JPH0538340A - Ultrasonic diagnostic device - Google Patents

Abstract

PURPOSE:To draw the movement of the motion parts such as the heart, veins, and blood flow in an inspected body, and draw a motion state only in a related region set in a tomogram. CONSTITUTION:A related region consisting of an arbitrary drawing in a closed loop is set in a tomogram displayed on a TV monitor 8 by a related region setting device 9, and difference calculation is carried out by a susbtractor 6 only between the image data in the related region which is set by the related region setting device 9. Accordingly, a difference image is displayed only for the inside of the related region set in the tomogram about the diagnosing part of an inspected body, and the motion state is drawn, having the tomogram as back figure.

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 for obtaining a tomographic image of a diagnostic region of a subject by using ultrasonic waves, and particularly to a heart, blood vessel and blood flow in the subject without using a contrast agent. It is possible to visualize the movement of movement parts such as
The present invention relates to an ultrasonic diagnostic apparatus capable of depicting a motion state only in a region of interest set in a tomographic image.

[0002]

2. Description of the Related Art A method of displaying an image of a blood flow, a heart or the like in a subject in real time using ultrasonic waves is a B mode display,
Although Doppler mode display is known, the latest method is to obtain difference images by calculating between ultrasonic tomographic images, British Heart Journal 59 (1988).
Pages 12 to 19 (British Heart Journal 59 (1988) PP
12-19). In this method, a contrast agent is used to perform subtraction between tomographic images before and after the injection of the contrast agent so that, for example, a region of interest of the heart can be observed with contrast.

That is, according to this image display method, as shown in FIG.
As shown in FIG. 1, first, before injecting a contrast agent into a subject, an ultrasonic tomographic image is captured, for example, in four frames, and
The images of the frames are added and averaged to create a mask image, and then a contrast agent is injected into the subject, and a tomographic image is captured with time from the time when the contrast agent reaches the diagnostic site. A method is used in which subtraction is performed with each tomographic image after injection to sequentially obtain difference images. In this method, the density of each pixel of the mask image is the average value of the density of the corresponding pixels of the four frames. The reason for this is to reduce the influence of random noise on the difference image and to obtain a better difference image.

[0004]

However, in the image display by such a conventional ultrasonic diagnostic apparatus, a contrast agent is injected into the blood of a subject, and a place where the blood moves, such as a ventricle or an atrium, is contrasted. Therefore, it is difficult to obtain motion information of a region with a small blood flow, for example, the tissue itself. Moreover, although the motional state of the inner wall of the ventricle and the atrium can be grasped, the motional state of the outer wall cannot be observed. Further, since the contrast agent is injected into the subject, it cannot be applied to a person who cannot withstand it.

Further, as shown in FIG. 6, since a difference image is obtained by performing subtraction between the entire one mask image and each tomographic image after the injection of the contrast agent, each of the obtained individual images is obtained. In the difference image, only the motion component is displayed, and the static part such as the contour is not displayed, and it is difficult to understand the relation of the motion of the motion part in the entire diagnosis part. Therefore, the tomographic image showing the whole must be observed separately, which makes diagnosis difficult.

Therefore, the present invention addresses such a problem, makes it possible to depict the movement of a moving part in the subject without using a contrast agent, and only in the region of interest set in the tomographic image. An object of the present invention is to provide an ultrasonic diagnostic apparatus that can visualize a motion state.

[0007]

In order to achieve the above object, an ultrasonic diagnostic apparatus according to the present invention comprises an ultrasonic wave transmitting / receiving means for transmitting and receiving an ultrasonic wave to a subject, and a reflection from the ultrasonic wave transmitting / receiving means. Tomographic scanning means that repeatedly obtains tomographic image data in a subject including a moving tissue using an echo signal at a predetermined cycle, and a difference calculation is performed between the time-series images obtained by this tomographic scanning means to obtain the difference images. In an ultrasonic diagnostic apparatus having a means for generating data and an image display means for displaying the difference image data from the difference image data generating means, from a closed loop arbitrary figure in the tomographic image displayed on the image display means. A region of interest setting means for setting a region of interest, and the difference image data generating means is provided only between the image data in the region of interest set by the region of interest setting means. Ri is provided with a processing unit to perform the differential operation.

Further, a storage means for storing the generated difference image data of the region of interest is provided on the output side of the difference image data generating means, and the output side of this storage means is
A single image is obtained by adding the differential image data of the region of interest from the storage means and the tomographic image data obtained by removing the image data of the region of interest from the tomographic image data used to generate the differential image data of the region of interest. It is effective to provide a means for displaying as.

[0009]

In the ultrasonic diagnostic apparatus constructed as described above, the region of interest setting means sets the region of interest composed of a closed loop arbitrary figure in the tomographic image displayed on the image display means,
The processing means operates so that the difference image data generation means performs the difference calculation only between the image data in the interest area set by the interest area setting means. As a result, the difference image is displayed only within the region of interest set in the tomographic image of the diagnostic region of the subject, and the motion state can be visualized with the tomographic image as the back.

[0010]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing an embodiment of an ultrasonic diagnostic apparatus according to the present invention. This ultrasonic diagnostic apparatus obtains a tomographic image of a diagnostic region of a subject using ultrasonic waves, and as shown in the figure, a probe 1, a transmitting circuit 2, a receiving circuit 3, and a video. Signal processing circuit 4 and digital scan converter (hereinafter abbreviated as "DSC")
5, a subtractor 6, a D / A converter 7, and a television monitor 8
And a region of interest setting device 9 and an address comparator 10.

The probe 1 mechanically or electronically performs beam scanning to transmit and receive ultrasonic waves to the subject. Although not shown, the probe 1 is a source of ultrasonic waves. A transducer that receives the reflected echo is built in.
The wave transmission circuit 2 generates a wave transmission pulse for driving the probe 1 to generate an ultrasonic wave, and also has a convergence point of the ultrasonic wave transmitted by a built-in wave phasing circuit at a certain depth. To be set to. In addition, the receiving circuit 3 is the probe 1
The signal of the reflected echo received at is amplified by a predetermined gain and the phase thereof is controlled by a built-in wave phasing circuit to form an ultrasonic beam at one or a plurality of converging points. Further, the video signal processing circuit 4 receives the received signal from the receiving circuit 3 and performs signal processing such as gain correction, log compression, detection, contour enhancement, and filter processing. Then, these probe 1 and the wave transmission circuit 2
The receiving circuit 3 and the video signal processing circuit 4 as a whole constitute an ultrasonic wave transmitting / receiving means, and the probe 1 scans the ultrasonic beam in a certain direction in the body of the subject.
One tomographic image is obtained.

The DSC 5 obtains tomographic image data in the subject including the moving tissue in the ultrasonic wave transmission cycle by using the reflected echo signal output from the video signal processing circuit 4 of the ultrasonic wave transmitting / receiving means, and this data is obtained. An A / D converter 11 for converting the reflected echo signal from the video signal processing circuit 4 into a digital signal, which serves as a means for reading out in synchronism with the television for displaying and a means for controlling the system.
And a plurality of frame memories 12 for storing the tomographic image data digitized by the A / D converter 11 in time series.
a, 12b, ..., 12n and these frame memories 1
2a to 12n, an ultrasonic wave transmission synchronization circuit 13 that generates writing timing when writing tomographic image data, and a television synchronization circuit 1 that generates read timing when reading tomographic image data from the frame memories 12a to 12n.
4 and a controller 15 that controls the operation of these components.

The subtractor 6 serves as means for performing calculation between the time-series tomographic images obtained by the DSC 5 to generate differential image data thereof, and the television synchronizing circuit 14 described above.
The subtraction is performed between the two tomographic image data read at the read timing from, and the standard logic is used.

The D / A converter 7 converts the difference image data output from the subtractor 6 into an analog signal. Further, the television monitor 8 receives the video signal from the D / A converter 7 and displays it as an image. The D / A converter 7 and the television monitor 8 constitute an image display means.

Here, in the present invention, the above-mentioned DSC5
A region of interest setting device 9 is connected to a controller 15 inside thereof, and an address comparator 10 is provided in a stage preceding the subtractor 6. The region-of-interest setter 9 serves as a means for setting a region of interest (see reference numeral 16 in FIG. 2) consisting of an arbitrary closed-loop figure in the tomographic image displayed on the television monitor 8. It consists of an input device such as a keyboard, displays a mark like a cursor on the TV monitor 8, and moves this mark as appropriate.
A region of interest is set in the displayed image. Alternatively, the area of interest in the display image on the television monitor 8 may be directly traced by the area of interest setting device 9. The shape of the area indicating the region of interest may be any shape, for example, a closed loop figure such as a square. Then, the setting of the region of interest is controlled by the controller 15.

The address comparator 10 serves as processing means for causing the subtracter 6 to perform a difference operation only between image data in the region of interest set by the region of interest setting unit 9, and is provided in the DSC 5. Frame memory 12a-
For each tomographic image stored in 12n, the address of the area set as the region of interest is obtained, and when reading the image data, the address is compared to distinguish between the inside and outside of the region of interest, and the image data in the region of interest is identified. The image data is controlled so that the difference calculation is performed only between them.
The operation of the address comparator 10 is controlled by the controller 15.

Next, the operation of the ultrasonic diagnostic apparatus of the present invention thus constructed will be described. First, the probe 1 shown in FIG. 1 is brought into contact with a position corresponding to the diagnostic region of the subject,
Ultrasound is transmitted to the diagnostic site. At this time, the probe 1
The ultrasonic wave transmitted from the ultrasonic wave is formed into a thin beam at the diagnostic site by the wave-wave phasing circuit in the wave-transmitting circuit 2. The reflected echo reflected by the transmitted beam hitting the diagnostic region is received by the probe 1, and the received beam is formed by the receiving phaser in the receiving circuit 3.
Then, the ultrasonic wave transmission / reception direction is sequentially changed from the probe 1 at a predetermined cycle, and the transmission / reception of ultrasonic waves is repeated to scan the diagnostic region.

The reception beam output from the reception circuit 3 is subjected to required signal processing by the video signal processing circuit 4 and then transmitted to the DSC 5 as a reflected echo signal to be A / D-converted.
It is input to the converter 11 and converted into a digital signal. The DSC 5 has a plurality of line memories (not shown), and writing and reading are performed by switching under the control of the controller 15 each time the ultrasonic wave transmission / reception direction changes, and digital signals are sequentially input for each reception beam. The reflected echo signal of is sent to the frame memories 12a to 12n. The reflected echo signals input to the frame memories 12a to 12n are transmitted to the frame memory 12a serving as the first image storage area by the control signal of the controller 15 so that the transmission / reception directions of the ultrasonic beams are associated with each other. Is written as a tomographic image of, and a first image is formed.

When the ultrasonic scanning of one tomographic image is completed in this way, the probe 1 returns the transmitting / receiving direction to the initial direction again by the control of the transmitting circuit 2 and the receiving circuit 3, and the ultrasonic wave is transmitted. And the transmission / reception direction is updated, and scanning is performed. The reflected echo signals collected this time are also A / D converted in the same manner as above, and sent to the frame memories 12a to 12n in the DSC 5. In this way, the reflected echo signal acquired by this scanning is the controller 1
By the control of 5, the second image is formed by being written as one tomographic image in the frame memory 12b as the second image storage area.

After that, the probe 1 and the DSC 5 continue tomographic scanning to capture the next third tomographic image, and the above operation is repeated to obtain the fourth image,
... The nth image is sequentially formed, and these are formed in the frame memory 1
The images are sequentially stored in the corresponding image storage areas 2a to 12n. Then, the tomographic image data is sequentially read from the frame memories 12a to 12n, passes through the address comparator 10 and the subtractor 6 as they are, is converted into an analog signal by the D / A converter 7, and is sent to the television monitor 8. To be done. As a result, the tomographic images of the diagnosis region are sequentially displayed on the television monitor 8.

The operator sets a region of interest in the tomographic image being displayed on the television monitor 8 by using the region of interest setting device 9 with respect to the motion site to be noticed. For example, as shown in FIG. 2, the first image I ₁ displayed on the screen of the television monitor 8 is displayed.
A region of interest 16 having a square shape is set so as to surround the movement region of the. By setting the region of interest 16, the controller 15 shown in FIG. 1 instructs the address comparator 10 to execute the frame memory 1 corresponding to the image set as described above.
2a, 12b, ... Addresses on the X and Y axes are output.

This state will be described in more detail with reference to FIG. 3 is an enlarged view of the region of interest 16 shown in FIG. 2. Since the region of interest 16 is set to be a square here, the controller 15 first sets the origin (X ₀ ,
Y ₀ ) address is obtained. Next, the length of one side of the region of interest 16 composed of the above-mentioned square is obtained. Next, from the length of this one side and the address of the origin (X ₀ , Y ₀ ), the other points (X ₁ , Y ₀ ), (X ₀ , Y ₁ ), (X ₁ , Y ₁ ) Calculate the address. And these four points (X ₀ , Y ₀ ),
The addresses (X ₁ , Y ₀ ), (X ₀ , Y ₁ ) and (X ₁ , Y ₁ ) are sent to the address comparator 10.

Next, under the control of the controller 15, the clock signal generated from the television synchronizing circuit 14 is used.
For example, the first image and the second image are read from the frame memories 12a and 12b, respectively, with their pixels being associated with each other.
At this time, the read addresses of the frame memories 12a and 12b are also output to the address comparator 10. As a result, the address comparator 10 causes the tomographic image of the subtraction side,
For example, the pixel (X ₀ ,
Y ₀ ), (X ₁ , Y ₀ ), (X ₀ , Y ₁ ), except for the image data in the area surrounded by (X ₁ , Y ₁ ), all the data are set to zero and the subsequent subtractor The image data is controlled so that the image data is output to S6. On the other hand, the tomographic image of the subtracted side, for example, the first
For the image, the address comparator 10 controls the image data so that the image data is directly output to the subtractor 6 as in the case of the normal difference processing.

With the image data thus controlled, the read data of the first image and the second image are input to the subtractor 6. Then, the subtractor 6 is
The difference data between the first image and the second image is output by subtracting each pixel data input corresponding to each other, and as described above, the pixel (X ₀ , Y ₀ ), (X ₁ , Y ₀ ), (X ₀ , Y ₁ ),
Since all the data except the image data in the area surrounded by (X ₁ , Y ₁ ) is zero, the image data in the area surrounded by the above four pixels, that is, in the region of interest 16 is displayed. The difference calculation is performed only between. Then, the difference data of each pixel output from the subtractor 6 is sequentially processed by the D / A converter 7
Is sent to the television monitor 8 via. As a result, a difference image between the first image and the second image is displayed on the television monitor 8.

As a result of the difference calculation as described above, as shown in FIG. 5, only the region of interest 16 set in the first image I ₁ has the difference between the first image and the second image. The image is displayed as the image Is, and the surrounding area is displayed as the original tomographic image. At this time, if the tissue in the region of interest 16 moves during the time elapsed while the first image and the second image are captured, the moved tissue portion is between the first image and the second image. A difference occurs in the image data, the image data is the same between the two images for the stationary tissue portion, the difference data is zero, only the moving tissue is displayed as an image, and the stationary tissue portion is not displayed. That is, what is displayed as a difference image on the television monitor 8 is only the portion that has moved from the time when the first image was captured to the time when the second image was captured. Therefore, by this operation, the difference image Is is obtained only in the region of interest 16 set by the operator as shown in FIG. From this, as shown in FIG. 5, the tomographic image around the region of interest 16 is used as a mask image, and the moving region within the region of interest 16 is displayed as a difference image. Will be easier to observe.

In FIG. 1, both the tomographic image data used for the difference calculation are input to the address comparator 10, but not limited to this, only one tomographic image data is input to the address comparator 10. Entered into and set the region of interest 16
The other tomographic image data is input to the subtractor 6 by bypassing the address comparator 10 while the other tomographic image data is output to the subtractor 6, and subtraction is performed between pixels having addresses corresponding to each other. You may go and output. In addition, the region of interest 16 is set by first performing normal real-time tomographic image display, and setting the region so that the movement region of interest can also include the most expanded range.
Then, ultrasonic scanning for displaying the difference image may be performed.

Regarding the frame rate of the display on the television monitor 8, it is necessary to consider the motion velocity of the motion tissue. Then, in order to obtain a high frame rate tomographic image in order to obtain a difference image of moving tissue faster than the standard frame rate of the image on the television monitor 8, as an ultrasonic transmission / reception technique, for example, the specification of Japanese Patent No. 1095377 (Japanese Patent Publication No. 56-
It is advisable to use the technique described in Japanese Patent No. 20017) together.

FIG. 4 is a block diagram showing a second embodiment of the present invention. This embodiment is different from the embodiment of FIG. 1 in that the frame memory 17a to the output side of the subtracter 6 stores the generated difference image data of the region of interest 16.
17n is provided, and the frame memories 17a-1
On the output side of 7n, an image in the region of interest 16 is obtained from the differential image data of the region of interest 16 output from the frame memories 17a to 17n and the tomographic image data used to generate the differential image data of the region of interest 16. An adder 18 is provided as means for adding the tomographic image data excluding the data. The frame memories 17a to 17n and the adder 18 are controlled by the added controller 19.

The operation of this second embodiment is as follows. First, setting the region of interest 16 as shown in FIGS. 2 and 3 is performed in the same manner as in the above-described first embodiment. Next, under the control of the controller 15, for example, the first image and the second image are read from the frame memories 12a and 12b, respectively, with their pixels corresponding to each other, and output to the next address comparator 10. At this time, the address comparator 10
Is set to zero, except for the tomographic image of the one to be subtracted, for example, the image data in the designated region of interest 16 of the second image, and the tomographic image of the one to be subtracted, for example the first tomographic image.
With respect to the image as well, all the data other than the image data in the designated region of interest 16 is set to zero and output to the subsequent subtractor 6. Then, the subtractor 6 performs a subtraction for each data of corresponding pixels between the data in the ROI 16 of the first image and the data in the ROI 16 of the second image,
The difference image data only within the region of interest 16 is output.
As a result, only the difference image data of the region of interest 16 that is sequentially generated is stored in the next frame memories 17a to 17n.

Next, the frame memories 17a-17n
The difference image data stored in is read out at the cycle of the television synchronizing circuit 14 and input to the adder 18 in the next stage. At this time, the tomographic image data stored in the frame memories 12a to 12n in the DSC 5 are also read in the cycle of the television synchronizing circuit 14 and sent to the address comparator 10 in the next stage. In the address comparator 10, the image data in the region of interest 16 designated in the first image, the second image, etc. is always set to zero and is sent to the adder 18. Accordingly, the adder 18 adds the difference image data in the region of interest 16 from the frame memories 17a to 17n and the tomographic image data outside the region of interest 16 from the address comparator 10,
This combined data is output to the television monitor 8 via the D / A converter 7. As a result, as shown in FIG. 5, the difference image Is in the region of interest 16 with the tomographic image (I ₁ ) as the back.
Is displayed as a single image.

In the case of the second embodiment, the data of each difference image generated by the subtracter 6 is stored in the frame memories 17a-1.
It can be stored in 7n and used at any time.
Further, since only the differential image data is stored in the frame memories 17a to 17n, the storage capacity thereof may be small, and the frame memories 17a to 17n can be miniaturized.

The present invention is not limited to the above-mentioned embodiment, and it goes without saying that various modifications can be made. For example, a differential image of the entire image is first generated from the first image and the second image of the tomographic image, and only the region of interest of this differential image is put in a place excluding the region of interest of the original tomographic image and combined. You can

[0033]

Since the present invention is constructed as described above,
Image display means (8) by the region of interest setting means (9)
A region of interest 16 composed of a closed loop arbitrary figure is set in the tomographic image displayed on the screen, and the region of interest 1 set by the region of interest setting means (9) by the processing means (10).
The difference calculation can be performed by the difference image data generating means (6) only between the image data within 6. As a result, the difference image Is can be displayed only in the region of interest 16 set in the tomographic image of the diagnosis region of the subject, and the motion state can be visualized with the tomographic image as the back. Therefore, a stationary portion such as a contour is also displayed on the back tomographic image, and it becomes easy to observe the relation of the movement of the moving portion in the entire diagnosis portion, and the diagnosis is accurate and easy.

In the second embodiment shown in FIG. 4, the storage means (17a to 17n) provided on the output side of the differential image data generation means (6) sequentially stores the differential image data in the region of interest 16. Since it can be stored, the difference image and the original tomographic image can be arbitrarily used at any time.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an ultrasonic diagnostic apparatus according to the present invention,

FIG. 2 is an explanatory diagram showing a state in which a region of interest is set in a displayed tomographic image,

FIG. 3 is an explanatory view showing the region of interest in an enlarged manner;

FIG. 4 is a block diagram showing a second embodiment of the present invention,

FIG. 5 is an explanatory diagram showing images displayed by the first embodiment and the second embodiment,

FIG. 6 is an explanatory diagram for explaining a display operation of a difference image in a conventional example.

[Explanation of symbols]

1 ... Probe, 2 ... Transmitting circuit, 3 ... Receiving circuit, 4 ...
Video signal processing circuit, 5 ... DSC, 6 ... Subtractor,
7 ... D / A converter, 8 ... TV monitor, 9 ... ROI setting device, 10 ... Address comparator, 12a-12n,
17a to 17n ... Frame memory, 16 ... Region of interest,
18 ... Adder, Is ... Difference image.

Claims (2)

[Claims] 1. An ultrasonic wave transmitting / receiving means for transmitting and receiving ultrasonic waves to and from a subject, and tomographic image data in the subject including a moving tissue are repeated at a predetermined cycle using reflected echo signals from the ultrasonic wave transmitting / receiving means. To obtain the difference image data, the means to perform a difference operation between the time-series images obtained by the tomographic scanning means to generate the difference image data, and the difference image data from the difference image data generating means. In an ultrasonic diagnostic apparatus having an image display means, a region of interest setting means for setting a region of interest formed of a closed loop arbitrary figure in the tomographic image displayed on the image display means is provided,
An ultrasonic diagnostic apparatus comprising a processing means for causing the difference image data generation means to perform a difference calculation only between image data within the interest area set by the interest area setting means. 2. An output side of the differential image data generating means is provided with a storage means for storing the generated differential image data of the ROI, and an output side of the storage means is an ROI from the storage means. And a tomographic image data obtained by removing the image data in the region of interest from the tomographic image data used to generate the differential image data of the region of interest are displayed. The ultrasonic diagnostic apparatus according to claim 1, wherein: