JP4181342B2 - X-ray diagnostic imaging equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an X-ray diagnostic imaging apparatus, and in particular, a digital subtraction angiography apparatus (hereinafter referred to as “a subtraction angiography apparatus for diagnosing a vascular disease by detecting and displaying a difference between images before and after contrast medium injection into a blood vessel”. The present invention relates to a technique effective when applied to a "DSA apparatus".
[0002]
[Prior art]
The conventional DSA apparatus subtracts a reference image (hereinafter referred to as “mask image”) when no contrast agent is contained and an image (hereinafter referred to as “live image”) containing the contrast agent, Only a blood vessel image containing a contrast agent can be displayed. Thereby, it is possible to eliminate the influence that the blood vessel image becomes difficult to see due to the bone behind the blood vessel.
[0003]
Further, for example, in order to grasp the positional relationship between the blood vessel image and the bone, a subtraction process (hereinafter referred to as “landmark”) for displaying the bone thinly by adjusting the subtraction ratio of the mask image may be performed.
[0004]
For the landmark, the ratio of the mask image to be subtracted from the live image is adjusted. The ratio ranges from 0% to 100%. That is, it is possible to display between a complete live image (when 0%) and a complete subtraction image (when 100%). Also, since the values of the window width (Windows Width: hereinafter simply referred to as W / W) and the window level (Window Level: hereinafter simply referred to as W / L) are different between the normal live image and the subtraction image, the ratio of the landmarks is changed. After the change, W / W and W / L were manually adjusted.
[0005]
[Problems to be solved by the invention]
However, in the above-described prior art, it is difficult to perform the inspection efficiently because it takes time and labor to adjust manually.
In addition, there is a problem in that it cannot cope with an unexpected movement of the subject, and a part of the original effective image information is also hidden.
[0006]
An object of the present invention is to provide a technique capable of automatically setting a ratio (landmark ratio) of a mask image to be subtracted from a live image when a subtraction image is formed.
Another object of the present invention is to provide a technique capable of automatically setting appropriate W / W and W / L for changes in the proportion of landmarks.
The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.
[0007]
[Means for Solving the Problems]
The outline of the invention disclosed in the present application will be briefly described as follows. The present invention relates to an X-ray source for irradiating a subject with X-rays, an X-ray image means for visualizing X-rays transmitted through the subject, and an image signal A converted from image signals from the X-ray image means. / D conversion means, image recording means for recording the image data from the A / D conversion means, arithmetic processing means for arithmetic processing of the image data, and image display for displaying the arithmetic processing result of the arithmetic processing means Means for selecting a ratio (landmark ratio) of a mask image to be subtracted from a live image when the image data is arithmetically processed to form and display a subtraction image. When the landmark ratio is selected based on a characteristic line of the landmark ratio set from a plurality of appropriate window widths and window levels of the mask image and the live image, an appropriate window is selected. Characterized by comprising a means for setting the window width and window level.
[0008]
That is, using the appropriate W / W and W / L of the mask image (sub-image) and the live image, the W / W and W / L corresponding to the landmark ratio representing the middle are calculated. Then, the calculated W / W and W / L are applied simultaneously with the change of the landmark ratio.
[0009]
Conventionally, two steps of changing the landmark ratio and changing the W / W and W / L are required, but this can be performed in one step of changing the landmark ratio only. That is, it is not necessary to manually set W / W and W / L, which was necessary when changing the landmark ratio.
Also, since appropriate W / W and W / L are used, the image does not become dark even if the landmark ratio is changed, and it is possible to work without a sense of discomfort.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings together with embodiments (examples) of the invention.
[0011]
FIG. 1 is a block diagram showing a schematic configuration of an X-ray image diagnostic apparatus according to an embodiment of the present invention.
As shown in FIG. 1, the X-ray diagnostic imaging apparatus of the present embodiment has an X-ray source (X-ray tube apparatus) 1 that irradiates a subject with X-rays and an X-ray that images X-rays that have passed through the subject. A line image means (for example, image intensifier: II) 2, an A / D conversion means (A / D converter) 3 for converting a video signal from the X-ray image means 2 into digital image data, An image recording means (image memory) 4 for recording digital image data from the A / D conversion means 3, an arithmetic processing means (CPU) 5 for arithmetic processing of the image data, and an arithmetic processing result of the arithmetic processing means 5 An image display means (image display device) 6 for displaying is provided.
[0012]
The X-ray image diagnostic apparatus of the present embodiment irradiates a subject with X-rays from the X-ray source 1 and visualizes the X-rays transmitted through the subject by the X-ray image means 2. The video signal from the X-ray image means 2 is converted into digital image data by the A / D conversion means 3, and this digital image data is recorded in the image recording means 4.
[0013]
A mask image (sub-image) when no contrast agent is contained is photographed by the above operation procedure, and the mask image data is recorded in the image recording means 4. Similarly, a live image containing a contrast medium is taken, and the live image data is recorded in the image recording means 4.
[0014]
Mask image data and live image data recorded in the image recording means 4 are read out and input to the arithmetic processing means (CPU) 5. The arithmetic processing means 5 subtracts (subtracts) the mask image when no contrast agent is contained and the live image containing the contrast agent. Thereby, only the image of the part containing the contrast agent can be displayed. For example, in the case of a DSA apparatus, only a blood vessel image containing a contrast agent can be displayed, and the influence of making the blood vessel image difficult to see due to the bone behind the blood vessel can be eliminated.
[0015]
Here, for example, in order to grasp the positional relationship between the blood vessel image and the bone, the subtraction processing landmark for thinly displaying the bone may be performed by adjusting the subtraction ratio of the mask image.
[0016]
For the landmark, the ratio of the mask image to be subtracted from the live image is adjusted. The ratio ranges from 0% to 100%. That is, it is possible to display between a complete live image (when the landmark ratio is 0%) and a complete subtraction image (when the landmark ratio is 100%).
[0017]
Further, the values of W / W and W / L are different between the normal live image and the subtraction image. For example, FIG. 2 shows a case where W / W and W / L are not changed when the landmark ratio is changed from 100% to 0%. 2A shows a case where the landmark ratio = 100%, W / W = 800, and W / L = −200, and FIG. 2B shows a landmark ratio = 50%, W / W = 800, W The case of / L = −200 is shown, and (c) shows the case of the landmark ratio = 0%, W / W = 800, and W / L = −200.
[0018]
FIG. 3 shows a case where W / W and W / L are changed. 3A shows a case where the landmark ratio = 100%, W / W = 800, and W / L = −200, and FIG. 3B shows a landmark ratio = 50%, W / W = 2400, W The case of / L = −1100 is shown, and (c) shows the case of landmark ratio = 0%, W / W = 4000, and W / L = −2000.
[0019]
It is assumed that the proper W / W and W / L of the mask image (sub-image) are 800 and −200, respectively, and the proper W / W and W / L of the live image are 4000 and −2000, respectively.
[0020]
In this case, if W / W and W / L are not changed, the live image is displayed as W / W and W / L of the mask image (sub-image), as shown in FIG. Will be blackish throughout.
[0021]
On the other hand, when the landmark is 0%, when the appropriate W / W and W / L of the live image are used, the optimum display as shown in FIG.
[0022]
The method for determining the appropriate W / W and W / L is, for example, shown in FIG. 4 (appropriate landmark ratio-W / W characteristic chart) and FIG. 5 (appropriate landmark ratio-W / L characteristic chart). Appropriate W / W and W / L are automatically set by simply selecting and setting an appropriate landmark ratio between 0% and 100% using the landmark ratio characteristic line. can do.
[0023]
In this way, by changing the value when the appropriate value of the mask image (sub-image) and the appropriate value of the live image are linearly connected according to the landmark ratio, the subtraction image of the subtraction image is always obtained by appropriate landmark processing. Display can be made.
[0024]
The invention made by the present inventor has been specifically described based on the embodiment of the invention, but the invention is not limited to the embodiment of the invention and does not depart from the gist of the invention. Of course, various changes can be made.
[0025]
【The invention's effect】
The effects obtained by the invention disclosed in the present application will be briefly described as follows.
According to the present invention, by appropriately setting the appropriate W / W and W / L at the same time as changing the landmark ratio, appropriate landmark processing can always be performed, so that an appropriate subtraction image can be displayed without a sense of incongruity. can do.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic configuration of an X-ray image diagnostic apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram showing a subtraction image when the landmark ratio is changed without changing W / W and W / L.
FIG. 3 is a diagram showing a subtraction image when the landmark ratio is changed while changing W / W and W / L according to the present embodiment.
FIG. 4 is a characteristic diagram showing a relationship between an appropriate landmark ratio and W / W according to the present embodiment.
FIG. 5 is a characteristic diagram showing a relationship between an appropriate landmark ratio and W / L according to the present embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... X-ray source (X-ray tube apparatus) 2 ... X-ray image means (II)
3 ... A / D conversion means (A / D converter) 4 ... Image recording means 5 ... Arithmetic processing means (CPU) 6 ... Image display means (image display device)

Claims (1)

An X-ray source for irradiating a subject with X-rays, an X-ray image means for imaging X-rays transmitted through the subject, and an A / D conversion means for converting a video signal from the X-ray image means into image data having the an image recording means for recording the image data from the a / D converter, an arithmetic processing means for arithmetically processing the image data, and image display means for displaying the operation result of said arithmetic processing means In the X-ray diagnostic imaging apparatus, a means for selecting a ratio of a mask image (landmark ratio) to be subtracted from a live image when the image data is arithmetically processed to form and display a subtraction image, and the mask image based on the landmark ratio characteristic lines are set from a plurality of proper window width and window level of the live image, selecting the landmark proportions, proper window width X-ray image diagnosis apparatus characterized by comprising a means for setting the fine window level.

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