JPH0787397A - X-ray fluoroscopic diagnostic device - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a high-quality image with proper image adjustment without frame delay even when the X-ray irradiation field is moved while performing image adjustment. Structure: X-rays emitted from an X-ray tube 21 and transmitted through a subject 23 are converted into image data, and the converted image data is temporarily stored in a frame memory 34 for each frame. The speed detectors 31a and 31b detect the moving direction and moving speed of the X-ray irradiation field with respect to the subject 23. Speed detector 31
The prediction calculation unit 35 estimates the region of interest of the next frame on the image data of the current frame stored in the frame memory 34 from the detection values of a and 31b and the region of interest designated by the region of interest designating unit 37. The adjustment coefficient calculator 36 calculates an image adjustment coefficient from the image data of the frame memory 34 corresponding to the estimated region of interest. The A / D converter 32 performs the required image adjustment according to the calculated image adjustment coefficient.
And an image processing unit 33 that applies the image data converted in.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray fluoroscopic diagnostic apparatus for diagnosing a patient based on an X-ray image of a subject, and more particularly to automatically adjusting the brightness and contrast of the X-ray image. The present invention relates to an X-ray fluoroscopic diagnosis apparatus having an image adjustment function.

[0002]

2. Description of the Related Art Conventionally, in the diagnosis and treatment of cardiovascular diseases,
Angiography is performed by administering to a patient a contrast agent composed of an iodine liquid that is difficult to transmit X-rays. In this type of examination, a digital fluorography device capable of image recording (hereinafter referred to as DF
X-ray image diagnostic apparatus in which a device) is combined with an X-ray diagnostic apparatus.

The DF device is a device for converting an X-ray image obtained by irradiating pulsed X-rays in time series into image data composed of digital signals and performing various image processing, and it is a low-contrast imaging. There are advantages such as being able to clearly display blood vessels and making quantitative diagnosis.

In recent years, stepping see-through / photographing has been performed as one of the methods using the DF device. This method is a method of performing fluoroscopy / imaging while moving the X-ray irradiation field by moving the top plate or the X-ray tube-X-ray detection system while irradiating X-rays.

On the other hand, one of the image processing functions performed by the DF device is automatic adjustment of image brightness and contrast. This function temporarily inputs image data for one frame into a frame memory and automatically adjusts brightness and contrast based on the image data in the region of interest designated by an operator or the like.

An example of an X-ray image diagnostic apparatus using such a DF apparatus is shown in FIG. The X-rays emitted from the X-ray tube 1 pass through the subject 3 supported by the top plate 2 and enter the image intensifier (hereinafter referred to as II) 4, and are converted into optical image data. To be converted. In the figure, reference numeral 1a is X
Reference numeral 5 denotes an X-ray controller, respectively, and a line diaphragm.

I. I. The output data 4 is then converted into a TV video signal by the image pickup device 6 such as an image pickup tube or a solid-state image pickup device, and further converted into digital image data by the A / D converter 7. This digital image data is output to the system of the frame memory 8 and the adjustment coefficient calculation unit 9 for calculating the image adjustment coefficient, and the image processing unit 10 that actually performs image processing.

Of these, in the former system, after the output data of the A / D converter 7 is temporarily stored in the frame memory 8, the ROI information output from the ROI specifying unit 14 is designated by the operator or the like. At the same time, it is read by the adjustment coefficient calculator 9. The adjustment coefficient calculation unit 9 calculates, for example, the brightness and contrast adjustment coefficient of the image based on the image data corresponding to the designated region of interest, and outputs the adjustment coefficient to the image processing unit 10.

On the other hand, the image processing section 10 has another frame memory 10a, an image processing circuit 10b, and an image adjusting circuit 10c, and the output data of the A / D converter 7 is temporarily stored in the frame memory 10a. Be remembered. The image adjustment circuit 10c reads the image data waiting in the frame memory 10a via the image processing circuit 10b, and uses the adjustment coefficient supplied from the adjustment coefficient calculation unit 9 to adjust the brightness of the read image data. And performing contrast adjustment processing. The image data after this image adjustment processing is
After being converted into a TV video signal by the D / A converter 11,
It is sent to the display 12.

As a result, the image adjustment circuit 10c uses the adjustment coefficient obtained from the image data in the region of interest of the N-1th frame image data, for example, to use the image data of the N-1th frame, that is, the self-adjustment coefficient. Image adjustment processing is automatically performed on the image. The image data thus image-processed is displayed on the display 12 every frame as a fluoroscopic image by X-ray.

Further, in FIG. 3, it is assumed that the frame memory 10a is not provided. In this case, the data flow is the same, but the image adjustment circuit 10c uses an adjustment coefficient calculated based on the image data in the region of interest of the N−1th frame to optimize the region. , Nth frame is automatically adjusted.

[0012]

However, in the above-mentioned X-ray image diagnostic apparatus, an image on which the adjustment coefficient is determined by using the frame memory 8 and the adjustment coefficient operation unit 9 and which is the basis of the determination, That is, in order to perform the adjustment process on the self-image, another frame memory 1 is provided in the image processing unit 10.
Since 0a is provided, the fluoroscopic image displayed on the display 12 is delayed by one frame from the fluoroscopic image collected at that time. Therefore, for example, when a catheter is inserted into a body and operated while seeing the X-ray fluoroscopic image, the shift between the actual operation and the displayed fluoroscopic image often gives the operator a feeling of strangeness in operation.

In order to solve the above-mentioned problem, the frame memory 10a is eliminated, and the frame memory 8 and the adjustment coefficient calculating unit 9 are used to generate the (N-1) th region based on the image data in the (N-1) th region of interest. An adjustment coefficient for optimizing the image is calculated, and the actual image adjustment is performed on the Nth image.
However, in this method, in particular the X-ray tube 1 and the I.V. I. Four
When the X-ray irradiation field is moved in the direction along the body axis of the subject 3 by the drive signal s from the drive device 13 or the tabletop 2, the ROIs of the N-1th and Nth frames If there is a large change in brightness and contrast between the images inside, inappropriate brightness and contrast adjustment will result.

Although the deviation between the displayed perspective image and the actual operation and the improper image adjustment are eliminated unless the image adjustment processing is performed, the fluoroscopic image in which the brightness / contrast is not adjusted becomes a visible image. There is a problem that diagnosis is hindered.

The present invention has been made in view of the above-mentioned circumstances, and is a case where the X-ray irradiation field is moved while performing image adjustment processing such as brightness and contrast adjustment in the region of interest on the screen. Even so, it is an object of the present invention to provide an X-ray fluoroscopic diagnosis apparatus capable of performing appropriate image adjustment processing without frame delay.

[0016]

In order to solve the above-mentioned object, an X-ray fluoroscopic diagnosis apparatus according to claim 1 is an X-ray irradiation means for irradiating an X-ray toward a diagnosis site of a subject, and An X-ray fluoroscopic diagnostic apparatus comprising: a conversion unit for converting X-rays transmitted through an object into image data, subjecting the image data to predetermined image processing, and displaying the image data on a display as a fluoroscopic image. A storage unit for temporarily storing the image data converted by the conversion unit for each frame; a detection unit for detecting a moving direction and a moving speed of the X-ray irradiation field with respect to the subject; and an interest in the image data. Designating means for designating a region, region estimating means for estimating a region to be a region of interest in the next frame based on the detection value of the detecting means and the region of interest designated by the designating means, Adjustment coefficient calculation means for calculating an image adjustment coefficient based on the image data of the storage means corresponding to the region of interest estimated by the area estimation means, and a required amount corresponding to the image adjustment coefficient calculated by the adjustment coefficient calculation means. Image adjusting means for performing the image adjustment of (1) on the image data converted by the converting means.

[0017]

The X-rays emitted from the X-ray exposure means are converted into image data after passing through the subject. The image data (for example, the image data of the (N-1) th frame) is temporarily stored in the storage unit and also supplied to the image adjustment unit.

In parallel with this data supply, the area estimating means is based on the moving direction and moving speed of the X-ray irradiation field output from the detecting means with respect to the subject and the ROI information output from the designating means. , The next frame (for example, Nth frame) on the image data of the current frame (for example, N-1th frame) stored in the storage means.
The area to be the area of interest is estimated at. Based on the image data of the storage means corresponding to this estimated region of interest,
The adjustment coefficient calculation means calculates an image adjustment coefficient for performing a desired image adjustment process on the image data of the next frame (for example, the Nth frame).

As a result, the image adjustment means performs the required image adjustment based on the given image adjustment coefficient (coefficient for the image data of the Nth frame estimated from the image data of the N-1th frame). It can be applied to the image data (N-th frame image data) input from the conversion means.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an X-ray fluoroscopic diagnosis apparatus according to the present invention will be described below with reference to FIGS.

The X-ray fluoroscopic diagnostic apparatus shown in FIG. 1 includes an X-ray tube 21 for irradiating X-rays, an X-ray controller 22 for controlling the X-ray output from the X-ray tube 21, and a subject 23. The top plate 24 that supports the X-ray fluoroscopic image transmitted through the subject 23 is converted into an optical image I. I. 25 and this I.S. I. An image pickup device 26 such as an image pickup tube and a solid-state image pickup element for converting an output image of the image pickup device 25 into a TV video signal is provided. On the X-ray exposure side of the X-ray tube 21, the I. I. A variable diaphragm device 21a for narrowing down the irradiation X-rays is attached so that the irradiation area to 25 coincides with the X-ray irradiation surface (that is, the irradiation field).

Of these, the X-ray tube 21 and the I.D. I. 25 are attached to the support 27 so as to face each other,
A drive device 28 drives the support body 27. As a result, the X-ray tube 21 and the I.D. I. 25 is integrally movable in the longitudinal direction of the top plate 24 (that is, the body axis direction of the patient as the subject 23) and the lateral direction orthogonal thereto. The drive device 28 is operated by a drive signal s output by the control device based on a movement signal instructed by the operator from the console.

The top plate 24 is slidably attached to the upper surface of the bed 29 along the longitudinal direction of the bed 29, and slides in the longitudinal direction in response to a drive signal s from the drive unit 30. ing. A drive signal s is also given to the drive unit 30 from a control unit (not shown).

Thus, the support 27 (that is, the X-ray tube 21
And I. I. 25) and at least one of the top plate 24 is moved along the longitudinal direction, so that the X-ray irradiation field can be moved at least in the longitudinal direction and the lateral direction of the top plate 24.

In order to grasp the movement states of the support 27 and the top plate 24, in this embodiment, speed detectors 31a and 31b, which are, for example, rotary encoders, are attached. As a result, the speed detectors 31a and 31b output electric signals according to the moving direction and moving speed of the support 27 and the top plate 24.

On the other hand, an A / D converter 32 is connected to the image pickup device 26, and the conversion output of the A / D converter 32 is 2
There is a branch in the system. Of these, one is an image processing unit 33 that automatically adjusts brightness and contrast as one of image processing for a perspective image, and the other calculates an adjustment coefficient for adjusting the brightness and contrast. It is a system.

The system for calculating the adjustment coefficient includes a frame memory 34, a prediction calculation section 35, and an adjustment coefficient calculation section 36.
Are arranged. The frame memory 34 has a storage area corresponding to input image data for one frame, and
The digital image data converted by the D converter 32 is stored for each frame.

Further, the prediction calculation unit 35 is connected to a region-of-interest designating unit 37 for designating a required region in the frame image data as a region of interest based on designation information from an operator or the like. The prediction calculation unit 35 reads out the image data stored in the preceding frame memory 34 at regular timings, and also reads the specified region of interest and the detection signals of the speed detectors 31a and 31b described above. And
When the X-ray irradiation field is moved, the area to be the region of interest of the next frame is estimated on the image data stored in the frame memory 34.

The image data of the estimated region of interest is
It is sent to the adjustment coefficient calculation unit 36 in the subsequent stage, and the adjustment coefficient for optimizing the brightness and contrast adjustment is calculated.
This adjustment coefficient is sent to the image processing unit 33.

In the image processing section 33, the image data converted by the A / D converter 32 is read into the image adjusting circuit 33b via the image processing circuit 33a. The image adjustment circuit 33b is
The brightness and contrast adjustment processing for each pixel value is performed by, for example, multiplying each image data by the adjustment coefficient given from the adjustment coefficient calculation unit 36 at that time.

The image data after this image adjustment is D /
It is sent to the display 39 via the A converter 38. As a result, the image data is converted into a TV video signal by the D / A converter 38 and displayed on the display 39 as a perspective image.

Here, the X-ray tube 21 and the X-ray control device 22 constitute the X-ray exposure means of the present invention, and the I.D. I. 25, the image pickup unit 26, and the A / D converter 32 constitute the conversion means of the present invention. Further, the frame memory 34 forms the storage means of the present invention, the prediction calculation section 35 forms the area estimation means, and the adjustment coefficient calculation section 36 forms the adjustment coefficient calculation means. Further, the image processing device 33 forms the image adjusting means of the present invention, the speed detectors 31a and 31b form the detecting means of the present invention, and the ROI designating section 37 forms the designating means of the present invention.

Next, the overall operation will be described centering on the prediction / calculation processing of the prediction calculation unit 35.

Pulsed X-rays are radiated from the X-ray tube 21 at fixed timings, and the X-rays related to this radiation are emitted from the subject 2
3, transmitted through the top plate 24, and I.D. I. It is incident on 25. I.
I. In 25, as described above, the projected image of the incident X-ray is converted into an optical image for each perspective frame and output to the image pickup device 26. In the imaging device 26, the incident optical image is converted into image data of an electric signal corresponding to this image, and this image data is converted into A
The digital value is converted by the / D converter 32. The converted image data is input to the image processing unit 33 and also to the frame memory 34 to be stored.
The image data for one frame stored in the frame memory 34 is read by the prediction calculation unit 35 at an appropriate timing. In addition, a required area on the frame image is designated as a region of interest from the region of interest designating unit 37, and the region of interest is input to the prediction calculation unit 35.

Now, N-2, N-1, N, N + 1, ...
Fluoroscopy proceeds in the order of frames (N is an integer), for example, N-1
If the image data of the th frame is displayed, it becomes, for example, as shown by the solid line F _N-1 in FIG. 2A, and the region of interest above it is at the position shown by the solid line R _N-1 . . From this state, the operator operates the X-ray tube 21 and the I.D.
I. It is assumed that at least one of 25 and the top plate 24 is moved. As a result, the X-ray irradiation field is moved. When this movement occurs, the speed detectors 31a and 31b output signals according to the moving direction and the moving speed to the prediction calculation unit 35, so that the prediction calculation unit 35 recognizes that the irradiation field has moved, The moving direction and moving distance (in pixel units) of the irradiation field in the Nth frame, which is the next frame, are estimated.

It is assumed that the predicted position, that is, the position of the irradiation field of the Nth frame is the position shown by the solid line F _N shown in FIG. 2 (b). This moving direction and moving distance can be recognized as a shift of pixels forming the irradiation field. That is, FIG.
In the case of (b), the irradiation field F _{N−1 of the N−} 1th frame
Is m in the x-axis direction (for example, the direction orthogonal to the body axis of the patient)
It is predicted that the entire pixel is moved to become the irradiation field F _N of the _Nth frame. Based on the region of interest R _N-1 which has been previously designated as the deviation of the pixel (m pixels), a region of interest F _N R _N as shaded area R _{N 'enclosed} by a dotted line in FIGS. 2 (a) Is calculated.

As long as the area of interest is moved, the area of interest is estimated by the irradiation field F _N of the _Nth frame and the next _N fields.
The same applies to the irradiation field F _{N−1 of the} + _1st frame.
Further, when the image of the irradiation field is not moved, the current frame (for example, N-1th) and the next frame (for example, Nth) are overlapped by 100%.

Further, the irradiation field is moved by moving the X-ray tube 21 and the I.D. I. 25 or the movement of the top plate 24, and the X-ray tube 21 and the I.D. I. 25 or the top plate 24 moves at the maximum allowable speed, the region of interest in the next frame is the X-ray tube 21.
And I. I. 25, or the moving direction and moving speed of the tabletop 24 and the region of interest designated by the region of interest designating unit 37 in the current frame are set to be predictable.

Thus, from the image data of F _N-1 to F
_When R _N ′ corresponding to the region of interest R _N in _N is estimated, the image data of the region of interest R _N ′ is sent to the adjustment coefficient calculator 36. The calculation unit 36 calculates the brightness and the contrast adjustment coefficient for the image data of the Nth frame based on the image data (pixel value) of the sent area.

As described above, while the adjustment coefficient for the image data of the Nth frame is calculated from the image data of the (N-1) th frame, the image data of the Nth frame is stored in the image processing unit 33 and the frame. It is input to the memory 34.

In the image processor 33, the adjustment coefficient calculator 36
The brightness and contrast adjustment processing is performed on the image data of the N-th frame using the adjustment coefficient supplied from. The image data whose brightness and contrast have been adjusted is sent to the display 39 via the D / A converter 38 and is displayed in real time as a perspective image of the Nth frame.

On the other hand, the brightness and contrast adjustment coefficient for the image data of the (N + 1) th frame are calculated from the image data (Nth frame) subsequently stored in the frame memory 34. Then, in the image processing device 33, the image data of the (N + 1) th frame is image-adjusted by the adjustment coefficient based on the estimated own image data. The same process is repeated thereafter.

Further, when the detection values of the velocity detectors 31a and 31b are zero, that is, when the irradiation field is not moved, the above-mentioned regions R _N ′ and R _N−1 overlap _{each other} by 100%. Also at this time, the adjustment coefficient is simply calculated based on the image data of the area R _N ′, and the image processing is performed.

As described above, in this embodiment, the region of interest on the image data of the next frame is estimated from the moving velocity data of the irradiation field and the current region of interest, and the image data of the current frame corresponding to this region of interest is estimated. Is used to obtain an estimated image adjustment coefficient for the image data of the next frame. And
Using this adjustment coefficient, the brightness and contrast adjustment processing of the image data of the next frame, that is, the self image is performed.

As a result, the perspective image displayed on the display 39 is a high-quality image having a desired brightness and contrast because the brightness and contrast adjustment processing is appropriately performed on the self-image. . This makes it easy to operate the catheter and the like.

In addition, by performing the estimation process for the next frame while performing the image adjustment process on the self-image in this way, the frame of the image data to be processed by the image processing unit 33 is stored in the frame memory. The frame of the image data stored in 34 can be advanced by one frame. As a result, the frame memory (frame memory 10a in FIG. 3) in the image processing unit, which is seen in the above-described conventional apparatus, becomes unnecessary, so that the perspective image displayed on the display 39 and the image actually collected are There is no frame delay between them. This shortens the time from the collection of images to the display of processed images.

Therefore, even when the catheter is operated while seeing the fluoroscopic image, it is possible to surely eliminate the misalignment and discomfort between the displayed image and the actual operation. In particular, when the X-ray irradiation field is moved, conventionally, there is a large sense of discomfort due to the shift between the display image and the actual operation. However, according to the present embodiment, such a situation can be surely eliminated, and the operational trouble caused by the conventional frame delay can be avoided.
Enables stable and efficient operation. In addition, the burden on the operator is greatly reduced.

In the above embodiment, the case where the brightness and the contrast are automatically processed as the image processing is explained. However, in the present invention, other filter processing such as spatial filtering adjustment and temporal filtering may be performed. It may be.

[0049]

As described above, the X-ray fluoroscopic diagnosis apparatus of the present invention adjusts the image when the X-ray irradiation field is moved to obtain a fluoroscopic image while performing image adjustment processing such as brightness and contrast adjustment. The position of the region of interest in the next frame is estimated, the optimum adjustment factor for the image data of the next frame is calculated on the image data of the current frame, and the adjustment factor is used for the next frame. Since the image adjustment processing is performed, an appropriate perspective image can be quickly obtained.

Thus, the frame delay between the displayed fluoroscopic image and the actual operation (for example, the catheter operation performed while looking at the fluoroscopic image) can be eliminated, and the shift in the sense of operation due to the frame delay can be eliminated. . Therefore, it is possible to efficiently perform a desired operation while observing a high-quality perspective image. In particular, in the past, when the irradiation field was moved, a feeling of discomfort due to a frame delay was large, but according to the present invention, such a feeling of discomfort can be reliably eliminated, and the operator's burden is reduced and fluoroscopy is possible. It can contribute to the improvement of various work efficiency.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an X-ray fluoroscopic diagnosis apparatus according to an embodiment of the present invention.

FIGS. 2A and 2B are diagrams illustrating a prediction calculation of an image in a region of interest of a next frame according to an embodiment.

FIG. 3 is a block diagram showing an example of a conventional X-ray image diagnostic apparatus.

[Explanation of symbols]

 21 X-ray tube 21a Variable diaphragm device 22 X-ray control device 23 Subject 24 Top plate 25 Image intensifier (II) 26 Imaging device 31a, 31b Velocity detector 32 A / D converter 33 Image processing unit 33a Image processing circuit 33b Image adjustment circuit 34 Frame memory 35 Prediction calculation unit 36 Adjustment coefficient calculation unit 37 Region of interest designation unit 38 D / A converter 39 Display s Drive signal

Claims (2)

[Claims] 1. An X-ray irradiating unit that irradiates X-rays toward a diagnostic region of a subject, and a converting unit that converts the X-rays that have passed through the subject into image data. In an X-ray fluoroscopic diagnostic apparatus which has been subjected to predetermined image processing and which is to display the image data as a fluoroscopic image on a display, storage means for temporarily storing the image data converted by the conversion means for each frame, Detecting means for detecting the moving direction and moving speed of the radiation field of the line with respect to the object, designating means for designating a region of interest in the image data, detected value of the detecting means and the interest designated by the designating means. Region estimation means for estimating a region to be a region of interest in the next frame based on the region, and image data of the storage means corresponding to the region of interest estimated by the region estimation means Adjustment coefficient calculation means for calculating an image adjustment coefficient based on the image adjustment coefficient, and image adjustment means for performing necessary image adjustment according to the image adjustment coefficient calculated by the adjustment coefficient calculation means on the image data converted by the conversion means. An X-ray fluoroscopic diagnosis apparatus comprising: 2. The X-ray fluoroscopic diagnosis apparatus according to claim 1, wherein the image adjusting means is means for adjusting the brightness and contrast of the fluoroscopic image.