JP3052164B2 - Ultrasound diagnostic equipment - Google Patents

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 drawing a difference image, and more particularly, to a function of adding a plurality of difference images to display a velocity vector of a moving part by cumulative processing. For example, the present invention relates to an ultrasonic diagnostic apparatus that facilitates dynamic observation of blood flow.

[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. Hei.
There is -258352 number. Japanese Patent Application Laid-Open No. 62-189054 proposes a method in which a frame component having a large number of planes is displayed, and a motion component is drawn by displaying an image subjected to difference processing between the frames. In Japanese Patent Application No. 1-258352, a method of performing difference processing between images adjacent in time series, a method of performing difference processing of an arbitrary time phase from images arranged in time series, and displaying a difference image in color A method is proposed.

[0003]

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

Accordingly, the present invention solves such a problem, and displays a velocity vector of a moving part by accumulating a plurality of difference images to facilitate, for example, dynamic observation of blood flow. It is an object to provide an ultrasonic diagnostic apparatus.

[0005]

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 at a predetermined cycle by an ultrasonic transmitting / receiving means; In an ultrasonic diagnostic apparatus comprising: means for performing calculation between time-series tomographic images obtained by the tomographic scanning means to generate differential image data thereof; and image display means for displaying the differential image data. Means for adding at least two or more of the above-mentioned difference image data and adding up the image so that the difference image data does not disappear from the added image, and means for supplying the added image to the image display means. is there.

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

[0007]

The ultrasonic transmission / reception means is controlled by the tomographic scanning means, sequentially changes the transmission / reception direction of the ultrasonic wave, and takes in time-series tomographic image data including the moving part from within the subject. Then, the captured tomographic image data is sequentially sent to the difference image data generating means. The difference image data generating means includes:
Using two images of the tomographic image data input in time series,
Subtraction is performed so that those pixel data correspond to each other, and a difference image of one frame is obtained. This scanning is sequentially performed on the images of each time phase to obtain difference images of a plurality of frames arranged in time series. Then, the difference image is added so that the difference image data does not disappear from the added image, and one added difference image is obtained. This processing 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 added difference image, the difference is generated by adding an offset value to one of the tomographic image data when generating the difference image, or by performing weighting when adding the difference image. Use such means.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below 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 the subject 14 and receives ultrasonic waves reflected in the subject 14 by a built-in ultrasonic transducer. is there. Reference numeral 2 denotes an ultrasonic transmission / reception circuit which supplies a driving pulse for transmitting an ultrasonic beam to the ultrasonic transducer and processes a received echo signal. In the same manner as described above, it includes a transmission pulsar, a transmission delay circuit, a reception amplifier, a reception phasing circuit including a 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 an ultrasonic transmission / reception unit. The ultrasonic probe 1 transmits an ultrasonic beam to the subject 14 by a control signal of a controller 13 described later. The body is scanned in a predetermined direction to obtain one (one frame) tomographic image data, and tomographic image data is sequentially obtained in a time series at predetermined time intervals.

Reference numeral 3 denotes an A / D converter for converting an echo signal output from the ultrasonic transmission / reception circuit 2 into a digital signal. Reference numeral 4 denotes a buffer memory for repeating writing and reading of the output signal from the A / D converter 3 for each scanning line or a plurality of scanning lines of the ultrasonic beam, and outputting the same to an image memory (A) 5 described later. . Reference numeral 5 denotes an image memory (A) for storing image data of a plurality of frames as tomographic image data by associating the image data output from the buffer memory 4 with the position or direction of a scanning line of each ultrasonic beam. It comprises a semiconductor memory or the like having a storage capacity capable of storing images. The A / D converter 3, the buffer memory 4, and the image memory (A) 5 constitute a tomographic scanning means, and can repeatedly obtain tomographic image data in the subject 14 at a predetermined cycle. ing.

Reference numeral 6 denotes a subtractor which is a means for performing calculation between time-series tomographic images obtained by the above-described tomographic scanning means and generating differential image data thereof, and is output from the image memory (A) 5. The two frames of tomographic image data 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, and is composed of a semiconductor memory or the like having a storage capacity capable of storing a plurality of frames of images.

Numeral 8 denotes an accumulator for taking in the difference image data of a plurality of frames read from the image memory (B) 7 and accumulating the difference image data, adding at least two pieces of difference image data, and calculating a difference image from the added image. Data is added so that data is not lost. Reference numeral 9 denotes a color encoder for performing color processing on the image data accumulated by the accumulator 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 denotes a D / A converter for converting the image data output from the adder 10 into an analog signal, and 12 denotes a video signal input from the D / A converter 11 to display an image. The display is, for example, a television monitor. The D / A converter 11 and the display 12 constitute an image display unit. Reference numeral 13 denotes a controller that controls the entire operation of each of the above-described components, and includes, for example, a CPU.

Next, the operation of the first embodiment configured as described above will be described. First, an echo signal (analog signal) output from the ultrasonic transmission / reception circuit 2 by transmission / reception of 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. Is done. The buffer memory 4 is composed of a plurality of line memories, and the controller 13 alternately switches the writing and reading each time the ultrasonic wave transmitting / receiving direction changes, and outputs a digital echo signal for each sequentially input ultrasonic receiving beam. Output to the image memory (A) 5. The echo signal input to the image memory (A) 5 is transmitted to the first image storage area in accordance with the control signal of the controller 13 so that the transmission and reception directions of the ultrasonic beams are made to correspond to each other so that one image becomes the first image. Is written so as to form an ultrasonic tomographic image.

When the ultrasonic scanning of one image is completed under the control of the ultrasonic transmission / reception circuit 2, the ultrasonic probe 1 returns the transmission / reception direction to the initial direction again, repeats transmission / reception, and changes the transmission / reception direction. Scanning is performed by sequentially changing each transmission / reception 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 scan to the second image storage area. When the data writing to the second image storage area is completed with the progress of the ultrasonic scanning, a second image is formed.

Next, the controller 13 causes both 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 performs subtraction for each corresponding 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 to 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, and subsequently takes in a third image. The echo signal is A / D converted by the A / D converter 3 and buffered. The 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 out 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 subtracter 6 performs subtraction between the second image and the third image in the same manner as described above, and outputs the difference data. Next, the difference data between the second image and the third image output from the subtracter 6 is written to the second difference image storage area of the image memory (B) 7 controlled by the controller 13.

An arbitrary plurality of difference images obtained in this way are added by the accumulator 8 to obtain an added difference image. The details will be described with reference to FIGS. Figure 2 is a differential image example illustrates the difference image when exercised region has moved on a 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 stationary part becomes “zero”, and for the moving part, the data of the new image side remains as “positive”. The luminance is white, and the data on the old image side is "negative", so that the luminance is displayed in black. That is, as shown in FIG. 3, if the horizontal axis is the position on the straight line l shown in FIG. 2 and the vertical axis is the luminance level of the image, the luminance level of the background (stationary portion) of the image (hereinafter referred to as “background luminance level”) the intensity of a point P ₁ on the basis of the) because white direction, the luminance 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 with time, it is input to the image memory (A) 5 via the A / D converter 3 and the buffer memory 4. FIG. 5 shows the brightness level of each image to be obtained. FIG. 5 shows the same one as FIG. The luminance level after the movement of the motion part P for each frame is displayed in white with higher luminance than the background luminance level. The conventional ultrasonic diagnostic apparatus is configured to visually observe a change in the brightness level of the moving part of each image and confirm that the moving part moves in the direction of the straight line 1 due to an afterimage effect. On the other hand, in the present invention, by performing the following processing, the velocity vector (magnitude and direction) of the moving part is obtained.
Is displayed on the screen. Here, each of the time-series difference images is shown in FIG. 4B to FIG.
To (d) show the luminance level corresponding to each image.

When the accumulator 8 of FIG. 1 performs an accumulating process for an arbitrary plurality of images (three images in this case), the luminance level becomes as shown in FIG. 5 (e). At this time, FIG.
When subtracting the luminance level A position P ₀ from the luminance level A at position P ₁ as shown in, it so subtraction was of the the differential data in subsequent cumulative image disappears, the luminance level of the person who subtracting -A + alpha (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 , respectively, are A and −A + α, and the intermediate positions P ₂ and P ₁ are both + α. Therefore, cumulative difference image, FIG. 4 (e), the position P ₃ is the white level of one end, the position P ₀ of the other end becomes the brightness level close to black level, an intermediate position P ₂ and P ₁
Is a value close to the background luminance level. Therefore, the observer obtains the single cumulative difference image shown in FIG.
It is possible to know the direction (vector) of the moving part.

Embodiment 2 In the above description, as shown in FIGS. 5 (b) to 5 (d), the respective difference images are cumulatively added with the same weight. However, the present invention is not limited to this. May be added with arbitrary different weights. FIG. 6 is a block diagram of the internal configuration showing an embodiment of another accumulator circuit 8 'in the case of accumulating each difference image with different weights.
The cumulative circuit 8 'are selected one by n pieces of difference image data Is ₀ ~Is (n-1) new 3 data input of which time series of the image memory (B) 7 shown in FIG. 1 Output And a first switch 15 for shifting the difference image data inputted for each addition process one by one, and three data from the first switch 15 and different predetermined weighting factors for each data. a multiplier 16 that multiplies β ₁ , β ₂ , and β ₃ and arbitrarily assigns different weights;
A accumulator 17 for inputting and accumulating the three data weighted by the accumulator 17, and a second switch 18 for sequentially distributing the data accumulatively processed by the accumulator 17 to (n-1) outputs for each accumulative processing. the second distributed output by switching unit 18 (n-1) piece of cumulative difference image data Ias ₀ ~Ias (n
-2) is stored. In FIG. 6, reference numeral 5 denotes n pieces of tomographic image data I ₀ to I ₀ .
5 shows an image memory (A) that stores In. Also,
In FIG. 6, the subtracter 6 shown in FIG. 1 is not shown.

Next, the operation of the accumulating circuit 8 'having such a configuration will be described. First, the image data 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 the image memory (B) 7 is supplied to the first switch 15. The first switch 15 selects an arbitrary number of new image data in time series, for example, three pieces of differential image data, and sends it to the next multiplier 16. Then, the multiplier 16 multiplies each 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 an accumulating process. Then, the accumulated difference image data is
The second switch 18 sequentially (n-
1) Distributed to output. Then, the distributed output of the (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 manner, the cumulative difference image is obtained by the cumulative circuit 8 'as shown in FIG. As this cumulative process, and therefore is sequentially executed in time series, as shown in FIG. 7, changes from time t = t ₁ to time t = t _5,
The cumulative difference image changes as shown in FIGS. The luminance level of the cumulative difference image thus obtained is changed to 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 an adder 10, converted into an analog signal by a D / A converter 11, and
Is displayed on the screen.

Embodiment 3 Next, a third embodiment of the present invention will be described. In the third embodiment, the vector display according to the first embodiment is continuously performed. FIG. 8 shows a configuration in which the configuration shown in FIG. 1 is modified such that the addition of the difference images is performed for each designated number of images and the added difference images are further added. That is, the difference image addition number setting device 20 is connected to the controller 13, and an image memory (C) 21 is provided downstream of the accumulator 8. The difference image addition number setting unit 20 outputs the difference images of a plurality of frames stored in the image memory (B) 7 to the accumulator 8 in order of the set number of frames. The image memory (C) 21 stores an accumulated difference image added by the accumulator 8 and added with hue information by the color encoder 9, and is constituted by, for example, a plurality of frame memories. A plurality of differently added cumulative difference images can be stored.

Next, the display mode of the difference image in the third embodiment will be described with reference to FIG. FIG. 9A shows tomographic images P ₀ , P at each time from time t ₀ to time tn.
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 given by a command from the controller 13 as shown in FIG.
(B) in a similar manner as shown in ~ (d), for example, P ₀ and P _1, P ₁ and P _2, P ₂ and P _3, ..., between Pn-1 and the tomographic image of the front and rear as Pn A difference image is generated for each. These difference images are stored in the image memory (B) 7.

Next, when reading the difference image from the image memory (B) 7, the difference image addition number setting unit 20 is used.
The controller 13 repeatedly reads the designated number of difference images. That is, assuming that the operator sets, for example, three images to the difference image addition number setting device 20, _first , P ₀ , P ₁ ,
The three difference images formed from P ₂ and P ₃ are read out,
The accumulator 8 creates the accumulative difference image shown in FIG. 9B by the accumulator 8, and gives the color encoder 9, for example, red hue information to the image memory (C) 21.
Is output to the first storage area. Next, the three difference images formed from P ₄ , P ₅ , P ₆ , and P ₇ are read from the image memory (B) 7, and the accumulator 8 calculates the accumulative difference image shown in FIG. It is created, color information is given according to the green hue, and 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 different hue from the first. The reason is to make it easy to identify each vector when the vectors are continuously displayed. Hereinafter, similarly, the difference images are read out from the image memory (B) 7 in chronological order and added together, and the hue information is stored in the image memory (C) 21 with different hue information.

Next, 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 12. The display mode will be described below. The first display mode is shown in FIG.
As shown in the figure, the cumulative difference image in each storage area of the image memory (C) 21 is read out at a time and displayed. In the image according to this display method, a plurality of vectors according to the first embodiment are continuously displayed. 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 a blood flow site, a blood cell flow layer can be identified in a vector manner.

In the second display mode, each cumulative difference image is displayed over time for a predetermined 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 converted by the display time setting unit 22 connected to the controller 13 in FIG. At the designated time t ₁ ′ to t ₄ ′, the T time is repeatedly read out and displayed, and then the cumulative difference image composed of P _{4 to} P ₇ is repeatedly read out for the T time designated by the display time setting unit 22. Then, the cumulative difference image is displayed over time in the same manner. According to this display mode, unlike the first display mode, only vectors within a certain time are displayed at predetermined time intervals. Therefore, it is possible to make a deep observation of only the vector.

It is apparent from FIG. 8 that the tomographic image may be combined with the cumulative difference image as a background image in the third embodiment.

[0030]

The present invention has been configured as described above.
The accumulating means (8, 8 ') adds at least two or more difference images of a plurality of frames arranged in chronological order obtained by the difference image data generating means (6), and obtains difference image data from the added images. Image display means (11, 12) for obtaining time-sequential cumulative difference images by accumulating so as not to disappear
Can be displayed. Therefore, the velocity vector (the magnitude and direction of the 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. For this reason, the diagnostic performance of the ultrasonic diagnostic apparatus can be improved, and the clinical value can be increased.

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 a blood flow site, a blood cell flow layer can be identified in a vector manner.

[Brief description of the 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 an obtained difference image;

FIG. 3 is an explanatory diagram showing a change in a luminance 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 over time;

FIG. 5 is an explanatory diagram showing a change in luminance 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 accumulating means;

FIG. 7 is an explanatory diagram showing a state in which the cumulative difference image changes with time in the case of the embodiment in FIG. 6;

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

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

FIG. 10 is an explanatory diagram showing a mode in which an accumulated difference image is displayed over time for 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.

────────────────────────────────────────────────── ─── of the front page continued (72) inventor Makoto Moto Osamu Chiba Prefecture shore Kashiwa Shintoyofuta No. 2 No. 1 Co., Ltd. Hitachi Medical intra-technology research Institute (58) investigated the field (Int.Cl. ^7, DB name) A61B 8/00-8/15

Claims (2)

(57) [Claims] 1. A tomographic scanning unit that repeatedly obtains tomographic image data in a subject by a predetermined period by an ultrasonic transmitting / receiving unit, and a calculation is performed between time-series tomographic images obtained by the tomographic scanning unit to calculate a difference between them. In an ultrasonic diagnostic apparatus comprising: means for generating image data; and image display means for displaying the difference image data, at least two or more of the plurality of difference image data are added, and difference image data is obtained from the added image. An ultrasonic diagnostic apparatus comprising: means for accumulating the accumulated image so as not to disappear; and means for supplying the accumulated image to the image display means. 2. A means for adding two or more difference image data and adding the difference image data so that the difference image data does not disappear from the added image is provided with means for setting the number of the difference images to be added. 2. An ultrasonic diagnostic apparatus according to claim 1, further comprising means for storing an accumulated difference image accumulated by said accumulating means.