JPH06292085A - Method and device for processing radiograph - Google Patents

Abstract

PURPOSE:To improve the operability by discriminating whether or not a bottom hold image is obtained so as to obtain a desired road map from the result of discrimination. CONSTITUTION:When a mask picture generation is finished, injection of a contrast medium of angiogrphy is commanded to the operator from the device. When a 1st road map image is desired to be obtained, the operator injects the contrast medium of angiograply to a reagent and a comparator 34 and a 2nd picture memory 35 are used to generate a vein picture (bottom hold picture) by the bottom hold method. On the other hand, when a 2nd road map image is desired to be obtained, 1st radiography is finished without obtaining the bottom hold picture. The radiograph in 2nd and succeeding radiography is given to an A/D converter 22 and a logarithmic transformation device 39 and the processed signal is fed to a subtractor 40. The subtractor 40 subtracts the radiograph from the mask picture or the bottom hold picture and analog picture data are subject to D/A conversion by a D/A converter 24 and the result is outputted to a TV monitor 50.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing method and apparatus for cardiovascular radiation diagnosis, and more particularly to a radiation image processing method for obtaining a roadmap image as a support means for guiding a catheter to a target site of the subject. And its device.

[0002]

2. Description of the Related Art In a radiographic image processing apparatus, when operating a blood vessel catheter by X-ray fluoroscopy using a typical X-ray diagnostic apparatus as radiation, the operator performs X-ray fluoroscopy of the subject and examines the blood vessels of the subject. This is done by inserting a catheter and advancing this catheter to the target site. When this catheter operation is performed, a blood vessel image is added to the fluoroscopic image by performing image processing on the fluoroscopic image, or a predetermined X-ray image from the fluoroscopic image (for example,
A method that indicates the direction in which the catheter advances by subtracting the mask image) is called the road map method. In the actual clinical practice, the following two types of roadmap methods are used properly.

The first roadmap method is a method of creating a blood vessel image by flowing a contrast agent into a blood vessel when creating a mask image in order to confirm the direction of the blood vessel for advancing the catheter, and superposing the catheter on the blood vessel image. Is. This first
The roadmap method will be described with reference to FIG.

As shown in FIG. 4, at time t1, fluoroscopy is started to create a mask image. And time t2
In, a blood vessel contrast agent is injected into the blood vessel, and the blood vessel is traced by the bottom hold method to create a blood vessel image (this image may be referred to as “bottom hold image” for convenience). Once the blood vessel image is obtained, the fluoroscopy is turned off once at time t3.

At time t4, the fluoroscopic image is turned on again, and by subtracting the blood vessel image as a mask image from the fluoroscopic image, a subtraction image showing the blood vessel and the catheter can be obtained. As described above, the road map by the first road map method (hereinafter, referred to as “first road map image”) is obtained.

The second roadmap method is a method of operating a catheter with a fluoroscopic image of only the moving catheter in a complete subtraction image. The second roadmap method will be described with reference to FIG.

As shown in FIG. 5, in this case, the on / off operation of X-ray fluoroscopy is not particularly required. In this second roadmap method, when X-ray fluoroscopy is turned on, a mask image is formed by addition. By taking the arithmetic mean of the mask images obtained by this addition, noise in the mask image is reduced and the catheter can be easily identified.

After the mask image is created, X-ray fluoroscopy is performed while inserting the catheter, the mask image is subtracted from the fluoroscopic image, and a road map in which only the catheter is displayed (hereinafter referred to as "second road"). Map Statue "
Referred to as) can be obtained.

The first and second roadmap methods described above are used as necessary, but the first and second roadmap methods need to be repeatedly switched depending on the diagnostic situation. . However, in the conventional radiographic image processing method and its apparatus, it is necessary to switch between the first and second roadmap methods using an operation panel or the like, so that the operator holding the catheter in both hands can perform the switching operation. It was very troublesome.

[0010]

As described above, conventionally, it is necessary to switch the first and second roadmap methods by using the operation panel or the like, so that the operator who holds the catheter in both hands can switch the method very much. It was troublesome.

The present invention has been made under the above circumstances, and an object of the present invention is to provide a radiation image processing method and apparatus for easily obtaining a roadmap image by a desired roadmap method.

[0012]

The present invention has taken the following means in order to solve the above problems.

The radiographic image processing method of the present invention comprises the first step of irradiating a subject before injection of a vascular contrast agent with radiation to obtain mask image data, and, if necessary, applying a vascular contrast agent to the subject. The second step of injecting and obtaining the bottom hold image data by holding the minimum value of the fluoroscopic image data of a plurality of frames obtained by irradiating the subject with radiation, and a fluoroscopic image by inserting a catheter into the subject In the third step of obtaining data and in the second step, if the bottom hold image data is obtained by injecting the blood vessel contrast agent, the first step is performed based on the bottom hold image data and the fluoroscopic image data. When a roadmap image of the above is obtained and the blood vessel contrast agent is not injected, a second road map is created based on the mask image data and the fluoroscopic image data created in the first step. And a fourth step of obtaining a road map image.

The radiographic image processing apparatus of the present invention is a means for irradiating a subject before injection of a blood vessel contrast agent with radiation to obtain mask image data, and, if necessary, injecting a blood vessel contrast agent into the subject. A means for obtaining bottom hold image data by holding a minimum value of the fluoroscopic image data of a plurality of frames obtained by irradiating the subject with radiation; and a catheter is inserted into the subject to obtain fluoroscopic image data. Determining whether or not the blood vessel contrast agent has been injected, and in the case of injecting the blood vessel contrast agent, obtains a first roadmap image based on the bottom hold image data and the fluoroscopic image data,
A means for obtaining a second roadmap image based on the mask image data and the fluoroscopic image data when the blood vessel contrast medium is not injected is provided.

[0015]

As a result of taking the above-mentioned means, the following effects occur.

According to the radiation image processing method and the apparatus therefor of the present invention, it is possible to determine whether or not a bottom hold image has been obtained, and obtain a desired roadmap image based on the result. Therefore, the operation such as the selection of the roadmap method by the operator is eliminated, and the operability is improved. Further, the improved operability shortens the inspection time. In addition, since the operability is improved, the burden on the operator can be reduced.

[0017]

1 is a schematic block diagram of a radiation image processing apparatus according to an embodiment of the present invention. FIG. 2 is a diagram for explaining the operation of the radiation image processing apparatus of the present invention.

The fluoroscopy switch 10 is a switch for turning on / off the X-ray fluoroscopy, and an on / off fluoroscopy command signal from the fluoroscopy switch 10 is output to the X-ray controller 11. The X-ray control device 11 sends a control signal for generating X-rays based on the fluoroscopic command signal input from the fluoroscopic switch 10 to the X-ray tube 12, the CPU 25 in the image processing device 20 described later in detail, Supply to.

The X-ray tube 12 irradiates the subject 13 with X-rays based on the control signal supplied from the X-ray controller 11. The X-ray transmitted through the subject 13 is input to the image intensifier 14 (hereinafter, referred to as “II”), and the I.D. I. At 14, it is converted into an optical image. TV camera 1
6 through the optical system 15 such as a lens. I. The optical image incident from 14 is converted into a TV video signal, and the TV video signal is supplied to the image processing device 20 as analog image data.

The image processing device 20 is a device for performing image processing on image data input from the TV camera 16, and includes an analog / digital converter 22 (hereinafter referred to as "A / D converter").
Image processing unit 30 and this image processing unit 30
And a digital / analog converter 24 (hereinafter, referred to as "D / A converter").

The A / D converter 22 converts analog image data from the TV camera 16 into digital image data. The digital image data from the A / D converter 22 includes the adder 31, the comparator 34, and the third logarithmic converter 39.
And are output as needed. For example, the output data of the A / D converter 22 is added by the adder 3 when the mask image is created.
1 to the comparator 34 when the bottom hold image is created,
At the time of the perspective after the first time, it is output to the third logarithmic converter 39.

When the mask image is created, the A / D converter 2
The output of 2 is input to the adder 31. The adder 31 is an A / D
At the same time as the mask image data is sequentially fetched from the converter 22 for each frame, the mask image data and the mask image data from the first image memory 32 are added, and the added data is output to the first image memory 32. First image memory 3
2 writes the mask image data output from the adder 31 to update the contents of the first image memory 32. By repeating these operations N times, N pieces of added mask image data 42 are stored in the first image memory. This mask image data is divided by a number of times of addition (N times in this case) by a divider (not shown), the average of the mask image data is obtained, and the image data obtained by performing this average is used as a mask image. To do. The first logarithmic converter 33 logarithmically converts the mask image data from the first image memory 32, and supplies the logarithmically converted mask image data to the first subtractor 37 or the third image memory 38.

When the bottom hold image is created, the A / D
The output of the converter 22 is input to the comparator 34. Comparator 34
Compares the image data from the A / D converter 22 and the image data stored in the second image memory 35 with a pixel value for each pixel, and holds the minimum pixel value to hold the second image memory 35. The contents of the second image memory 35 are updated by writing in () (this is referred to as "bottom hold"). The second logarithmic converter 36 logarithmically converts the bottom hold image data from the second image memory 35, and supplies the logarithmically converted bottom hold image data to the first subtractor 37 or the third image memory 38.

When creating the road map, the output of the A / D converter 22 is input to the third logarithmic converter 39. Further, the third image memory 38 stores image data of either the mask image data stored in the first image memory 32 or the bottom hold image data stored in the second image memory 35.

The second subtractor 40 subtracts the perspective image data from the third logarithmic converter 39 and the image data stored in the third image memory 38 to obtain a desired roadmap image from the D / A converter. Supply to 24. TV monitor 5
0 displays the desired roadmap image that has been analog converted by the D / A converter 24. The operation of the radiation image processing apparatus of the present invention configured as described above will be described with reference to FIG.

First, when the first fluoroscopy is turned on (time t1), the adder 31 sequentially takes in the mask image data from the A / D converter 22 for each frame, and at the same time
The mask image data from the D converter 22 and the mask image data from the first image memory 32 are added and output to the first image memory 32. The first image memory 32 sequentially updates the mask image data while writing the added mask image data. When these operations are repeated N times, N pieces of added mask image data are obtained. After that, N mask image data are arithmetically averaged to obtain a mask image. By this operation, a mask image with a good S / N ratio can be obtained.

When the mask image has been created, time t2
At, the device directs the operator to inject a contrast agent. In this case, in order to obtain the first roadmap image, the operator injects a blood vessel contrast agent into the subject and uses the bottom hold method to compare the comparator 34 and the second image memory 3 with each other.
5 and blood vessel image (hereinafter, “bottom hold image”)
Called). When it is desired to obtain the second roadmap image, it is not necessary to inject a blood vessel contrast agent to obtain a bottom hold image, so the first fluoroscopy is terminated. The image during the period from t2 to t3 is displayed as follows. The mask image is converted by the first logarithmic converter 33, and the bottom hold image is converted by the second logarithmic converter 36, and then subtracted by the first subtractor 37. After that, the subtracted image is directly D / D from the third image memory 38.
It is input to the A converter 24, converted into a video signal again by the D / A converter 24, and the subtraction image is displayed on the TV monitor 50. At time t3, the first fluoroscopy is turned off.

In the second and subsequent perspectives, 2 at time t4
A case where the second fluoroscopy is started will be described. The second and subsequent perspective images are input from the A / D converter 22 to the third logarithmic converter 39, and after being logarithmically converted by the third logarithmic converter 39,
Input to the second subtractor 40. The second subtractor 40 subtracts the fluoroscopic image from either the mask image or the bottom hold image and outputs the subtracted image to the D / A converter 24. The D / A converter 24 converts the subtracted image data into analog image data and outputs it to the TV monitor 50. Then, the TV monitor 50 displays the first or second roadmap image.

In this case, the device of the present invention is configured to select the first or second roadmap image depending on the period from t2 to t3. That is, in order to obtain the first roadmap image by the first roadmap method, it is necessary to create the bottom hold image.
It takes a time (for example, several seconds) from when the injection instruction of the blood vessel contrast agent is issued to when the blood vessel contrast agent is injected and the bottom hold image is obtained. On the contrary, when it is desired to obtain the second roadmap image, it is not necessary to inject the vascular contrast medium at the time t2, and thus the first fluoroscopy can be finished at this point. Therefore, it is possible to determine whether the operator is going to perform the first roadmap image or the second roadmap image based on the time required from time t2 to time t3. Therefore, it is necessary from time t2 to time t3. Depending on the time taken, either the first roadmap image or the second roadmap image is automatically selected.

When the first roadmap method is selected, the bottom hold image in the second image memory 35 is
After being converted by the logarithmic converter 36, the second logarithmic converter 36
Directly into the third image memory 38. When the second roadmap method is selected, the mask image obtained by the addition passes through the first image memory 32, the first logarithmic converter 33, and the first
It directly enters the third image memory 38 from the logarithmic converter 33.

Then, either the bottom hold image or the mask image stored in the third image memory 38 and the perspective image input from the third logarithmic converter 39 are combined with the second subtractor 40.
Is subtracted, input to the D / A converter 24, converted into an analog image by the D / A converter 24, and then input to the TV monitor 50 to display a desired roadmap image on the TV monitor 50. To be done.

As described above, according to the radiographic image processing apparatus of the present invention, whether the vascular contrast agent has been injected is determined based on the time from the instruction to inject the vascular contrast agent to the end of the first fluoroscopy. Alternatively, which road map method of the second road map method is selected is automatically determined to obtain a desired road map image. Therefore, the operation such as the selection of the roadmap method by the operator is eliminated, and the operability is improved. Further, the improved operability shortens the inspection time. In addition, since the operability is improved, the burden on the operator can be reduced. Next, the radiation image processing method of the present invention will be described with reference to FIG. FIG. 3 is a flowchart showing a radiation image processing method according to an embodiment of the present invention.

First, the operator selects the road map and turns on the first fluoroscopic operation (step S1). The fluoroscopic images are added for a predetermined time, and the arithmetic mean of the fluoroscopic images is taken to create a mask image before the injection of the blood vessel contrast agent (step S2). The reason that the fluoroscopic images are added in step S2 is to improve the S / N ratio.

When the mask image has been created, the operator is instructed to inject the blood vessel contrast medium (step S3). This injection instruction is performed, for example, by displaying a symbol indicating injection of a blood vessel contrast agent on the TV monitor or by notifying with a buzzer. Based on the above instruction, the operator determines whether to inject a blood vessel contrast agent into the subject (step S4).

In step S4, when the angiographic agent is injected into the subject, that is, when the first roadmap image is obtained, the operator continues the fluoroscopy and injects the angiographic agent into the subject ( Step S5). By using the bottom hold method, the blood vessel contrast agent injected into the blood vessel is held at the minimum value at each pixel from consecutive images, and processing is performed to leave the trajectory of the blood vessel contrast agent, creating a bottom hold image. Go (step S6). In this case, the operator observes the flow of the blood vessel contrast agent in real time on the TV monitor. That is, this period is step S
The mask image created in 2 and the bottom hold image are subtracted in real time so that the operator can know how far the blood vessel contrast agent has reached. When the blood vessel contrast agent reaches the target blood vessel, the operator ends (turns off) the first fluoroscopy (step S7).

In step S4, the blood vessel running is not necessary, but the S / N is used for the purpose of easily identifying the catheter.
When displaying the second roadmap image with a high ratio, that is, when the angiographic agent is not injected into the subject, the operator sets 1
The fluoroscopy for the second time is ended (off) as it is (step S
7).

After the end of step S7, the time required from step S4 to step S7 is a predetermined time (for example, 3
Second) is determined (step S8). It should be noted that this time can be adjusted by the operator.

In step S8, if the blood vessel contrast agent is injected after step S4, the time required from step S4 to step S7 is considered to be 3 seconds or more. Therefore, it is determined that the blood vessel contrast agent has been injected, and the bottom hold image is masked. As the first roadmap image (step S
9). That is, in this case, in the second and subsequent fluoroscopy, the bottom hold image and the fluoroscopic image are subtracted to form a blood vessel image and an image of only the moving portion of the catheter.

On the other hand, in step S8, step S
When the time required from 4 to step S7 is as short as 1 to 2 seconds, it is determined that the blood vessel contrast agent has not been injected, and the second roadmap image is obtained using the mask image as a mask (step S10). Thus, when fluoroscopy is turned off immediately when an instruction to inject an angiographic agent is given, an image of only the catheter is obtained. That is, in this case, in the second and subsequent fluoroscopy, since the mask image and the fluoroscopic image obtained by the addition in step S2 are subtracted from each other to perform the road map, only the portion where the catheter has moved is imaged. become. In this case, the mask image is obtained by addition averaging, so the image has a good S / N ratio.

According to the method described above, the road map images obtained by the first and second road map methods are automatically obtained without the operator having to operate them by themselves, so that the operability is dramatically improved. Further, the improved operability shortens the inspection time. In addition, since the operability is improved, the burden on the operator can be reduced. The present invention is not limited to the above embodiment.

For example, in the above embodiment, the subtraction method was used as the means for obtaining the first and second roadmap images. However, for example, in the second roadmap method, the blood vessel image after the injection of the blood vessel contrast medium is obtained. It is also possible to use a method of extracting only, superimposing it on the catheter image, and displaying it.

Further, in the above-mentioned embodiment, as a judgment criterion when selecting the first or second road map method,
Although the time for ending the first fluoroscopy after the instruction of the injection of the blood vessel contrast medium is adopted, the time is not limited to this. For example,
It is also possible to select either the first or the second roadmap method by comparing the brightness of the mask image and the brightness of the image at the end of the first fluoroscopy to determine whether or not the blood vessel contrast agent is injected.

Further, in the present invention, the apparatus automatically determines either the first or the second roadmap method,
Although it is configured to display the desired roadmap image, if a roadmap method different from the one intended by the operator is erroneously selected, manual operation by the operator causes
It is also possible to add a function that modifies the selection of the roadmap method. Of course, various modifications can be made without departing from the scope of the present invention.

[0044]

According to the present invention, the following effects can be obtained.

According to the radiation image processing method and the apparatus therefor of the present invention, it is possible to determine whether or not a bottom hold image has been obtained, and obtain a desired roadmap image based on the result. Therefore, the operation such as the selection of the roadmap method by the operator is eliminated, and the operability is improved. Further, the improved operability shortens the inspection time. In addition, since the operability is improved, the burden on the operator can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of a radiation image processing apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining the operation of the radiation image processing apparatus of the present invention.

FIG. 3 is a flowchart showing a radiation image processing method according to an embodiment of the present invention.

FIG. 4 is a diagram showing an example of a road map.

FIG. 5 is a diagram showing another example of a road map.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Transparent switch, 11 ... X-ray controller, 12 ... X-ray tube, 13 ... Subject, 14 ... Image intensifier (II), 15 ... Optical system, 16 ... TV camera, 2
0 ... Image processing device, 22 ... Analog / digital converter (A / D converter), 24 ... Digital / analog converter (D / A converter), 25 ... CPU, 30 ... Image processing unit,
31 ... Adder, 32 ... First image memory, 33 ... First logarithmic converter, 34 ... Comparator, 35 ... Second image memory, 36 ...
2nd logarithmic converter, 37 ... 1st subtractor, 38 ... 3rd image memory, 39 ... 3rd logarithmic converter, 40 ... 2nd subtractor, 50
... TV monitor.

Claims (2)

[Claims] 1. A first step of irradiating a subject prior to injection of a blood vessel contrast agent with radiation to obtain mask image data, and, if necessary, injecting a blood vessel contrast agent into the subject to perform the first step. A second step of obtaining the bottom hold image data by holding the minimum value of the fluoroscopic image data of a plurality of frames obtained by irradiating the subject with radiation, and a third step of inserting a catheter into the subject to obtain the fluoroscopic image data. In the second step, when the blood vessel contrast agent is injected to obtain the bottom hold image data, a first road map image is obtained based on the bottom hold image data and the fluoroscopic image data, When the blood vessel contrast agent is not injected, a fourth step for obtaining a second roadmap image based on the mask image data and the fluoroscopic image data created in the first step. Radiographic image processing method characterized by the, the equipped. 2. Means for obtaining mask image data by irradiating a subject prior to injection of a vascular contrast agent, and, if necessary, injecting a vascular contrast agent into the subject so as to irradiate the subject with radiation. Means for obtaining the bottom-hold image data by holding the minimum value of the fluoroscopic image data of a plurality of frames obtained by irradiating the subject, and obtaining the fluoroscopic image data by inserting the catheter into the subject, and injecting the angiographic agent. When the blood vessel contrast agent is injected, the first roadmap image is obtained based on the bottom hold image data and the fluoroscopic image data, and the blood vessel contrast agent is injected. A radiation image processing apparatus comprising: a means for obtaining a second roadmap image based on the mask image data and the fluoroscopic image data when there is no such image.