JPH05184577A - Ultrasonic diagnostic device - Google Patents

Abstract

PURPOSE:To extract a kinetic component by a difference operation with regard to the part whose motion is slow, as well, and also, to display a smooth image being free from flickering without lowering a frame rate of a difference image. CONSTITUTION:A subtracter 4 provided in a post-stage of a DSC 3 executes a difference by each designated tomographic image at an interval of (m) pieces (m denotes an integer of >=2) as a time series with regard to image data fetched successively from the DSC 3 under the control of a controller 7, and also, generates image data by a difference in a period of (k) folds (1<=k<m) of a prescribed period of tomographic image data. In such a way, an interval for taking a difference between two tomographic images is set to two frames or above, and a generation period of difference image data sent out to an image indicator 6 side can be made smaller than the difference interval.

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 capable of extracting a motion component of a diagnostic region of a subject, for example, a moving tissue such as a blood vessel or a heart, using ultrasonic waves and displaying it as a difference image. In particular, the present invention relates to an ultrasonic diagnostic apparatus capable of extracting a motion component of a slow-moving part and displaying a smooth image without flicker without lowering the frame rate of a difference image.

[0002]

2. Description of the Related Art A conventional ultrasonic diagnostic apparatus having a function of extracting a difference image is disclosed in Japanese Patent Application Laid-Open No. 62-189054 or Japanese Patent Application Laid-Open No.
As described in JP-A-121058, an ultrasonic wave transmitting / receiving unit (a probe and an ultrasonic wave transmitting / receiving unit) for transmitting and receiving ultrasonic waves to and from a subject and a reflection echo signal from this ultrasonic wave transmitting / receiving unit are used. And a difference image between the tomographic scanning means (digital scan converter) obtained by repeatedly obtaining the tomographic image data in the subject including the moving part at a predetermined cycle and the time series images obtained by the tomographic scanning means. It is provided with means for generating data (difference processor), image display means (television monitor) for displaying the difference image data from this difference image data generation means, and control means for controlling the operation of each of the above-mentioned components. Was made.

In this case, if a moving part in the subject moves during the time elapsed when the image of the previous scan and the image of the current scan are captured in the time series images obtained by the tomographic scanning means, For the moving part, a difference occurs in the image data between the previous image and the current image, and for the stationary part, the image data is the same between both images, the difference data is zero, and only the moving part is displayed as an image. There are the following two ways to display the difference image at this time.

First, in the first image display, as shown in FIG. 6, before and after images which are adjacent to each other from the image storage means in the tomographic scanning means, for example, the first image I ₁ and the second image I ₂ , 2 image I ₂ and third image I ₃ , third image I ₃ and fourth image I ₄ , ...
The (n-1) th image In-1 and the nth image In are sequentially read out, and the difference image data generating means subtracts each of these images to sequentially generate difference image data. Then, the difference image Is ₁ , obtained in this way,
Is _2, Is _3, to display ... to sequentially image display means. The time interval of each differential image displayed at this time is equal to the time interval T of each of the tomographic images I ₁ , I ₂ , ...

[0005] Next, display the second image, as shown in FIG. 7, the image I ₁ are sequentially collected by the tomographic scanning means in the same manner as described above, I _2, I _3, ..., for In, for example, m sheets ( m is an integer of 2 or more) at intervals of the first image I ₁ , the fourth image I ₄ , and the fourth image I ₄ .
Image I ₄ and the seventh image I _7, the seventh image I ₇ 10 image I _10, read by specifying ... like at intervals of, and respectively subtracting the differential image data generating means between the images, discrete Is the difference image data _{1, Is 4, Is 7,} ...
To generate. Then, the difference image data Is ₁ , Is ₄ , Is ₇ , ... Obtained in this way are sequentially displayed on the image display means. The time interval of each difference image displayed at this time is mT.
Becomes

[0006]

However, in such a conventional ultrasonic diagnostic apparatus, the above-mentioned first image display is
For example, it is suitable for extracting and displaying the movement of fast-moving organs such as a heart valve, but for slow-moving organs such as an abdominal blood vessel, it is possible to compare the images before and after adjacent images. There was almost no difference, the movement of the organ could not be extracted, and it was not suitable for displaying the difference image of the slow-moving organ.

On the other hand, in the above-mentioned second image display, two images are skipped every m images for a large number of tomographic images arranged in time series, and subtraction is performed between the images. Since the differential image data is generated, it is possible to extract the motion component of the slow-moving organ and display the differential image as a moving image. However, in this case, as shown in FIG. 7, the difference image data Is ₁ , Is ₄ ,
Since Is ₇ , ... Are only generated intermittently at intervals of m sheets, the frame rate of the difference image is lowered, and the display image may flicker, making it difficult to see the diagnostic image.

Therefore, the present invention addresses such a problem, can extract the motion component of a slow-moving portion, and displays a smooth image without flicker without lowering the frame rate of the difference image. It is an object of the present invention to provide an ultrasonic diagnostic apparatus that can be used.

[0009]

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 differential image data between the time-series images obtained by the tomographic scanning means. In the ultrasonic diagnostic apparatus, the differential image data is provided with an image display unit that displays the differential image data from the differential image data generating unit, and a control unit that controls the operation of each component. The generation means, under the control of the control means, sets the tomographic images designated at time intervals of m (m is an integer of 2 or more) image data sequentially captured from the tomographic scanning means. Min performs, in which shall be generated image data according to the difference in the period of k times the predetermined period of said tomographic image data (1 ≦ k <m).

[0010]

In the ultrasonic diagnostic apparatus configured as described above, the differential image data generating means that operates under the control of the control means performs time-sequential m sheets of image data (m is 2 or more) of the image data sequentially captured from the tomographic scanning means. The difference between the tomographic images designated by the interval is performed, and the image data based on the difference is generated at a cycle of k times (1 ≦ k <m) the predetermined cycle of the tomographic image data. That is, the control means sets the interval for obtaining the difference between the two tomographic images to be 2 frames or more,
The image display means is operated so that the generation cycle of the differential image data sent to the frame is smaller than the differential interval. This makes it possible to extract the motion component of the slow-moving part of the diagnosis part and display a smooth image without flicker without lowering the frame rate of the difference image.

[0011]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. 1 is a block diagram showing a first embodiment of an ultrasonic diagnostic apparatus according to the present invention. This ultrasonic diagnostic apparatus is capable of extracting and displaying a component of the movement of a diagnostic region of a subject, particularly a moving tissue such as a blood vessel or a heart, by using ultrasonic waves. The child 1, the ultrasonic transmission / reception circuit 2, the digital scan converter (hereinafter abbreviated as “DSC”) 3, the subtractor 4, the D / A converter 5, the image display 6, and the controller 7. Be prepared.

The probe 1 mechanically or electronically performs beam scanning to transmit and receive ultrasonic waves to and from the subject 8. Although not shown, it is a source of ultrasonic waves. In addition, a transducer that receives the reflected echo is built in. The ultrasonic wave transmission / reception circuit 2 sends a drive pulse to the probe 1 to generate ultrasonic waves and processes a signal of the received reflection echo. , A wave delaying circuit, a wave receiving amplifier, a wave receiving delay circuit, an adder, and the like, a phasing circuit and a detection circuit are built-in. The probe 1 and the ultrasonic wave transmission / reception circuit 2 constitute an ultrasonic wave transmission / reception means, and the ultrasonic wave is scanned by the probe 1 inside the body of the subject 8 to obtain one slice. I'm supposed to get a statue.

The DSC 3 obtains tomographic image data of the inside of the subject 8 including the moving part in the ultrasonic wave transmission cycle by using the reflected echo signal output from the ultrasonic wave transmitting / receiving circuit 2 and displays the data in order to display this data. The synchronous reading is performed and the controller 7 forms a tomographic scanning means. An A / D converter 9 for converting the reflected echo signal from the ultrasonic transmission / reception circuit 2 into a digital signal and an output from the A / D converter 9 are provided. A buffer memory 10 for repeatedly writing and reading a digital signal to / from a line memory for each scanning line or a plurality of scanning lines of an ultrasonic beam, and sending the image signal to an image memory 11 described later, and an image output from this buffer memory 10. The image memory 11 is capable of storing data for one frame at a time, and includes, for example, a semiconductor memory and an image memory 11 having a plurality of frames of storage areas.

The subtractor 4 serves as means for performing subtraction between the two tomographic images of the image data output from the DSC 3 to generate differential image data thereof, and the subtracter 4 sequentially outputs the image data from the image memory 11. The pixel data is subtracted from the two frames of image data corresponding to each other to output difference data. For example, the positional information of the input two frames of the tomographic image is used as an address, and the difference in luminance at that position is calculated. It is composed of a calculation RAM written so as to be output as difference data. In addition, this subtractor 4
May use a normal adder that adds a negative sign to one of the data and adds.

The D / A converter 5 inputs the difference image data output from the subtractor 4 and converts it into an analog signal. The image display 6 is for inputting the video signal output from the D / A converter 5 and displaying an image, and is composed of, for example, a television monitor. Then, the D / A converter 5 and the image display 6 constitute an image display means. Further, the controller 7 controls the overall operation of each of the above components, and is composed of, for example, a CPU.

Here, in the present invention, the subtractor 4 is used.
Under the control of the controller 7, the difference between the tomographic images designated at intervals of m sheets (m is an integer of 2 or more) of the image data sequentially fetched from the DSC 3 is obtained, and the tomographic image data of a predetermined cycle is obtained. k times (1 ≦ k <m)
It is supposed that the image data is generated by the above difference in the cycle. That is, the controller 7 sets the interval for obtaining the difference between the two tomographic images to 2 frames or more, and operates so that the generation cycle of the difference image data sent to the image display device 6 is smaller than the difference interval. It is like this. In other words, the difference time for obtaining the difference between the two tomographic images is increased to some extent or more, and the display interval of the difference images obtained thereby is made smaller than the difference time.

Next, the operation of the first embodiment thus constructed will be described with reference to FIG. First, the probe 1 is brought into contact with the subject 8 and ultrasonic waves are transmitted toward a diagnostic site (including a motion site) of the subject 8. At this time, the transmitted ultrasonic wave is made to form a thin beam at the diagnostic site by the transmission delay circuit in the ultrasonic wave transmission / reception circuit 2. The reflected echo of the transmitted ultrasonic beam is received by the probe 1 and taken into the ultrasonic transmission / reception circuit 2 via the amplifier, the reception delay circuit, the adder, etc., and the ultrasonic reception beam is formed. Then, from the probe 1, the transmitting and receiving directions of ultrasonic waves are sequentially changed at a predetermined cycle, and the transmitting and receiving waves are repeatedly performed so as to ultrasonically scan the diagnostic region of the subject 8.

Next, the echo signal (analog signal) output from the ultrasonic wave transmitting / receiving circuit 2 is converted into a digital signal by the A / D converter 9 and output to the buffer memory 10. The buffer memory 10 is composed of a plurality of line memories, and writing and reading are alternately switched by the controller 7 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 11. The echo signal input to the image memory 11 is sequentially transmitted to and received from the first image storage area 11 ₁ by the control signal of the controller 7 for each ultrasonic beam, and the first image I shown in FIG. _It is written so as to form one ultrasonic tomographic image that becomes 1.

Next, when the ultrasonic scanning for one image is completed by the control of the ultrasonic wave transmitting / receiving circuit 2, the probe 1 returns the transmitting / receiving direction to the initial direction again, repeats the transmitting / receiving wave, and transmits / receives the wave. Are sequentially changed for each transmission / reception wave and scanning is performed. Therefore, the echo signal is also A / D converted by the A / D converter 9 and output to the image memory 11 via the buffer memory 10 as described above. The image memory 11 is controlled by the controller 7 so as to write the echo signal captured by the current scanning into the second image storage area 11 ₂ . Then, when the writing of data to the _second image storage area 11 ₂ is completed with the progress of the ultrasonic scanning, the second image I ₂ shown in FIG. ₂ is formed. Thereafter, similarly, the third image I ₃ , the fourth image I ₄ , the fifth image I ₅ , ... Are sequentially formed and written in the corresponding image storage areas.

Then, under the control of the controller 7, the two image data designated at intervals of m sheets (m is an integer of 2 or more) are read out from the image memory 11 by shifting one frame at a time, and the data is read between them. The subtractor 4 calculates the difference. For example, the intervals are three, and the first image I ₁ and the fourth image I ₄ , the second image I ₂ , the fifth image I ₅ , and the third image I _{3 are} separated.
, And the sixth image I ₆ , ..., Two image data are sequentially read out, and these are input to the subtracter 4 to sequentially perform difference calculation between corresponding images. As a result, the first image I
_{From 1} and the fourth image I ₄ , the first difference image Is ₁ becomes the second image I
₂ and a second difference image Is ₂ from the fifth image I ₅ Prefecture, third image I
The third difference image Is ₃ is generated from ₃ and the sixth image I _6, and the difference images are sequentially generated in the same manner.

Thereafter, the difference image data output from the subtractor 4 is input to the D / A converter 5, converted into an analog signal, and sequentially sent to the image display 6. And
The image display 6 subjects the input video signal to luminance modulation and displays it as an image. Image displayed at this time is the difference between images of m sheets interval as described above is taken, 1 difference image Is ₁ shifted by frame, Is _2, Is _3, has ... a.

FIG. 3 is a block diagram showing a second embodiment of the present invention. In this embodiment, the storage capacity of the image memory 11 ′ provided inside the DSC 3 is set to the amount capable of storing the number of frames corresponding to one cycle of the movement of the target organ, and in the subsequent stage of the subtractor 4. A second image memory 12 for storing difference image data generated from a plurality of tomographic image data corresponding to one cycle of the movement of the target organ is provided. In the first embodiment shown in FIG. 1, the DSC3
The image memory 11 in the inside has a plurality of frames (for example, 3 to 10).
Although it has a storage capacity of only about a frame), in the present embodiment, the image memory 11 'has a storage capacity of n frames (for example, 30 frames). In addition, the second image memory 12 also has n frames (for example, 30 frames).
It has a storage capacity of (frame).

In the case of the second embodiment, the tomographic image data obtained by the ultrasonic scanning by the DSC 3 is sequentially input to the image memory 11 'under the control of the controller 7, and the first image storage area 11 is also provided. The first image I ₁ , the second image I ₂ , ..., The nth image are stored in the _1st to nth image storage areas 11n.
It is sequentially written like an image In. And the first
The image memory 1 from the image I ₁ to the nth image In
After being written in 1 ', as shown in FIG. 2, the tomographic image data is designated and read at m-sheet intervals, and the subtracter 4 calculates the difference between these images and sequentially outputs the difference image data. .. The difference image data obtained in this way is sequentially stored as the first difference image Is ₁ , the second difference image Is ₂ , ..., And the nth difference image Isn in the respective image storage areas 12 _{1 to} 12n of the second image memory 12. Written in. Then, the difference images Is _{1 to} Isn are sequentially read out from the second image memory 12, converted by the D / A converter 5 into analog data, and displayed on the image display device 6.
The difference image is displayed on. In this case, since the tomographic images of the number of frames corresponding to one cycle required for the observation of the diagnostic region of the subject 8 are captured in advance and all of them are stored, the difference image described above is always or repeatedly obtained. Can be displayed. Also, when displaying this difference image,
The calculation process for obtaining the difference image does not need to be synchronized with the refresh operation of the image display 6, and the difference image process can be performed according to a unique time chart.

FIG. 4 is a block diagram showing a third embodiment of the present invention. In this embodiment, the second image memory 12 is used.
A color encoder 13 as a means for adding hue information to the difference image data read from the color encoder 13 is provided in the subsequent stage, and a DS encoder is provided in the subsequent stage of the color encoder 13.
An adder 14 is provided as means for superimposing the black and white tomographic image data output from C3 and the difference image data to which the hue information is added by the color encoder 13. The image display 6'in this embodiment is capable of color display. In this case, with respect to the difference image data read from the second image memory 12, it is possible to add hue information to display the moving part in color and to display the image of the moving part displayed in color as a black and white tomographic image. Can be combined and displayed simultaneously.

Regarding the display operation in the case of the third embodiment,
This will be described with reference to FIG. Image memory 1 in DSC3
In 1 ', the tomographic image data includes the first image I ₁ to the n-th image I.
n are sequentially stored, and the differential image data is sequentially stored in the second image memory 12 as a first differential image Is ₁ , a second differential image Is ₂ , a third differential image Is ₃ , .... In this state, a read signal is first sent from the controller 7 shown in FIG. 4 to the image memory 11 'and the second image memory 12. Then, the first image I ₁ is read from the image memory 11 ′ and the first difference image Is ₁ is read from the second image memory 12. Then, the read data of the first difference image Is ₁ is input to the next color encoder 13, where R (red), G (green),
Any one of the B (blue) hue information or the hue information obtained by combining the hue information is added to the color first difference image I.
It becomes sc ₁ . Next, the first difference image Isc _{1 of} this color and the read first image I ₁ are respectively added by the adder 14
Is input to each pixel address and added for each corresponding pixel address to generate a composite image of a black and white tomographic image and a color difference image.
Thereafter, the data of the composite image is input to the D / A converter 5 of FIG. 4 to be converted into a video signal, which is displayed on the color image display 6 '.

After that, by sequentially repeating the above-described operation, it is possible to display the difference image of the moving part such as the valve of the heart in color in the black and white tomographic image, and to clearly display the moving state. it can. Further, it becomes possible to observe the diagnosis part while grasping the positional relationship of the motion parts in the surrounding stationary part. In addition, when displaying only a black and white tomographic image, or when displaying only a color difference image,
The read signal of the image data from the controller 7 may be sent to only the image memory 11 'or only the second image memory 12.

In the above description, in FIG. 2, the interval between the tomographic images I ₁ , I ₂ , I ₃ , ... For calculating the difference is 3.
And the difference images Is ₁ , Is ₂ , Is ₃ ,
.. are displayed while being shifted by one frame, but the present invention is not limited to this, and it is assumed that the intervals of the tomographic images for taking the difference may be any number of two or more, and the display of the difference image does not exceed the difference interval. Alternatively, the display may be shifted by two frames or more.

[0028]

Since the present invention is constructed as described above,
The differential image data generation means (4) operating under the control of the control means (7) designates image data sequentially captured from the tomographic scanning means (3) in time series at intervals of m (m is an integer of 2 or more) intervals. It is possible to perform a difference between the tomographic images thus obtained and to generate image data based on the difference at a cycle that is k times (1 ≦ k <m) the predetermined cycle of the tomographic image data. That is, by the control means (7), the interval for obtaining the difference between the two tomographic images is set to 2 frames or more, and the generation cycle of the differential image data sent to the image display means (6) is smaller than the difference interval. can do. This makes it possible to extract the motion component of the slow-moving part of the diagnosis part and display a smooth image without flicker without lowering the frame rate of the difference image. Therefore, the diagnostic image can be made easy to see.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram showing an operation of generating a difference image and displaying the image in the first embodiment,

FIG. 3 is a block diagram showing a second embodiment of the present invention,

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

FIG. 5 is an explanatory diagram showing an operation of generating a difference image and displaying the image in the third embodiment.

FIG. 6 is an explanatory diagram showing an example of an image display operation in a conventional ultrasonic diagnostic apparatus,

FIG. 7 is an explanatory diagram showing another example of the image display operation in the conventional ultrasonic diagnostic apparatus.

[Explanation of symbols]

1 ... Probe, 2 ... Ultrasonic wave transmitting / receiving circuit, 3 ... DSC,
4 ... Subtractor, 5 ... D / A converter, 6 ... Image display, 7 ... Controller, 8 ... Subject, 9 ... A / D
Converter, 10 ... Buffer memory, 11, 11 '... Image memory, 12 ... Second image memory, 13 ... Color encoder, 14 ... Adder.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinji Kishimoto 2-1, Shinjuyo, Kashiwa City, Chiba Prefecture Inside the Nititsu Medical Research Institute

Claims (1)

[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. Obtained by the tomographic scanning means, means for performing calculation between the time-series images obtained by the tomographic scanning means to generate their difference image data, and an image displaying the difference image data from the difference image data generating means. In the ultrasonic diagnostic apparatus comprising a display means and a control means for controlling the operation of each of the above-mentioned components, the difference image data generation means, by the control of the control means, the image data sequentially captured from the tomographic scanning means. Differences are made between the tomographic images designated at time-series intervals of m sheets (m is an integer of 2 or more), and k times the predetermined period of the tomographic image data (1
An ultrasonic diagnostic apparatus characterized in that it generates image data based on the difference in a cycle of ≦ k <m).