distribution and displays an image of the motion velocity distribution of the in-vivo moving part, characterized in that the ultrasound diagnostic apparatus is provided with a Doppler blood flow image scanning angle switching mechanism. 2. A device that displays a B-mode or M-mode ultrasound image by transmitting an ultrasonic pulse beam into a living body at a repetitive frequency and receiving the reflected wave, and a device that displays Doppler shift due to the moving part in the living body. In order to detect the frequency shift of the received reflected wave, a set of complex reference signals having a frequency that is an integral multiple of the transmitted repetition frequency and having a complex relationship with each other is mixed with a received high-frequency signal obtained by receiving and amplifying the reflected wave. a complex signal converter that converts a received high frequency signal into a complex signal; a complex delay line canceller that removes a signal from a low-speed moving part in the body from the complex signal; An ultrasonic diagnostic apparatus that measures a motion velocity distribution of a moving part in a living body and displays a Doppler blood flow image, including an autocorrelator that computes an autocorrelation and a velocity calculator that computes a declination angle of the autocorrelation. An ultrasonic diagnostic apparatus characterized by being provided with a Doppler blood flow image scanning direction designation mechanism. 3. A device that displays a B-mode or M-mode ultrasound image by transmitting an ultrasonic pulse beam into a living body at a repetitive frequency and receiving the reflected wave, and a device that displays Doppler shift due to the moving part in the living body. In order to detect the frequency shift of the received reflected wave, a set of complex reference signals having a frequency that is an integral multiple of the transmitted repetition frequency and having a complex relationship with each other is mixed with a received high-frequency signal obtained by receiving and amplifying the reflected wave. a complex signal converter that converts a received high frequency signal into a complex signal; a complex delay line canceller that removes a signal from a low-speed moving part in the body from the complex signal; An ultrasonic diagnostic apparatus that measures a motion velocity distribution of a moving part in a living body and displays a Doppler blood flow image, including an autocorrelator that computes an autocorrelation and a velocity calculator that computes a declination angle of the autocorrelation. An ultrasonic diagnostic apparatus characterized by being provided with a Doppler blood flow image scanning depth designation mechanism.