JPS5917331A - X-ray diagnostic apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an X-ray diagnostic apparatus that is used, for example, to measure ventricular volume, and is capable of reducing the burden of contrast agent injection on the heart of a subject.

[Technical background of the invention]

Conventionally, when measuring ventricular volume in circulatory system diagnosis, for example, a catheter is inserted into the ventricle through a blood vessel, a contrast agent is injected, and X-ray images are taken when the ventricle is at its maximum expansion and minimum contraction. Based on.

At that time, they did not take into account the quality of the image obtained, such as the shading and sharpness of the image, and the amount of contrast medium injected into the subject was changed and measured, but only based on the doctor's experience. The amount of contrast agent to be injected was decided based on intuition.

As a result, the obtained image data was not sufficient for subsequent image processing, and in order to obtain sufficient contrast and sharpness of the image, more contrast agent was injected than necessary. They were putting more burden on the subjects than necessary.

[Purpose of the invention]

The present invention was developed in view of the above circumstances, and it is possible to control the amount of contrast medium to be injected to an optimal amount in ventricular volume measurement, etc., thereby reducing the burden on the subject's heart as much as possible, and improving the image quality of subsequent images. Obtain enough data for processing.

[Summary of the invention]

That is, in order to achieve the above object, the present invention injects a contrast agent into the circulatory system (inside the ventricle) of a subject using a contrast agent injection device, and irradiates the subject with X-rays using an X-ray device to perform X-ray imaging. In the diagnostic apparatus, the image obtained by this X-ray photography is converted into image data by an image data conversion means, and the image data is processed to obtain information necessary for diagnosis. When the set injection volume is set to a predetermined minimum and an increase command is received, the set injection volume is increased by a predetermined amount, and when an injection command is received, the contrast medium is injected for the set injection volume. and a means for determining from the image data whether or not the image data due to the contrast agent can be distinguished from others, and if not, generating an instruction to increase the amount of contrast agent injection, and a means for generating an instruction to increase the amount of contrast agent injection, and means for detecting the state of cardiac motion, generating the contrast medium injection command in synchronization with ventricular diastole, and giving an imaging command to the X-ray device when the ventricle is expanding or contracting;
X-ray photography and contrast agent injection are performed in synchronization with cardiac motion, and the amount of contrast agent injected is kept to a minimum at first, and from the image data obtained at this time, it is necessary to determine whether it is possible to distinguish the image data of the required part from other image data. If the contrast agent cannot be identified, the amount of contrast agent is increased, and by repeating this process, the injection amount is automatically set to the minimum necessary amount so that there is no need to inject more than necessary. By injecting a contrast medium during ventricular diastole, it is possible to reduce negative Jfl and maintain safety during injection of a contrast medium in a subject.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

Figure 1 is a block diagram showing the configuration of this device.
Reference numeral 1 denotes an X-ray photographing device that emits X-rays according to an X-ray photographing command and obtains an X-ray image of the subject; an image input device that converts the image signal into a signal and digitizes the image signal as image data; 13, a storage device that stores this image data; 14;
15 is an image processing device that obtains image data from the storage device 13 and calculates the ventricular volume by calculating the area of the ventricular portion from this image data; It is determined whether or not the contrasted part of the organ can be distinguished from other parts in the image data, and if it is possible to distinguish it, it gives a command to the image processing device 14 to perform image processing, and if it is not possible to distinguish it, it Reference numeral 16 denotes an image judgment device that outputs a command to increase the amount of contrast injection, and 16 indicates an increase in the amount of contrast agent injection by a predetermined amount according to the instruction to increase the amount of contrast agent injection, and when the command for increasing the amount of contrast agent injection is received, an area corresponding to the increased amount is set. A contrast agent injection device 17 detects the movement of the ventricle based on biological signals such as electrocardiograms and heart sounds of the subject, and detects the diastole and systole phases of the ventricle from the inclination thereof. At the end of contraction, a contrast medium injection command is output and -! This is a synchronization device that outputs X-ray imaging commands when the ventricle contracts and when the ventricle dilates.

Next, the operation of this apparatus having the above configuration will be explained.

In synchronization with the heart motion of the subject, the synchronizer 17 outputs a contrast medium injection command at the end of ventricular contraction, and an X-ray imaging command at the time of ventricular contraction and ventricular expansion.

Then, according to the contrast medium injection command, the contrast medium injection device injects the set injection amount of contrast medium into the subject. This set injection amount is the minimum amount necessary for a predetermined contrast imaging at the initial stage, and is the minimum amount necessary for contrast imaging regardless of age, sex, physique, condition, and other conditions.

Since the contrast medium injection command is output at the end of ventricular systole, the actual contrast medium injection is performed at the beginning of ventricular diastole, making it possible to inject the contrast medium without incurring negative effects on the subject. You can do it.

On the other hand, since an X-ray imaging command is output when the ventricle expands or contracts, the X-ray imaging device 11 irradiates the subject with X-rays and obtains an X-ray image each time this command is received. This X-ray image is input to the image input device 12, where it is converted into image data.

The image input device 12 is composed of, for example, a television camera and an A/D (analog/digital) converter, and the image is converted by an image intensifier for converting an X-ray image to an optical image of the X-ray imaging device 11. An optical image is captured by a television camera and converted into an image signal, which is then ID-converted to image data and output.

This image data is sequentially stored in the storage device 13 and also provided to the image judgment device 15, and the image judgment device 15 uses the image data of the contrasted organ part based on the input image data to compare the image data of the other parts. It is determined whether or not it can be distinguished from the data, and if it is determined that it cannot be distinguished sufficiently, a command to increase the amount is output and given to the contrast medium injection device 16.

In response to this, the contrast medium injection device 16 changes the set value of the contrast medium injection amount to a value that is increased by a predetermined amount. When the synchronization device 17 receives a contrast medium injection command, the contrast medium for this newly set area is sent out and injected.

After that, repeat the above-mentioned series of actions again.

When the image judgment device 15 determines that the newly input image data can be discriminated, the image judgment device 15
gives a command to the image processing device 14, transfers control to the image processing device 14, and causes the image processing device 14 to execute image processing.

In this way, while determining the image condition, the amount of contrast agent injected is automatically increased sequentially to achieve the optimal image condition for image processing, and the amount increase is stopped when the optimal image is obtained, so There is no need to worry about injecting an excess amount of the agent than necessary, and since the contrast medium is injected during the diastolic phase of the ventricle when the internal pressure is low, the contrast medium injection pressure can be lowered. Therefore, it is not necessary to impose an undue burden on the subject, and since the amount of contrast medium injected is the minimum necessary amount, the stability of the subject can be maintained.

That is, contrast medium injection is performed by applying pressure from outside the body, which puts a burden on the subject during injection, so it is desirable to keep the amount of contrast medium to a small amount if possible. However, if the concentration of the contrast agent in the blood is low, sufficient contrast in the X-ray image cannot be obtained, which may cause problems in the subsequent image processing stage.
On the other hand, if the amount of contrast medium is increased more than necessary in order to obtain good enough data for image processing, the pressure during injection will have to be increased, which will put an unnecessary burden on the subject, and the A low blood concentration poses a danger to the human body, which is not desirable from a safety standpoint.

For the reasons mentioned above, the maximum amount of contrast medium that can be given to a subject is naturally determined by various conditions such as age, sex, physique, and condition. However, although it is convenient for image processing to always provide the maximum amount, it may actually be an excessive amount, and in that case, a smaller amount should be sufficient.

With the present invention, such an optimum amount can be achieved by using a small amount of contrast agent at first, and when sufficient image data cannot be obtained, increasing the amount of contrast agent and taking another image to obtain data from one image. This process is repeated to automatically determine the optimal amount, and ventricular volume is measured based on the image data obtained by imaging with the optimal amount of contrast agent. In addition, since the contrast medium is injected during the diastolic phase of the ventricle, combined with the synergistic effect of injecting the optimal amount of contrast medium, it is possible to avoid unnecessary burden on the subject, increasing life safety.

The operation of this apparatus has been described above, but now the image determination device 15, which is an important component in this apparatus, will be explained in more detail.

Here, as an example, we will focus on the density histogram of image data, and detect the peaks in the image of an organ photographed using a contrast agent, such as the left ventricle of the heart, etc., and calculate the peak value and standard deviation of the peak value. An example of determining whether or not it is necessary to adjust the injection amount of the agent will be shown.

FIG. 2 is a block diagram showing an example of the configuration of the image determination device 15. As shown in the figure, the image determination device 15 includes a frequency calculation device 2, a peak detection device 22, and a standard deviation calculation device 2.
3. It consists of a comparison and determination device 24.

Here, the frequency calculation device 21 calculates the frequency for each gray level of image data inputted from the image input device 12, and sequentially processes the inputted image data. Also,
The peak detection device 22 removes the frequency peak due to the background from the output of the frequency calculation device 2 using predetermined parameters, and calculates the peak on the histogram formed by the image data of the image of the organ part taken with the contrast agent. Find the peak value of.

Further, the standard deviation calculating device 23 ignores infrequent image data that is considered as noise according to a predetermined parameter, and standardizes the degree of clustering of frequencies around the peak determined by the peak detecting device 22. Find it as a deviation. Further, the comparison/judgment device 24 compares a pre-given parameter with the outputs of the previous HC peak detection device 22 and the standard deviation calculation device 23, and if the values are appropriate, gives a command to the image processing device 14. If the value is not appropriate, a command to increase the contrast medium injection amount is given to the contrast medium injection device 16 without transferring control to the image processing device 14.

In such a configuration, when image data for one image is sequentially input from the image input device 12, the frequency calculation device 2 integrates each image data for each gray level and calculates each gray level for the image data for one image. Calculate the frequency of FIG. 3 is a diagram showing an example of frequencies for each density level obtained in this way, and in the figure, 31 indicates a frequency peak due to the background, and 32 indicates a frequency peak due to a contrast agent.

As can be seen from the figure, the contrast agent image has a range of shading levels that is significantly different from the image portions of other compositions, and this is utilized here to distinguish the image data of the contrast agent portion from other image data. In particular, when the amount of contrast agent is appropriate, the distribution range of the image data of the contrast agent area by density level is narrow, so the data does not concentrate frequently in a specific range; conversely, when the amount of contrast agent is small Since the concentration of the contrast agent is low in , the distribution range of image data in the contrast agent portion is widened.

Therefore, the peak detection device 22 removes data in an unnecessary density level range other than the contrast agent portion, that is, corresponding to the background, from the frequency data for each density level obtained by the frequency calculation device 21 into a parameter indicating this range. , find the peak frequency value from the residual υ data. That is, the zero-order standard deviation calculating device 23, which calculates the peak value on the histogram formed by the image data of the organ part obtained by contrast agent injection, calculates the peak value calculated by the peak detecting device 22. The degree of clustering of image data frequencies centered around is determined as a standard deviation, and the determined standard deviation and the peak value are provided to the comparison/judgment device 24.

This comparison/judgment device 24 uses a pre-given optimal value (
(peak value of optimal density level frequency of contrast agent image)
The peak value outputted by the peak calculation device 22 and the standard deviation value outputted by the standard deviation calculation device 23 are compared based on a parameter indicating an appropriate standard deviation (standard deviation with respect to the optimal peak value). Determine whether it is a value.

In other words, if the values are appropriate, both the peak value and the standard deviation should be close to the value indicated by the parameter, and the peak value, standard deviation, or both should deviate from the value indicated by the parameter by more than a certain amount. If so, this means that it is not an appropriate value.

Therefore, after making such a determination, the comparison determination device 24 issues a command for image processing to the image processing device 14 if the comparison result is appropriate, and if the comparison result is inappropriate, the contrast agent injection device 16 is given an instruction to increase the amount of contrast agent. Give instructions.

As a result of the above, it can be determined whether the image data is of sufficient quality for image processing.

Although the above description has been made regarding the case where the process is implemented by hardware, the same thing can also be performed by software processing using a program, so it can also be replaced by software processing.

Further, the present invention is not limited to the embodiments described above and shown in the drawings, but can be implemented with appropriate modifications within the scope of the gist thereof. For example, in the above embodiments, the frequency of the gray level of image data Although we focused only on the image and applied feedback, it is also possible to control it by making judgments based on the results of image processing. That is, when extracting the outline of the heart or the like as part of image processing, if good data cannot be obtained, the amount of contrast agent may be increased and imaging may be performed again.

〔Effect of the invention〕

As described in detail above, the present invention injects a contrast agent into the circulatory system (ventricular) of a subject using a contrast agent injection device, and performs X-ray photography by exposing the subject to X-rays using an X-ray device. In a diagnostic device that converts an image captured by X-ray photography into image data using an image data converting means and processes this image data to obtain information necessary for diagnosis, the contrast agent injection device may predetermine a set injection amount. The set injection amount is set to a minimum amount, and when an increase instruction is received, the set injection amount is increased by a predetermined amount, and when an injection instruction is received, the contrast medium is injected by the set injection amount, and A means for determining from the image data whether the image data can be distinguished from other image data by a contrast agent, and if not, generating a command to increase the amount of contrast agent injection; and a means for detecting the state of cardiac motion from the biological signals of the subject. , means for generating the contrast medium injection command in synchronization with ventricular diastole and giving an imaging command to the X-ray device when the ventricle expands or contracts, and performs X-ray imaging in synchronization with cardiac motion. Contrast medium is injected, and the amount of contrast medium injected is kept to a minimum. From the image data obtained at this time, it is determined whether it is possible to distinguish between necessary data and unnecessary data. The system automatically adjusts the amount of contrast medium to be injected to the minimum amount necessary by issuing a command to increase the amount of contrast medium and checking the image data again, so there is no need to worry about injecting an unnecessary amount of contrast medium. Therefore, the burden on the subject during contrast medium injection is minimized, and the safety of life during injection is higher, and since contrast medium injection is performed during ventricular diastole,
In this respect as well, X-ray diagnosis has excellent features such as ensuring safety and reducing the burden on the subject, and since X-rays are taken when the ventricle is expanding and contracting, which is necessary for diagnosis, it is possible to take images without waste. equipment can be provided.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a block diagram showing the configuration of the image judgment device shown in Fig. 1, and Fig. 3 is an example of a density histogram of image data for one image. FIG. Image determination device, 16...Contrast medium injection device, 17...
Synchronization device, 2nd... Grayscale frequency calculation device, 22... Peak calculation device, 23... Standard deviation calculation device, 24...
・Comparison and judgment device.

Claims (2)

[Claims] (1) A contrast agent is injected into the ventricle of the subject using a contrast agent injection device, and an X-ray device is used to expose the subject to X-rays to perform X-ray photography. In a diagnostic device that converts a captured image into image data using an image data conversion means and processes this image data to obtain information necessary for diagnosis, the contrast agent injection device adjusts the set injection amount to a predetermined minimum. The set injection volume is increased by a predetermined amount when the injection volume is set and an increase command is received, and when the injection command is received, the contrast medium is injected for the set injection volume. A determination means that determines whether the contrast agent image data can be distinguished from other image data and, if not, generates a command to increase the amount of contrast agent injection; An X-ray diagnostic apparatus characterized by comprising means for generating the contrast medium injection command in synchronization with the above, and for giving an imaging command to the X-ray apparatus at the time of expansion or contraction of the ventricle. step (2) The judgment manual includes means for obtaining a histogram for each density level of image data, means for removing a region corresponding to the background image from this histogram, and means for obtaining a peak value of the histogram after this removal; The X-ray diagnostic apparatus according to claim 1, which has a beam centered on this peak value.