JPS6099237A - Ultrasonic vibrator 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] [Technical Field of the Invention] This invention relates to ultrasonic waves that display a two-dimensional distribution of flow within a subject by superimposing it on a tomographic image of the subject's tissue [Prior Art] Conventionally, intracardiac An example of this type of device intended for measuring the blood flow distribution of blood flow is shown in FIG. In the figure, ■ is an array-type probe that transmits and receives ultrasound by contacting the living body, and 2 is a sector-scanning tomography device that uses probe l to scan the ultrasound beam in a fan shape and capture the tissue inside the living body as an image. (ultrasonic tomographic imaging device), the tomographic device 2 includes:
a transmitting circuit 21 that transmits an ultrasonic beam in a predetermined direction;
A receiving circuit 22 that receives ultrasonic echoes returning from the same direction, a signal processing circuit 23 that converts the received signal into a signal that can be displayed on a CRT, and a display 24 consisting of a CRT that displays the output thereof, and controls these. It is composed of a control circuit 25 that performs the following steps. Further, 31, 32, 33.34 are gates for extracting signals of each part according to the distance from the object surface from the output signal of the receiving circuit 22 of the sector scanning tomography apparatus 2, and 41.42, 43.44 are each gate. 31,32゜33
．． Frequency analyzers 51, 52, and 53 perform AD conversion on the signal extracted at 34 and Fourier transform using an FFT processor (not shown). 6 is a memory for storing the calculation results, and 7 is a display for displaying the contents of the memory 6.

Next, the operation will be explained. First, the sector scanning tomography device 2 controls the transmission circuit 21 according to instructions from the control circuit 25, and controls the probe 1 which has a large number of piezoelectric transducers arranged in parallel.
The ultrasonic pulse is transmitted in a predetermined direction. At this time, the receiving circuit 22 is also controlled in a similar manner, and detects ultrasonic waves arriving in the opposite direction from the direction in which the ultrasonic pulses were transmitted. These operations are known as phased arrays.

Ultrasonic pulses transmitted in a predetermined direction (in FIG. 1, the direction of arrow A penetrating the heart 8) are reflected by tissues such as the wall of the heart 8 and red blood cells on the propagation path, and are detected by the probe 1. be done. The detected signal is given sharp directivity and amplified in the receiving circuit 22 as described above.
The signal is input to the signal processing circuit 23. Then, the signal processing circuit 23 removes echoes from red blood cells from the output of the receiving circuit 22, leaving only echoes from tissues such as walls, and further removes echoes from the red blood cells from the output of the receiving circuit 22.
Processing such as amplitude compression is performed for display on T. Display 2
4, the output of the signal processing circuit 23 is brightly modulated in the direction designated by the control circuit 25 to perform display.

Note that the above-mentioned removal of red blood cell echoes can be achieved by using an amplifier having a dead zone near 0, since the amplitude of red blood cell echoes is extremely small compared to wall echoes.

The output of the receiving circuit 22 is sent to the signal processing circuit 23 as described above.
It is also input to gates 31, 32, 33, and 34, and echo signals for each section on the ultrasonic propagation path are extracted. This situation is shown in Figure 2.
When ultrasonic waves are transmitted in one direction A of the heart 8 as shown in al, echoes return from each tissue and are received as shown in fb) of the same figure. As shown on the arrow A in the same figure (al), the left ventricle is divided into sections Kl, 2., 3. and 4, and correspondingly, the left ventricle is divided into sections Kl, 2., 3. and 4. When control signals are generated as shown in the figure fcl, (d), (e), and (fl), each gate corresponds to the control signals shown in the figure (g).
, fhl, (1), 2. for each section Kl, like 01. 3. Only the echo signals generated in 4 and 4 are extracted.

These signals are processed by frequency analyzers 41°42.4, respectively.
3.44 and after each AD conversion, a power spectrum is determined by an FFT processor (not shown). At this time, the center frequency fv of the power spectrum in each section is determined by the following equation due to the Doppler effect.

where f is the frequency of the transmitted ultrasound, C is the speed of sound in the living body,
(2) is the ultrasonic wave transmission/reception direction component of the blood flow velocity in each section.

Therefore, the blood flow rate ■ is determined. This calculation is carried out by calculating units 51, 52, .
53. '54 and the results are recorded in memory 6. When the above operation is completed in one direction A, the control circuit 25 shifts the direction of ultrasonic transmission and reception, and thereafter performs the same calculation as above, and writes the result to the memory 6. In this way, when the range of interest is scanned by sequentially shifting the ultrasound transmission/reception direction, the contents of the memory 6 will show the blood flow distribution in those ranges, and this will be displayed on the display 7.

In the above explanation, one ultrasound propagation path is divided into four sections for simplicity, but if you actually want to know detailed blood flow distribution, it is necessary to divide the ultrasound propagation path into many sections. ,
Accordingly, it is necessary to provide a large number of gates, frequency analyzers, and arithmetic units.

In addition, in the above explanation, we have shown the case where the spectrum is calculated from the echo signal obtained by one transmission/reception, but in reality, the echo spectrum is wide, so in order to clarify the center frequency, it is necessary to calculate the spectrum from the echo signal obtained by one transmission/reception. , a method is used in which ultrasonic waves are continuously transmitted and received, and the spectrum is determined for a large number of echoes with the same characteristics. Therefore, it takes several tens of m5 ec to measure the blood flow distribution in one direction, and it takes nearly 1 Qsec to scan the entire target area, which is not real-time.

Conventional ultrasound diagnostic equipment is configured as described above, so it can only measure the one-dimensional component of blood flow velocity, that is, the ultrasound transmission/reception direction component, and requires a large amount of expensive honeydewware such as frequency analyzers. However, there were drawbacks such as the inability to measure blood flow distribution in real time.

[Summary of the invention]

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and it captures the echoes of particles contained in the flow of liquid inside the subject as an image, and by the temporal change of the echoes, the points in the image can be determined. The object of the present invention is to provide an ultrasonic diagnostic device that can measure two-dimensional blood flow distribution in real time by detecting the amount of movement and its direction by a correlation method.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. Third
In the figure, 1 is a probe, 2 is a sector scanning tomography device, and 101 is a digital scan converter (hereinafter referred to as DSC) that converts the A-mode signal output from the sector scanning tomography device 2 into a rask scan format signal. ), the DSC+01 has a function of extracting echo image information of particles contained in the flow of fluid inside the subject from the output image of the A-mode signal of the sector scanning and cutting device 1-2, prior to signal conversion. It is something that we have.

102 is a memory that temporarily stores the output signal of the DSCIOI; 103 is a correlation calculation circuit that calculates the local correlation between the output of the DSCIOI and the contents of the memory 102, that is, the correlation between partial images of both outputs; and 104 is a correlation calculation circuit that calculates the correlation between the partial images of both outputs; This is a vector display memory that stores flow velocity vectors. Further, the sector scanning type tomographic apparatus 2 has the same structure as the conventional one shown in FIG. However, here, the direct 11:i of the display 24
In this figure, an SC 26 is inserted and a TV monitor is used as the display 24.

Next, the operation will be explained.

The operation of the sector scanning tomography device 2 is the same as the conventional one,
Ultrasonic pulses are transmitted in a predetermined direction from the probe 1, and echoes generated in each tissue along the propagation path are received again by the probe 1. This direction is sequentially shifted for each transmission/reception to scan the target yoke. The signal obtained by this is sent to the DSCZ6 through the signal processing circuit 23, and the signal is sent to the DSCZ6.
6, AD conversion is performed, polar coordinates are converted to XY coordinates, and these XY coordinate values are further written into the memory in the DSC 26. The contents of this memory are read out in accordance with the 1'' synchronization signal and displayed on the display 24. That is, the display 24 displays an lti III image of tissues such as walls, excluding echoes from red blood cells.

On the other hand, the output signal of the receiving circuit 22 is also sent to the DSCI OL, and similarly to the DSC 26, after AD conversion and coordinate conversion, it is written into the memory in the DSCI OL, and is read out in the form of a TV signal. The output signal of DSClol is written to the memory 102 at regular time intervals and is sent to one input of the correlation calculation circuit 103. In addition to this DSCIOI output, the memory 1 is also sent to the correlation calculation circuit 103.
02 output is given. The content of the signal input to DSCI O1 is a superimposed tomographic image of tissues such as walls and echo images of red blood cells, as shown in Figure 4.
Since CIOI is designed to automatically obtain echo images of red blood cells, the tomographic image of the tissue is saturated and a considerable amount of information is lost. Now, consider only the echo image portion of red blood cells, for example, the portion of image B in FIG. 4. Figure 5 is an enlarged version of this.

This is written to the memory 102 at a certain timing,
After a certain period of time has passed, the output of DSCIOI changes as shown in FIG. This is because the red blood cells in this area moved to the right, so the image is slightly shifted to the right compared to the one in Figure 5.

Now, as shown in FIG. 5, the coordinates (X
, Y) with a predetermined size, such as F1100, on the image of DSC]01, a predetermined size larger than the partial image F centered on the coordinates (X, Y). Let H be the second partial image of . Corresponds to the echo height in each image F, H.

Let the density of each pixel be r (x, y), h (x, y)
The cross-correlation between image F and image G, which has the same size as F in image H, is calculated. That is, at the center of the same large image G,
If the deviation from the center of the second partial image @H is (u, v), the density of the pixel of the same large image G is g (x + u, y + v
), and in this case, the cross-correlation Cfg is expressed as: Cfg= If (x, y) ・g (x+u, y
+v') dxdy. And this cross-correlation C
fg is iI! ! I is considered for all possible (u, v) in the image H. When the above calculation is completed for one partial image F, (X, y) is moved one after another, and the same calculation is performed over the entire region B. Along with this,
Ig2(x+u, y+v) dxdy is calculated, and the cross-correlation Cfg is normalized by this value.

The above results are sent to the vector display memory 104, whereby the parameters θ and ρ are determined as follows.

θ-tan-' (v/u) β-n This is the angle θ direction from the center (X, y) in image H.
There is an image that is most similar to image F, centering on a point with distance l, that is, the echo source of (x, y) is
That is, it indicates that the DSCIOI has moved by a distance l in the θ direction during the period in which the contents of the DSCIOI are periodically written to the memory 102, and the vector information (θ, I2) indicates the flow of red blood cells, that is, the blood flow. . The vector information (θ, β) is written to the display memory 104 in the same format as the memory in the DSC 26, while being read out in the format of a TV signal and displayed on the display 24.

The format of writing to the vector display memory 104 is such that when vector information is displayed on the display 24, it becomes an arrow with length l and direction θ, so when you look at the display results, you can see the flow of each point. You can immediately and intuitively know the direction and speed of the object.

In this way, Honjiri i! In example i, the red 1
Since the amount of movement and the direction of movement of the sphere 111 are detected by a correlation method, two-dimensional blood flow distribution can be measured in real time despite the small-scale circuit configuration. Since the output and the output are input to the same display 24, there is an effect that the blood flow inside the subject and the tomographic image of the tissue can be displayed in a superimposed manner on one screen.

In the above embodiment, the vector information B, θ) is displayed as an arrow whose length is l and whose direction is an inclination θ. The direction and size may be expressed by the brightness of the primitive line. In this case, information about the positive and negative directions is lost, but since there are no arrows and their lengths are uniform, an easy-to-see image can be obtained.

Furthermore, the sign or negative of the direction that is lost at this time can be displayed in the color of the line, for example, in red for the positive direction and blue for the negative direction. Alternatively, the vector information may be displayed with the direction indicated by the slope of a line of a certain length and the magnitude indicated by color.

Furthermore, the vector information may be displayed with its direction in color and its size in brightness. In this case, since the vector corresponding to each point can be displayed as a point, a cleaner image can be obtained than when it is displayed as an arrow or a straight line.

Furthermore, in the above embodiment, an example was shown in which a sector scanning type ultrasonic tomographic imaging device using a phased array was used, but it goes without saying that a mechanical sector scanning type or a linear scanning type may also be used. do not have.

Furthermore, in the above embodiment, a case was shown in which ultrasonic echoes of red blood cells were imaged, but as in the contrast echo method carried out in the field of medical ultrasonic diagnosis, there is a substance in the subject that acts as an echo source. The substance may be injected from the outside and the echoes of this substance may be imaged to display the flow of fluid within the subject.

Furthermore, although the above-mentioned embodiment shows the case of measuring the blood flow in the heart, the present invention can also be applied to measuring the flow velocity distribution of the fluid 202 flowing through the pipe 201, as shown in FIG. In FIG. 8, 203 is an echo source, which is injected into the pipe 201 from the injection pipe 204 shown on the left side. Further, 2 is a linear scanning type ultrasonic tomographic imaging device, and 2 is an array type probe for linear scanning.

In this case, the flow velocity distribution in the pipe directly below the probe l is measured and displayed on the display device 24. According to this, since the distribution of flow velocity vectors is measured instead of the average flow velocity, it is also possible to construct a highly accurate flow meter.

〔Effect of the invention〕

As described above, according to the present invention, an image of particles dispersed in a fluid flowing through the body tissue of a subject is obtained, and the flow velocity distribution is determined from the temporal change using the correlation method. This has the effect of being able to measure the flow velocity of the liquid within the specimen in real time as a two-dimensional vector.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a conventional ultrasonic diagnostic device, Fig. 2 is a received waveform diagram for explaining the operation of the device shown in Fig. 1, and Fig. 3 is a block diagram of a conventional ultrasonic diagnostic device.
The figure is a block diagram of an ultrasonic diagnostic apparatus according to an embodiment of the present invention, FIG. 4 is a diagram showing an example of the image written to the memory in FIG. 3, and FIG. 5 is an enlarged view of a portion of the image in FIG. 4. ,
6 is a diagram corresponding to the image in FIG. 5 after a predetermined time has elapsed, FIG. 7 is an enlarged view of a portion of the images in FIGS. 5 and 6, and FIG. 8 is another embodiment of the present invention. FIG. DESCRIPTION OF SYMBOLS 1... Probe, 2... Sector scanning tomography device (ultrasound tomography device), 101... DSC (particle echo image extraction means), 102... Memory, 103... Correlation calculation circuit, 104...Vector display memory, 24...
・Display device. Note that the same reference numerals in the figures indicate the same or equivalent parts. Agent Masuo Oiwa Figure 2 (j)t Figure 4 Figure 6 Figure 7 Procedural amendment (voluntary) 20 Name of invention Ultrasonic diagnostic device 3, Relationship to the person making the amendment Patent applicant address Tokyo 2-2-3 Marunouchi, Chiyoda-ku, Miyako
(601) Mitsubishi Electric Corporation Representative Hitoshi Katayama 4, Agent Address 2-2-3-5 Marunouchi, Chiyoda-ku, Tokyo, Detailed Description of the Invention Column 6 of the Specification Subject to Amendment, Lii Masano Contents (1) “To obtain...” on page 12, lines 5-6 of the specification
...is lost. '' should be corrected to ``Because the sensitivity is increased to obtain a higher echo amplitude, tomographic images of tissues with large echo amplitudes are saturated, and echo images of red blood cells appear prominently.''that's all

Claims (7)

[Claims] (1) A scanning probe that contacts the surface of a subject and transmits ultrasonic pulses into the body and receives echoes from the body tissues of the subject; an ultrasonic tomographic IFj imaging device that obtains a tomographic image of body tissues from received signals; and a particle echo image that extracts echo images of particles contained in the flow of fluid within the subject from among the output images of this ultrasonic tomographic imaging device. an extraction means, a memory for temporarily storing the particle echo image, a correlation calculation circuit for correlating the image stored in the memory with the output image of the particle echo image extraction means, and a calculation result of the correlation calculation circuit. A vector display memory stores slip information expressed in a vector format, and the contents of this vector display memory and the moon curve image of the ultrasonic tomographic imaging device are combined. What is claimed is: 1. An ultrasonic diagnostic apparatus comprising: a display device for displaying images. (2) The correlation calculation circuit divides either the output image of the ultrasonic tomographic imaging device or the output image of the memory into a first partial image of a predetermined size, and The output image is a second partial image centered on the image corresponding to each of the first partial images and including the image and its vicinity, and the first partial image and the second partial image are It calculates the cross-correlation between the first partial image and all of the images of the same size, and the vector display memory calculates the cross-correlation between the first partial image and all the images of the same size, and the vector display memory calculates the cross-correlation between the first partial image and all the images of the same size, and the vector display memory calculates the cross-correlation between the first partial image and all of the images of the same size. 2. The ultrasonic diagnostic apparatus according to claim 1, wherein the distance and direction between the center and the center of the second partial image are stored as a flow velocity vector. (3) The display device is characterized in that the vector information is displayed with the direction indicated by an arrow and the magnitude thereof indicated by the length of the arrow. Sonic diagnostic equipment. (4) The display device is characterized in that the vector information is displayed in the form of a line of a certain length as its direction and as the brightness of an original line as its size. The ultrasonic diagnostic device described. (5) The display device displays the vector information using the color of a line of a certain length as its direction and the brightness of an original line as its size. Ultrasound diagnostic equipment. (6) The display device displays the vector information in the direction of a line of a certain length and its size in the color of the original line. Ultrasound diagnostic equipment. (7) The display device is characterized in that the vector information is displayed with its direction as a direction of a line of a certain length, its direction as the color of the original line, and its size as the brightness of the original line. An ultrasonic diagnostic apparatus according to claim 1.