JPS61220637A - Doppler blood flow image display method for 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] [Technical Field] The present invention relates to an ultrasonic diagnostic apparatus, and in particular, performs calculations to measure the average velocity, velocity dispersion, and reflection intensity of a moving part in a living body, and uses the calculation results based on the calculation results. The present invention relates to a technique that is effective when applied to a technique for correcting one display content when displaying an in-vivo motion partial velocity distribution.

[Background technology]

Some ultrasonic diagnostic devices that use the conventional ultrasound Doppler effect to display velocity distribution images of in-vivo moving parts display the displayed Doppler blood flow images in color, but this is different from the actual It does not show the blood flow velocity in the blood flow direction in color. That is, as shown in FIG. 13, the velocity of the blood flow at the measurement point where the blood flow and the ultrasonic pulse beams bI to b9 intersect is a velocity that depends on the incident angles θ1 to θ9 of the ultrasonic pulse beams to the blood flow. Therefore, the difference in beam direction affects the hue of the displayed Doppler blood flow image. For this reason, there is a problem that there is a risk of misdiagnosis.

[Purpose of the invention]

An object of the present invention is to obtain a blood flow velocity distribution image in which measured blood flow velocity information is corrected to a value in an arbitrarily set vector direction in an ultrasonic device that displays the velocity distribution of a moving part in a living body. Our goal is to provide the technology that makes it possible.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Summary of the invention]

A brief overview of typical inventions disclosed in this application is as follows.

That is, by transmitting an ultrasonic pulse beam into the living body at a constant repetition period and receiving the reflected waves, B
A display means for displaying a Doppler blood flow image in a living body by detecting a frequency shift of a reflected wave subjected to a Doppler shift due to a moving part in the living body; means for freezing the screen display;
A means for setting an arbitrary vector set on this frozen Dotsupura blood flow image screen, a means for correcting velocity distribution information measured at the base point of each vector set by this means to a value in the vector direction, and a means for correcting this correction. By providing a means for converting the measured value into color display information and a means for displaying a Doppler blood flow image composed of this color information, the measured blood flow velocity information can be corrected to a value in the vector direction. This allows a blood flow velocity distribution image to be obtained.

[Structure of the invention]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below with reference to the drawings and an embodiment in which the present invention is applied to an ultrasonic diagnostic apparatus that obtains information on moving parts within a living body using the ultrasonic pulse Doppler method. In addition, in an attempt to explain the embodiments, parts having the same functions are given the same reference numerals, and repeated explanation thereof will be omitted.

First, the principle of the Doppler blood flow image display method for an ultrasound diagnostic apparatus of this embodiment will be explained using FIGS. 1 to 6.

The principle of the Doppler blood flow image display method for ultrasonic diagnostic equipment is that in order to obtain a blood flow velocity distribution image that follows the actual flow direction of blood flow as shown in Figures 2 and 3, to do,
The velocity distribution information measured at the base point of each of the set vectors is set as the angle of incidence of the ultrasonic pulse beam on the blood flow at the measurement point where the blood flow and the ultrasonic pulse beam intersect. The dependent speed data is used to correct the value in the vector direction.

For this reason, as shown in Figure 4, a vector is set at an arbitrary point in the Doppler blood flow image during freezing to give the direction of blood flow using the arrows used in conventional one-dimensional Doppler devices. Furthermore, by increasing the number of vectors that can be set, a blood flow distribution within a blood vessel as shown in FIG. 1 can be obtained in any direction of blood flow.

In addition, in the above case, the vector component of the blood flow velocity at the base point of the vector was corrected, but in addition, in the vicinity of this vector, for example, as shown in FIG. By performing corrections on the measurement points on the intersection with the USL and several measurement points before and after each measurement point, it is possible to make corrections that take into account the width of the blood vessel.

Furthermore, in the above method, the correction direction is represented by a vector array as shown in FIG. 1, but as shown in FIG. By using vectors connecting each, it is also possible to indicate the direction of correction using a curve.

〔Example〕

FIG. 7 to FIG.
The figure is a block diagram showing a schematic configuration of an apparatus for implementing the Doppler blood flow image display method, and FIGS. 8 to 10 are explanatory diagrams showing display images for explaining this Doppler blood flow image display method. be.

In FIG. 7, 1 is an ultrasonic probe, and 200 is a two-dimensional Doppler device, which includes a processing section 200A and a display section 200B. Reference numeral 20 denotes an image storage device, which is used to store speed data for four minutes of one frame on the screen. 6
0 is a display correction arithmetic processing unit, which is used to correct equations. 300 is a control device for controlling each of the above devices.

In the Doppler blood flow image display method for an ultrasound diagnostic apparatus of this embodiment, in FIG. 7, after freezing the display of the Doppler blood flow image screen, based on velocity distribution information stored in the image storage device 20, This is a method of correcting velocity distribution information at points of intersection with these vectors to values in the vector direction by providing arbitrary vector sets to a frozen Doppler blood flow image.

That is, as shown in FIG. 8, the blood flow velocity on any ultrasonic pulse beam line USL is generally determined by the Doppler shift frequency fd when the blood flow velocity is V and the incident angle is θ. Considering that the sound velocity C of the ultrasonic wave at is sufficiently larger than the blood flow velocity V, it can be approximately expressed by the following equation (1).

However, in the case of blood flow, the velocity information obtained by the two-dimensional Doppler apparatus 200 is obtained by ignoring the angle of incidence of the ultrasonic pulse beam line USL with respect to the blood flow, so Equation (2)
No correction by cos O shown in . That is, as shown in Fig. 4, blood flow is assumed to be flowing in the direction of the ultrasonic pulse beam line USL, velocity is measured, and the actual blood flow velocity is determined along the ultrasonic pulse beam line USL.
The velocity V of only the direction component is obtained.

Therefore, as shown in FIGS. 8 and 9, the actual velocity is determined by setting a vector that gives the actual blood flow direction. Therefore, as shown in Fig. 10, the vector giving the actual blood flow direction and the ultrasonic pulse beam line U
Obtain angles α and β from SL. Note that the angle α is unique to the ultrasonic diagnostic apparatus and is determined for each address of the ultrasonic pulse beam line USL, so it can be determined if the address of the ultrasonic pulse beam line USL is known. Further, the angle β can be determined by a blood flow pattern position specifying device, which will be described later, from the settings of, for example, a track board, joystick, light ben, etc.

Further, the angles α and β are angles with respect to the center of the Doppler blood flow image as a reference line for correction.

In this way, the value of the angle of incidence of the ultrasonic pulse beam line USL into the bloodstream can be determined from the equation 180 = (α+β), and can be corrected using equations (1) and (2) above.

Next, implementation of the Doppler blood flow image display method of this embodiment will be described.

FIG. 11 is a block diagram showing the detailed configuration of an ultrasonic diagnostic apparatus that implements the Doppler blood flow image display method of this embodiment, and FIG. 12 is a Doppler blood flow image display method of this embodiment shown in FIG. FIG. 2 is a block diagram showing the configuration of a part that implements the main part of the system.

In FIG. 11, the output of a crystal oscillator 10 that generates a stable high-frequency signal is supplied to a synchronous circuit 11, and the synchronous circuit 11 provides various outputs of desired frequencies. These output signals include an ultrasound transmission repetition signal, a TV synchronization signal for complex conversion, and a clock signal for synchronizing each part of the apparatus.

The transmitted wave repeating signal is supplied to the ultrasound probe 1 via the wave transmission circuit 3 and the switching circuit 2, excites the ultrasound probe 1, and transmits an ultrasound pulse beam into the subject. It is now possible to do so.

The reflected wave from the object is high-frequency amplified by the receiving amplifier 4A, demodulated by the detection circuit 50, and then converted into an analog signal.
It is converted into a digital signal by a digital converter (hereinafter referred to as A/D converter) 14', and then sent to the encoder 1.
9' to create a signal with a size corresponding to the demodulated signal,
The gain level difference is corrected by the two-channel level difference correction circuit 55, stored in the image memory 20', and supplied to the display section as a normal B mode or M mode display signal.

Further, the high-frequency amplified reflected wave is demodulated by the mixer 6 using a reference wave signal for complex conversion. In addition, in order to indicate the direction of blood flow, the reference wave is
'The phase-shifted and amplified received signal is sent to the mixer 7.
It is demodulated by

Of the Doppler signal components that have in-vivo movement information, only the reflected signal components that have undergone Doppler shift due to blood flow are extracted, and the movement speed is slow compared to the blood flow in parts that are fixed in the body and the heart wall. A complex signal canceller 15 is provided to remove reflected signal components from the portion. This complex signal canceller 15 uses a two-channel one.

The complex signal canceller 15 in the complex signal subjected to Doppler shift functions as a motion velocity calculation circuit that calculates the motion velocity of the in-vivo moving part using the extracted blood flow signal components. A reflection intensity calculator 16 that calculates the intensity, an average velocity calculator 17 that calculates the average Doppler shift frequency, that is, the relative velocity of the blood flow depending on the ultrasonic pulse beam and the blood flow direction, and the relative velocity dispersion thereof. A speed dispersion calculator 18 is used for calculation. This calculation method and the method of constructing an in-vivo Doppler blood flow image from the calculation results are described in detail in the specification and drawings of Japanese Patent Application No. 1119/1983. In order to display the above calculation results on a display device, an encoder 19 is used to create a signal having a magnitude corresponding to the calculation results.

In order to write the Doppler blood flow image signal output by the encoder 19 into the image storage device 20, an address is generated by the Doppler blood flow image writing address generation circuit 75, and the address switching circuit 74 is switched to the Doppler blood flow image writing side. , the image storage device 20 is accessed using the address, and the Doppler blood flow image data is sequentially stored in the image storage device 2.
o.

Here, the image storage device 20 is a read/write memory (
RAM: Randon+ Access Mem
ory), and the reflection intensity image memory 20a
, average speed image memory 20b, speed variance image memory 20
It consists of c.

The display correction arithmetic processing device 60 also includes an arithmetic processing unit (hereinafter referred to as CPU) 60a, a RAM 60c,
ROM (Read Only Memory) 60
In order to obtain a velocity distribution image in the actual flow direction of blood flow, the vector set giving the direction of blood flow is read, and the reflection intensity image memory 20a, the average velocity image memory 20b, and the velocity dispersion image memory This is for correcting data from the velocity distribution of each measurement point stored in 20C, and correcting the velocity of each point in the vector direction. The ROM 60b stores software for correction.

The display correction calculation process is first performed by the display correction calculation processing device 60.
Thus, the angle α of the ultrasonic pulse beam line USL with respect to the correction reference line is determined. Next, the velocity information corresponding to the base point of each vector is read from the average velocity image memory 20b, and the angle of incidence 0 is determined from the angle α and β obtained above, and the velocity of equation (1) and equation (2) is calculated. By correcting the data and storing it again in the average speed image memory 20b, the value corrected to the speed in the vector direction is displayed.

Next, a method for displaying a B-mode or M-mode Doppler blood flow image and a normal US image on the display device 24 will be described.

The Doppler blood flow image signal stored in the one-image storage device 20 by the Doppler blood flow image signal read address generation circuit 7B and the Doppler blood flow image signal write address generation circuit 74 is converted into a Doppler blood flow image j15- configuration circuit 93. The data is transferred to the display memory 21 via the.

Furthermore, the blood flow pattern image signal stored in the image memory circuit is transferred to the display memory 2 by the address generation circuit 21' and the blood flow pattern writing address generation circuit 96.
Transferred to 1.

The data stored in the display memory 21 is read out via a display readout address generation circuit 97 and an address switching circuit 98, and converted into a brightness modulation signal by a digital-to-analog converter (hereinafter referred to as D/A) 22. and in synchronization with the TV synchronization signal from the TV synchronization circuit 100,
Through the switching circuit 23, the Doppler blood flow image is displayed on the display device 24.
will be displayed.

On the other hand, the ultrasonic tomographic image data stored in the image memory 20' is read out by the address generation circuit 21'.
The D/A converter 22' converts the signal into an analog luminance modulation signal, and the ultrasonic tomographic image is displayed on the display device 24 via the switching circuit 52.

116= The blood flow pattern position specifying device 76 divides the display area into two parts using an ultrasound beam line or the like in the Doppler blood flow image.
It is a device that divides or sets an arbitrary number of BETTR sets, and uses, for example, a joystick, trackball, light pen, etc.

In this embodiment, a color encoder is used as the encoder 19, and red (R), green (
G) and blue (B), and the speed is displayed in color using a color plan tube as a cathode ray tube of the display device 24. Regarding this display means, Japanese Patent Application No. 59-2361
It is described in detail in the specification and drawings of No. 99.

As can be seen from the above description, according to this embodiment, the following first-order effects can be obtained.

(1) Set a set of vectors that give the blood flow direction, and based on this set, the velocity distribution information stored in the image storage device 20 is used to calculate the ultrasonic pulse beam at the measurement point where the blood flow and the ultrasonic pulse beam intersect. By correcting the velocity data depending on the incident angle of the blood flow, it is possible to obtain an image of the velocity distribution in the actual blood flow direction.

(2) When correction is performed according to (1) above, in contrast to conventional display methods, blood flow at a constant velocity becomes an image with differences in color shading and color system depending on the ultrasonic pulse beam angle. , the same density and the same color system, it is possible to provide organized diagnostic information such as an actual in-vivo velocity distribution image.

(3) According to (2) above, the possibility of misdiagnosis can be reduced.

Although the present invention has been specifically explained above using examples, the present invention is not limited to the above-mentioned examples, and it goes without saying that various modifications can be made without departing from the gist of the invention. .

For example, in the embodiment described above, by using a parallel reception method as a reception method for reflected ultrasound waves, it is also possible to obtain a Doppler blood flow image with a high frame rate and less flickering. . Thereby, the amount of information in the displayed image of the blood flow pattern can be increased.

〔effect〕

As explained above, according to the present invention, a set of vectors giving the blood flow direction is set, and based on this, the ultrasonic pulse beam at the measurement point where the blood flow and the ultrasonic pulse beam intersect is added to velocity distribution information. By correcting the velocity data depending on the angle of incidence of blood flow, it is possible to obtain an image of the velocity distribution in the actual direction of blood flow, which allows us to provide organized diagnostic information such as the actual in-vivo velocity distribution image. can do.

This can reduce the risk of misdiagnosis.

[Brief Description of the Drawings] Figures 1 to 6 show a Doppler blood flow image display method according to an embodiment in which the present invention is applied to an ultrasonic diagnostic apparatus that obtains in-vivo information using the ultrasonic pulse Doppler method. 7 to 10 are explanatory diagrams showing blood flow image display images for explaining the principle. FIG. 7 is a block diagram showing a schematic configuration of an ultrasound diagnostic apparatus for implementing the Doppler blood flow image display method, and FIGS. 8 to 10 are displays for explaining this Doppler blood flow image display method. An explanatory diagram showing images, FIG. 11 is a block diagram showing a detailed configuration of an ultrasound diagnostic apparatus that implements the Doppler blood flow image display method of this embodiment, and FIG. 12 is an illustration of the ultrasound diagnostic apparatus shown in FIG. 11. FIG. 13 is an explanatory diagram for explaining the problems of the conventional Doppler blood flow image display method. . In the figure, l: ultrasound probe, 20: image storage device, 60: display correction calculation device, 200: two-dimensional Doppler device, 300: control device.

Claims (10)

[Claims] (1) A means for transmitting an ultrasonic pulse beam into a living body at a constant repetition period, receiving the reflected waves, and displaying a B-mode ultrasound image (hereinafter referred to as a US image); Table means for displaying a motion velocity distribution image of the in-vivo moving part (hereinafter referred to as a Doppler blood flow image) by detecting a frequency shift of a reflected wave subjected to a Doppler shift by the moving part; and a Doppler blood flow image screen. means for freezing the display of the Doppler blood flow image, means for setting an arbitrary vector set on the frozen Doppler blood flow image screen, and velocity distribution information measured at the base point of each vector set by this means in the vector direction. 1. A method for displaying a Doppler blood flow image for an ultrasound diagnostic apparatus, comprising means for correcting the corrected value to a value, and means for displaying a Doppler blood flow image obtained by converting the corrected value into color display information. (2) an ultrasonic probe, a processing unit that performs blood flow velocity distribution calculation to form a Doppler blood flow image by detecting the frequency shift of the reflected wave that has undergone Doppler shift due to in-vivo blood flow; A two-dimensional Doppler device having a display section for displaying the results of the processing section, an image storage device for storing the results of the calculation, and an arbitrary vector set are set on the frozen Doppler blood flow image screen. The Doppler blood flow image according to claim 1, comprising a display correction calculation device that corrects velocity distribution information measured at the base point of each vector to a value in the vector direction, and a control device that controls each of the devices. An ultrasonic diagnostic device that implements the display method. (3) A patent claim in which correction is performed in consideration of blood vessel width by correcting a measurement point on the intersection of the vector and the ultrasonic pulse beam line and a plurality of measurement points before and after each measurement point. The Doppler blood flow image display method for an ultrasound diagnostic apparatus according to item 1. (4) The Doppler blood flow image display method for an ultrasound diagnostic apparatus according to claim 1, wherein the means for freezing the display of the Doppler blood flow image screen uses an image storage device. (5) The means for setting an arbitrary vector set on the frozen Doppler blood flow image screen is performed using a blood flow pattern position specifying device such as a track board, joystick, or light pen. Doppler blood flow image display method for ultrasonic diagnostic equipment. (6) The ultrasonic diagnosis according to claim 1, wherein the means for correcting the velocity distribution information measured at the base point of each set vector into a value in the vector direction is performed using a display correction calculation device. Doppler blood flow image display method for equipment. (7) The means for displaying the Doppler blood flow image obtained by converting the corrected values into color display information is performed using a color encoder and a television monitor. Flow image display method. (8) The processing unit that performs blood flow velocity distribution calculation to form a Doppler blood flow image by detecting the frequency shift of the reflected wave that has undergone Doppler shift due to the in-vivo blood flow, includes a reflection intensity calculation circuit;
An apparatus for implementing the Doppler blood flow image display method according to claim 2, comprising an average velocity calculation circuit and a velocity dispersion calculation circuit. (9) The ultrasonic diagnostic apparatus according to claim 2, wherein the image storage device that stores the results of the calculation includes a reflection intensity calculation memory, an average velocity calculation memory, and a velocity variance calculation memory. (10) The display correction calculation device includes a calculation processing unit, a RAM
The ultrasonic diagnostic apparatus according to claim 2, which comprises a ROM.