JPH0531112A - Ultrasonic diagnostic system - Google Patents

Abstract

PURPOSE:To display a velocity vector of a moving part, for example, facilitate dynamic observation of a blood vessel by performing an accumulation processing of a plurality of differential images in an ultrasonic diagostic system. CONSTITUTION:An accumulator 8 is provided to perform an accumulation so that at least two images or more are added in a differential image data generated and outputted from a subtracter 6 while the differential image data does not vanish from the images added and the image data subjected to the accumulation processing with the accumulator 8 undergoes a color processing with a color encoder 9. Moreover, a differential image colored and a black and white tomographic image are overlapped with an adder 10 to be supplied to a D/A converter 11 and a display device 12 as image display means. Thus, the accumulation processing of a plurality of differential images is accomplished to display a velocity vector of a moving part.

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 having a function of rendering a difference image, and in particular, has a new function of displaying a velocity vector of a moving part by cumulatively processing a plurality of difference images. The present invention relates to an ultrasonic diagnostic apparatus which is provided and facilitates observation of blood flow dynamics.

[0002]

2. Description of the Related Art A conventional ultrasonic diagnostic apparatus having a function of rendering a difference image is disclosed in Japanese Patent Application Laid-Open No. 62-189054 or Japanese Patent Application No.
-There is No. 258352. Japanese Unexamined Patent Publication No. Sho 62-189054 proposes a method of rendering a motion component by having a frame memory of a large number of planes and displaying an image subjected to difference processing between the frames. Also, in Japanese Patent Application No. 1-258352, a method of performing difference processing between images that are adjacent in time series, a method of performing difference processing of an arbitrary time phase from images arranged in time series, and a difference image are displayed in color. Proposing a method.

[0003]

In the above-mentioned prior art, the difference processing is performed using the tomographic image data, and the difference image is
It was only displayed for each frame, and cumulative processing of a plurality of difference images was not performed. Therefore, the velocity vector (magnitude and direction of velocity) of the moving part cannot be displayed, and, for example, dynamic observation of blood flow cannot be performed.

Therefore, the present invention solves such a problem and displays the velocity vector of the motion site by cumulatively processing a plurality of difference images, thereby facilitating the dynamic observation of blood flow, for example. It is an object to provide an ultrasonic diagnostic apparatus.

[0005]

In order to achieve the above object, an ultrasonic diagnostic apparatus according to the present invention comprises a tomographic scanning means for repeatedly obtaining tomographic image data in a subject by an ultrasonic wave transmitting / receiving means at a predetermined cycle. A plurality of ultrasonic diagnostic apparatuses are provided, each including: a unit that performs calculation between time-series tomographic images obtained by the tomographic scanning unit to generate differential image data thereof; and an image display unit that displays the differential image data. And adding means for adding at least two images of the difference image data and accumulating so as not to lose the difference image data from the added images, and means for supplying the added image to the image display means. is there.

In addition to the means for adding two or more images of the difference image data and cumulatively adding the difference image data so that the difference image data does not disappear from the added images, a means for setting the number of the difference images to be added is provided. It is effective to provide means for storing the cumulative difference image cumulatively added by the cumulative addition means.

[0007]

The ultrasonic wave transmitting / receiving means is controlled by the tomographic scanning means, the ultrasonic wave transmitting / receiving direction is sequentially changed, and the tomographic image data including the motion site is captured in time series from the inside of the subject. Then, the captured tomographic image data is sequentially sent to the difference image data generating means. The difference image data generation means is
Using two images of tomographic image data input in time series,
Subtraction is performed so that the pixel data correspond to each other to obtain a one-frame difference image. This scanning is sequentially performed on the images of each time phase to obtain the difference images of a plurality of frames arranged in time series. Then, the differential images are cumulatively added so that the differential image data does not disappear from the cumulatively added images to obtain one cumulative differential image. This process is sequentially performed in time series, and the cumulative difference image is displayed on the image display means. In order to prevent the difference image data from disappearing from the accumulated difference images, an offset value is added to one tomographic image data at the time of generating the difference image to perform the difference, or a weighting is performed at the time of accumulating the difference images. Use such means.

[0008]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

Embodiment 1 FIG. 1 is a block diagram showing a first embodiment of the present invention.
In FIG. 1, reference numeral 1 denotes an ultrasonic probe, which transmits an ultrasonic beam to a subject 14 and receives ultrasonic waves reflected inside the subject 14 by an ultrasonic transducer incorporated therein. is there. Reference numeral 2 denotes an ultrasonic transmission / reception circuit, which supplies a drive pulse for transmitting an ultrasonic beam to the ultrasonic transducer and processes a received echo signal. Similarly, it is configured to include a wave transmission pulser, a wave transmission delay circuit, a wave reception amplifier, a wave reception phasing circuit including a wave reception delay circuit and an adder, a TGC circuit, a detection circuit, and the like. The ultrasonic probe 1 and the ultrasonic transmission / reception circuit 2 constitute ultrasonic transmission / reception means, and the ultrasonic probe 1 transmits an ultrasonic beam to the subject 14 according to a control signal from a controller 13 described later. The body is scanned in a predetermined direction to obtain tomographic image data for one sheet (one frame), and tomographic image data is sequentially obtained at predetermined time intervals in time series.

Reference numeral 3 is an A / D converter for converting the echo signal output from the ultrasonic wave transmitting / receiving circuit 2 into a digital signal. A buffer memory 4 repeats writing and reading of the output signal from the A / D converter 3 for each scanning line of the ultrasonic beam or for each scanning line, and outputs the signals to an image memory (A) 5 described later. . Reference numeral 5 denotes an image memory (A) that stores image data of a plurality of frames as tomographic image data by correlating the image data output from the buffer memory 4 with the position or direction of the scanning line of each ultrasonic beam. It is composed of a semiconductor memory or the like having a storage capacity capable of storing images. Then, the A / D converter 3, the buffer memory 4, and the image memory (A) 5 constitute a tomographic scanning means, and the tomographic image data in the subject 14 is repeatedly obtained at a predetermined cycle. ing.

Reference numeral 6 denotes a subtracter which is a means for performing calculation between the time-series tomographic images obtained by the tomographic scanning means and generating difference image data thereof, which is output from the image memory (A) 5. The tomographic image data of the two frames corresponding to each other are subtracted by associating the pixel addresses with each other, and the difference data is output. Reference numeral 7 denotes an image memory (B) for storing the difference image data generated by the subtractor 6, which is composed of a semiconductor memory or the like having a storage capacity capable of storing images of a plurality of frames.

Reference numeral 8 denotes an accumulator that takes in the differential image data of a plurality of frames read from the image memory (B) 7 and performs cumulative processing, adds at least two differential image data, and subtracts the differential image from the added image. It is designed to be cumulative so that data is not lost. Reference numeral 9 denotes a color encoder for color-processing the image data cumulatively processed by the cumulative adder 8. Reference numeral 10 denotes an adder for superimposing and displaying the difference image colorized by the color encoder 9 and the black and white tomographic image read from the image memory (A) 5.

Reference numeral 11 is a D / A converter for converting the image data output from the adder 10 into an analog signal, and 12 is a video signal input from the D / A converter 11 for image display. It is a display device, such as a television monitor. The D / A converter 11 and the display 12 constitute an image display means. Reference numeral 13 is a controller that controls the overall operation of each of the above-described components, and is composed of, for example, a CPU.

Next, the operation of the first embodiment thus constructed will be described. First, an echo signal (analog signal) output from the ultrasonic transmitting / receiving circuit 2 by transmitting / receiving an ultrasonic beam from the ultrasonic probe 1 is converted into a digital signal by the A / D converter 3 and output to the buffer memory 4. To be done. The buffer memory 4 is composed of a plurality of line memories, and writing and reading are alternately switched by the controller 13 each time the ultrasonic wave transmission / reception direction changes, and a digital echo signal is sequentially output for each ultrasonic wave reception beam. Output to the image memory (A) 5. The echo signal input to the image memory (A) 5 is sequentially transferred to the first image storage area by the control signal of the controller 13 for each ultrasonic beam, and the transmission and reception directions thereof are made to correspond to each other to form a first image. Is written so as to form an ultrasonic tomographic image of.

The ultrasonic probe 1 returns the transmitting / receiving direction to the initial direction again when the ultrasonic scanning for one image is completed under the control of the ultrasonic transmitting / receiving circuit 2, repeats transmitting / receiving, and changes the transmitting / receiving direction. Scanning is performed by sequentially changing each transmitted / received wave. Therefore, the echo signal is also A / D converted by the A / D converter 3 and output to the image memory (A) 5 via the buffer memory 4 in the same manner as described above. The image memory (A) 5 is controlled by the controller 13 so as to write the echo signal captured by the current scanning into the second image storage area. When the data writing to the second image storage area is completed with the progress of the ultrasonic scanning, the second image is formed.

Next, the controller 13 causes the pixels of the respective images to correspond to each other from the first image storage area and the second image storage area, and causes both image data to be read out,
Output to the subtractor 6. The subtracter 6 subtracts each correspondingly input data (pixel data) and sequentially outputs difference data between the first image and the second image. Next, the difference data between the first image and the second image output from the subtractor 6 is written in the first difference image storage area of the image memory (B) 7 controlled by the controller 13.

Next, the ultrasonic probe 1 continues to perform tomographic scanning after that, and subsequently captures the third image, and the echo signal is A / D converted by the A / D converter 3 and buffered. Data is sequentially written to the third image storage area of the image memory (A) 5 via the memory 4. And the third
An image is formed. When the formation of the third image is completed, the controller 13 causes the pixel data to be read from the second image storage area and the third image storage area in association with each other, and outputs them to the subtractor 6. Then, the subtractor 6 subtracts between the second image and the third image, and outputs the difference data, as described above. Next, the difference data between the second image and the third image output from the subtractor 6 is written in the second difference image storage area of the image memory (B) 7 controlled by the controller 13.

The arbitrary difference images thus obtained are cumulatively added by the accumulator 8 to obtain a cumulative difference image. The details will be described with reference to FIGS. FIG. 2 is an example of a difference image, and shows a difference image when the motion site moves on the straight line l from the position P ₀ to the position P ₁ . At this time, by subtracting the temporally old image from the temporally new image, the difference value of the static portion becomes “zero”, and for the moving part, the data on the new image side remains as “positive”. The brightness is white, and the data on the old image side is "negative", so the brightness is displayed in black. That is, as shown in FIG. 3, assuming that the horizontal axis is the position on the straight line 1 shown in FIG. 2 and the vertical axis is the brightness level of the image, the brightness level of the background (still part) of the image (hereinafter referred to as “background brightness level”). That is, the brightness of the point P ₁ is displayed in the white direction and the brightness of the point P ₀ is displayed in the black direction.

Further, as shown in FIG. 4, when the moving part moves from P ₀ to P ₃ over time, the data is input to the image memory (A) 5 through the A / D converter 3 and the buffer memory 4. FIG. 5 shows the brightness level of each image formed. FIG. 5 shows the same as FIG. The brightness level after the movement of the motion part P for each frame is displayed in white, which has a higher brightness than the background brightness level. The conventional ultrasonic diagnostic apparatus visually observes the change in the brightness level of the moving part for each image and confirms that the image is moving in the direction of the straight line 1 due to the afterimage effect. On the other hand, in the present invention, the velocity vector (size and direction) of the motion part is obtained by performing the following processing.
Is displayed on the screen. Here, from FIG. 4B to FIG. 4D, time-series difference images are shown in FIG.
1 to (d) show the brightness level corresponding to each image.

When the accumulator 8 of FIG. 1 performs accumulative processing of arbitrary plural images (three images in this case), the luminance level becomes as shown in FIG. 5 (e). At this time, the same figure (b)
As shown in, when subtracting the brightness level A at the position P ₀ from the brightness level A at the position P ₁ , if the subtraction is performed as it is, the difference data disappears in the subsequent cumulative image. Therefore, the brightness level of the subtracted one is −A + α. (Α is an offset). Therefore, the luminance level of the cumulative difference image obtained from the three difference images is as shown in FIG.
Corresponding to the positions P ₃ and P ₀ , A and −A + α are obtained respectively, and the intermediate positions P ₂ and P ₁ are both + α. Therefore, in the cumulative difference image, as shown in FIG. 4E, the position P _{3 at} one end has a brightness level close to the white level, and the position P ₀ at the other end has a brightness level close to the black level, and P ₂ and P _{1 at} intermediate positions.
The luminance level of is close to the background luminance level. Therefore, the observer uses the single cumulative difference image of FIG.
It is possible to know the direction (vector) of the movement site.

Embodiment 2 In the above description, as shown in FIGS. 5B to 5D, the difference images are cumulatively added with equal weighting, but the present invention is not limited to this and each difference image is added. May be cumulatively added with arbitrary weighting. FIG. 6 is a block diagram of an internal configuration showing another embodiment of the cumulative addition circuit 8'when the differential images are cumulatively processed with different weights.
This accumulator circuit 8'inputs n pieces of difference image data Is _{0 to} Is (n-1) from the image memory (B) 7 shown in FIG. 1, selects three new data in time series, and outputs them. In addition, the first switching device 15 for shifting the differential image data input for each cumulative processing by one data, and the three data from the first switching device 15 are input, and different predetermined weight coefficients are applied to the respective data. A multiplier 16 for multiplying β ₁ , β ₂ , and β _{3 and} giving arbitrary different weights, and this multiplier 16
An accumulator 17 for inputting and cumulatively adding the three data weighted by, and a second switcher 18 for sequentially distributing the data cumulatively processed by the cumulative accumulator 17 to the (n-1) output for each cumulative processing. , (N-1) cumulative difference image data Ias _{0 to} Ias (n) distributed and output by the second switch 18.
-2) is stored in the cumulative difference image memory 19. In FIG. 6, reference numeral 5 is n tomographic image data I ₀ to.
The image memory (A) which stores In is shown. Also,
6, the subtractor 6 shown in FIG. 1 is omitted.

Next, the operation of the cumulative circuit 8'having such a configuration will be described. First, the image data that has been subjected to the difference processing by the subtractor 6 shown in FIG. 1 is stored in the image memory (B) 7, and the difference image data read from this image memory (B) 7 is the first switch 15 The first switch 15 selects a new arbitrary number of pieces of difference image data in time series, for example, three pieces of difference image data, and sends them to the next multiplier 16. Then, the multiplier 16 multiplies the respective difference image data by different weight coefficients β ₁ , β ₂ , and β ₃ . Next, the difference image data thus weighted differently is input to the accumulator 17 and subjected to the accumulating process. After that, the difference image data subjected to the cumulative processing is
The second switching unit 18 sequentially (n-
1) It is distributed to the output. Then, the distributed output (n-1) cumulative difference image data is stored in the next cumulative difference image memory 19. Thereafter, the cumulative difference image data is read from the cumulative difference image memory 19,
It is sent to the color encoder 9 shown in FIG.

In this way, the cumulative difference image is obtained by the cumulative circuit 8'as shown in FIG. 4 (e). Since this cumulative processing is sequentially executed in time series, as shown in FIG. 7, as time t = t ₁ changes to time t = t ₅ ,
The cumulative difference image changes from (b) to (f) in FIG. The luminance level of the cumulative difference image thus obtained is changed to the hue by the color encoder 9. Then, the color image and the ultrasonic black-and-white image output from the image memory (A) 5 are added by the adder 10, converted into an analog signal by the D / A converter 11, and the display 12
The image is displayed on.

Third Embodiment Next, a third embodiment of the present invention will be described. The third embodiment continuously performs the vector display according to the first embodiment. FIG. 8 shows a modification of the configuration shown in FIG. 1 so that the difference images are added for each designated number of sheets and the added difference images are further accumulated. That is, the difference image addition number setting device 20 is connected to the controller 13, and the image memory (C) 21 is provided in the subsequent stage of the accumulator 8. The difference image addition number setting device 20 outputs the difference images of a plurality of frames stored in the image memory (B) 7 to the accumulator 8 in order by the set number of frames. The image memory (C) 21 stores the cumulative difference image that is cumulatively added by the accumulator 8 and the hue information is added by the color encoder 9. The image memory (C) 21 is composed of, for example, a plurality of frame memories. It is possible to store a plurality of cumulative difference images that are physically different.

Next, the display mode of the difference image in the third embodiment will be described with reference to FIG. FIG. 9A shows a tomographic image P ₀ at each time from time t ₀ to time t n,
P _1, P _2, ..., it indicates the Pn, these tomographic images P ₀ to PN
Are stored in the image memory (A) 5. These tomographic images P _{0 to} Pn are generated by the controller 13 as shown in FIG.
In the same manner as shown in (b) to (d), for example, P ₀ and P ₁ , P ₁ and P ₂ , P ₂ and P ₃ , ..., Pn-1 and Pn between front and back tomographic images. A difference image is generated for each. The difference images are stored in the image memory (B) 7.

Next, when the difference image is read from the image memory (B) 7, the difference image addition number setting unit 20 is set.
Command, the controller 13 repeatedly reads out the specified number of difference images. That is, if the operator sets, for example, three in the difference image addition number setting unit 20, first, the image memories (B) 7 to P ₀ , P ₁ ,
The three difference images formed by P ₂ and P ₃ are read out,
After the cumulative difference image shown in FIG. 9B is created by the cumulative adder 8 and the hue information of red, for example, is added to the cumulative difference image by the color encoder 9, the image memory (C) 21
Is output to the first storage area of the. Next, the three difference images formed by P ₄ , P ₅ , P ₆ , and P ₇ are read from the image memory (B) 7, and the cumulative difference image shown in FIG. It is created, color information is added by the hue of green, and the color information is output to the second storage area of the image memory (C) 21. The hue information given to the second cumulative difference image is preferably a hue different from that of the first. The reason is to facilitate the identification of each vector when the vectors are continuously displayed. In the same manner, the difference images are sequentially read from the image memory (B) 7 three by three in a time series and accumulated, and the hue information is stored in the image memory (C) 21 differently.

Then, the cumulative difference image is read out from the image memory (C) 21 as follows, D / A converted by the D / A converter 11 and displayed on the display unit 12. The display mode will be described below. The first display mode is shown in FIG. 9 (s).
As shown in, the cumulative difference image in each storage area of the image memory (C) 21 is read out at once and displayed. A plurality of vectors according to the first embodiment are continuously displayed on the image by this display method. Then, by appropriately setting the number of added difference images, the moving direction and speed of the moving tissue can be easily identified. In particular, when this display mode is used for the blood flow site, the blood cell flow layer can be identified in a vector manner.

The second display mode is to display each cumulative difference image for a predetermined period of time. As shown in FIG. 10, first, the cumulative difference image composed of P _{0 to} P ₃ in the first storage area of the image memory (C) 21 is displayed by the display time setting device 22 connected to the controller 13 in FIG. At the designated times t ₁ ′ to t ₄ ′, T times are repeatedly read out and displayed, and then the cumulative difference image consisting of P _{4 to} P ₇ is repeatedly read out for the T times also designated by the display time setting unit 22 and read out. Then, the cumulative difference image is displayed over time. According to this display mode, unlike the first display mode, only the vector within a certain time is displayed for each predetermined time. Therefore, it is possible to make a deep observation on only that vector.

It is apparent from FIG. 8 that the tomographic image may be combined and displayed as the background image on the cumulative difference image also in the third embodiment.

[0030]

Since the present invention is constructed as described above,
The cumulative addition means (8, 8 ') adds at least two difference images of a plurality of frames arranged in time series obtained by the difference image data generation means (6), and the difference image data is obtained from the added images. Image display means (11, 12) by cumulatively adding so as not to disappear to obtain a time-series cumulative difference image
Can be displayed on. Therefore, the velocity vector (magnitude and direction of velocity) of the moving part of the subject can be displayed as an image, and, for example, dynamic observation of blood flow can be easily performed in real time. From this, the diagnostic ability of the ultrasonic diagnostic apparatus can be improved and the clinical value can be increased.

Further, according to the third embodiment shown in FIG.
By appropriately setting the number of added difference images, the moving direction and speed of the moving tissue can be easily identified. In particular, at the blood flow site, the layer of blood cell flow can be identified in a vector manner.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention,

FIG. 2 is an explanatory diagram showing an example of the obtained difference image,

FIG. 3 is an explanatory diagram showing a change in a brightness level of an image at a position on a linear movement;

FIG. 4 is an explanatory diagram showing a state in which a moving part moves on a certain straight line with time,

FIG. 5 is an explanatory diagram showing changes in the brightness level of an image at each position input to the image memory (A) in the case of FIG. 4;

FIG. 6 is a block diagram of an internal configuration showing a second embodiment of the cumulative addition means,

7 is an explanatory diagram showing a state in which the cumulative difference image changes with the change of time in the case of the embodiment of FIG.

FIG. 8 is a block diagram showing a third embodiment of the present invention,

FIG. 9 is an explanatory view showing a display mode of a difference image in the third embodiment,

FIG. 10 is an explanatory diagram showing a mode in which cumulative difference images are displayed over time by a predetermined time in the third embodiment.

[Explanation of symbols]

1 ... Ultrasonic probe, 2 ... Ultrasonic transmission / reception circuit, 3 ... A
/ D converter, 4 ... Buffer memory, 5 ... Image memory (A), 6 ... Subtractor, 7 ... Image memory (B), 8
... accumulator, 8 '... accumulator circuit, 9 ... color encoder, 10 ... adder, 11 ... D / A converter, 12 ...
Display device, 14 ... Subject, 20 ... Difference image addition number setting device, 21 ... Image memory (C), 22 ... Display time setting device.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toshio Ogawa             2-11 Shinjuyo, Kashiwa-shi, Chiba Japan Co., Ltd.             Tate Medico Research Institute (72) Inventor Makoto Kishimoto             2-11 Shinjuyo, Kashiwa-shi, Chiba Japan Co., Ltd.             Tate Medico Research Institute

Claims (2)

[Claims] 1. A tomographic scanning means for repeatedly obtaining tomographic image data in a subject by an ultrasonic wave transmitting / receiving means at a predetermined cycle, and a time series tomographic image obtained by this tomographic scanning means is calculated, and a difference between them is calculated. In an ultrasonic diagnostic apparatus including a unit for generating image data and an image display unit for displaying the difference image data, at least two images or more of the plurality of difference image data are added, and the difference image data is added from the added images. Is provided so as not to disappear, and means for supplying the accumulated image to the image display means. 2. The means for adding two or more images of the difference image data and accumulating means for accumulating the difference image data so that the difference image data does not disappear from the added images is provided with a means for setting the number of the difference images to be added, The ultrasonic diagnostic apparatus according to claim 1, further comprising means for storing the cumulative difference image cumulatively added by the cumulative addition means.