JPH0429383B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a radiological diagnostic apparatus that can display images useful for medical diagnosis by detecting radiation transmitted through a subject.

[Technical background of the invention and its problems]

Conventionally, as a radiological diagnostic device, for example, an X-ray diagnostic device, U.S. Pat.
There is a device disclosed in No. 4204226.

However, the X-ray diagnostic apparatus has the following problems.

First of all, with the X-ray diagnostic apparatus, it is possible to observe, for example, the flow of blood using moving images, but due to the heat capacity limitations of the X-ray tube, the amount of X-rays emitted to obtain one moving image is limited. is limited, and as a result, the density resolution of one image is reduced. Second, in frozen image photography using pulsed X-ray exposure, the amount of X-rays exposed per image is larger than when obtaining a video, so although it is possible to increase the density resolution of the image, Because the internal flow is not strictly considered, images with contrast agent concentrations near the maximum may be missed. As a result, the density resolution of one image is reduced. Third, when obtaining two types of images, a moving image and a frozen image, for the same subject, the two types of images are taken separately without being related to each other, so there is unnecessary exposure to X-rays. X-rays may be given to the specimen, or the timing of X-ray exposure may be incorrect, resulting in low-resolution images being obtained.

The above-mentioned problems also occur with X-ray diagnostic apparatuses that employ cine film photography or spot photography.

[Object of the Invention] The present invention has been made in view of the above circumstances, and it is possible to obtain functional diagnostic images with high temporal resolution while minimizing radiation exposure, and to perform high-quality morphological diagnosis based on the functional diagnostic images. It is an object of the present invention to provide a radiological diagnostic apparatus that can obtain images and has high diagnostic efficiency.

[Summary of the invention]

The outline of the present invention for achieving the above object includes a radiation generating device, an electrocardiogram measuring device, a contrast agent injection device,
In a radiation diagnostic apparatus including a radiation detection device and an image display device, a control signal for detecting an R wave in electrocardiographic data output from the electrocardiographic measuring device and controlling the operation timing of each device including the device. and a system controller that outputs a mask image before contrast agent injection and a contrast image after contrast agent injection obtained by continuous X-ray exposure based on control signals input from the system controller. Then, a subtraction image obtained by subtracting between both images is analyzed to create a functional diagram showing the functions of the circulatory system and measured values.Furthermore, based on the functional diagram and measured values, pulse An image processing device that stores a mask image before contrast agent injection and a contrast image after contrast agent injection obtained by radiation exposure, and performs subtraction between both images to obtain a subtraction image. It is characterized by:

[Embodiments of the invention]

An embodiment of the invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a radiological diagnostic apparatus, such as an X-ray diagnostic apparatus, which is an embodiment of the present invention.

In FIG. 1, the reference numeral 1 indicates an
A ray generating device is, for example, an X-ray tube, and 3 is an X-ray detecting device that detects an X-ray transmitted image obtained by passing through the subject 2 and converts it into an analog electrical signal. For example, it has at least an image intensifier that converts an X-ray transmission image into an optical image, an optical system that adjusts the light amount of the optical image, and an image pickup tube that converts the optical image into an analog electrical signal (video signal). configured. 4 indicates:
An A/D converter that converts an analog electrical signal output from the X-ray detection device 3 into a digital electrical signal, a functional inspection processing section 4A (described later), a morphology inspection processing section 4B (described later), and various image data. This is an image processing device that is equipped with a memory for storing information and performs inter-image and intra-image arithmetic processing. 5 is a D/A converter that converts the digital signal output from the image processing device 4 into an analog signal;
The image display device includes at least a display that displays the analog signal as an image. Reference numeral 6 designates an X-ray generation controller, which irradiates continuous X-rays when performing a functional test, and emits pulsed X-rays when performing a morphological test, in response to a trigger signal output from a system controller 9, which will be described later. The X-ray tube 1 is controlled so as to emit . Reference numeral 7 denotes an electrocardiogram measuring device with a built-in A/D converter that measures the electrocardiogram of the subject 2 and outputs the digital data to a system controller 9, which will be described later. Reference numeral 8 denotes a contrast agent injection device that injects a predetermined amount of angiographic contrast agent into the subject 2 at a predetermined time under the control of a system controller 9, which will be described later. 9 indicates the operation timing of each of the X-ray detection device 3, image processing device 4, image display device 5, X-ray generation controller 6, and contrast agent injection device 8 using a digital signal output from the electrocardiogram measuring device 7. It is a system controller that performs control based on data. 10 indicates the selection and designation of imaging conditions, imaging sequences, and image processing modes that are preprogrammed in the system controller 9 and that correspond to the diagnostic site and contrast agent injection position within the subject 2. It is a system console with a keyboard that can be used to

To explain the image processing device 4 in more detail, the functional test processing section 4A in the image processing device 4 includes:
A group of images captured by continuous X-ray exposure, for example, a group of images taken before the contrast agent is injected (mask image group) and a group of images taken after the contrast agent reaches the target area (contrast image group) A contrast agent concentration time change diagram showing changes in contrast agent concentration over time by generating a contrast image group (subtraction image group) and analyzing the generated subtraction image group;
Create functional diagrams and measured values that show the functions of the circulatory system, such as a heart volume time change diagram within one heartbeat that shows changes over time in heart volume within one heartbeat, and a heart contour time change diagram that shows changes in heart contour over time, The morphological inspection processing unit 4B is configured to store these, and from the mask image group and contrast image group captured by pulsed X-ray irradiation, a mask with the same pulse number as the contrast image with the highest contrast agent concentration is The functional test processing unit 4 is configured to select a subtraction image, generate a subtraction image, and store it.
Each of A and the form inspection processing section 4B is configured to start its operation in response to a processing start signal output from a system controller 9, which will be described later.

The system controller 9, as shown in FIG.
R wave detection means 9A that inputs electrocardiographic data and detects R waves in the electrocardiographic data;
The R-wave counting means 9B counts the number of R-waves detected by the R-wave counting means 9B.
A first trigger signal generating means 9C, which outputs a trigger signal instructing the X-ray generation controller 6 and the X-ray detecting device 3 to start and end their operations when the number reaches a preset value of 0, and an R-wave counting means. When the number of R waves counted at 9B reaches a number preset on the system console 10 with a keyboard, a second trigger signal is outputted to instruct the contrast agent injection device 8 to start and end the operation.
When the number of R waves counted by the trigger signal generating means 9D and the R wave counting means 9B reaches the number preset on the system console 10 with a keyboard, the image processing device 4 and the image display device 5 each Processing start signal generating means 9 for outputting a processing start signal instructing the start of a predetermined operation
E. Send a mode command signal to the X-ray generation controller 6 to specify either continuous X-ray exposure mode or pulsed X-ray exposure mode according to the X-ray exposure conditions entered on the system console 10 with keyboard. It is configured to have mode command signal output means 9F for outputting.

The system console 10 with keyboard includes:
Contrast concentration curves preset as standard for the combination of diagnostic site and contrast injection site, heartbeat number that determines the timing for acquiring images before the contrast agent is injected, and when the contrast agent reaches the predetermined site. The heartbeat number that determines the timing to collect images and the heartbeat number that determines the timing to inject contrast media are displayed on the monitor, and the various standard heartbeat numbers are displayed on the monitor through dialogue with the operator. It is also configured to be able to change the mode and enter either the functional test or the morphological test mode.

Next, the operation of the above configuration will be explained.

First, a functional test is performed.

The system console 10 with a keyboard displays a list of diagnostic sites and contrast medium injection sites as a menu on the monitor screen, and requests the operator to specify the diagnostic site and contrast medium injection site. The operator
When, for example, the heart is entered as the functional diagnosis site, the coronary artery is the morphological diagnosis site, and the brachiojugular vein as the contrast medium injection site through the keyboard, the system console 10 with the keyboard inputs the standard contrast medium settings for the input information. Concentration curves, heartbeat numbers that determine the timing for image acquisition, heartbeat numbers that determine the timing for injecting contrast media, etc. are displayed on the monitor, allowing the operator to decide whether these settings are appropriate for functional diagnosis. request. When the various setting values displayed on the monitor are inappropriate, the operator appropriately modifies the setting values displayed on the monitor via the keyboard. Through such interaction with the operator, various heartbeat numbers, which serve as the basis for the functional diagnosis mode and the timing settings required for functional diagnosis, are input from the system console 10 with a keyboard.

Next, the electrocardiogram measuring device 7 sequentially outputs the electrocardiographic data of the subject 2 to the system controller 9, and the system controller 9 displays the heart rate value and its fluctuations moment by moment on the system console 10 with a keyboard. Display it as a graph on the monitor screen. When the heart rate fluctuation becomes small, a request to start a functional test is displayed on the monitor screen on the system console 10 with a keyboard, and the operator inputs a request to start the test via the keyboard. Due to the input to start the function test, R in the system controller 9
The wave detection means 9A starts detecting R waves in the electrocardiogram data, and the R wave counting means 9B starts counting the number of R waves.

On the other hand, the system controller 9, which has input the functional diagnosis mode from the system console 10 with a keyboard, sends a mode command signal containing conditions for continuous X-ray exposure to the X-ray generation controller 6 from the mode command signal output section 9F. Output.

When the number of R waves counted by the R wave counting means 9B matches the first heart rate number K preset on the system console with keyboard 10,
As shown in FIG. 3, from the first trigger signal generation means 9C to the X-ray generation controller 6 and the X-ray detection device 3,
At the same time, a processing start signal is outputted from the processing start signal generating means 9E to the function test processing section 4A in the image processing device 4. When a trigger signal and a processing start signal synchronized with the first heartbeat number K are output, continuous X-rays are irradiated from the X-ray tube 1 to the subject 2 under the control of the X-ray generation controller 6. The X-rays that have passed through the specimen 2 are converted into a digital video signal by the X-ray detection device 3, and the video signal is output to the functional test processing section 4A in the image processing device 4. The image processing device 4 captures a large number of images of each phase based on the R wave based on the input video signal, and stores these as a plurality of images (mask images) before contrast agent injection. X-ray exposure and image capture are triggered by a trigger that is output when the number of R waves counted by the R wave counting means 9B matches a second heart rate number L preset in the system console with keyboard 10. The signal is first trigger signal generating means 9
This process continues until the output is output from C.

Next, the number of R waves counted by the R wave counting means 9B is determined by the number of R waves counted by the R wave counting means 9B.
When the heart rate matches the third heartbeat number O set in advance with 0, a trigger signal is output from the second trigger signal generating means 9D to the contrast agent injection device 8, as shown in FIG. A contrast medium is injected into the subject 2 by the contrast medium injection device 8 during a predetermined period.

After the contrast medium is injected, when the number of R waves counted by the R wave counting means 9B matches the fourth heartbeat number M preset on the system console with keyboard 10, as shown in FIG. A trigger signal is outputted from the trigger signal generation means 9D to the X-ray generation controller 6 and the X-ray detection device 3, and at the same time, a processing start signal is outputted from the processing start signal generation means 9E to the image processing device 4. The fourth heartbeat number M indicates the heartbeat determined clinically in advance until the contrast medium reaches the target site from the injection site of the contrast medium.
When the trigger signal and processing start signal synchronized with the fourth heartbeat number are output, the X-ray generation controller 6
Continuous X-rays from X-ray tube 1 to subject 2 are controlled by
The X-rays transmitted through the subject 2 are converted into digital video signals by the X-ray detection device 3, and the video signals are output to the image processing device 4. The image processing device 4 captures a large number of images of each phase based on the R wave based on the input video signal, and stores these as a plurality of images (contrast images) after the contrast agent reaches a predetermined region. Furthermore, in response to the processing start signal, the image processing device 4 selects a mask image having the same phase as a large number of contrast images of each phase based on the R wave from among the mask image group, and then selects a contrast image from the mask image. By subtracting the image,
Generate a subtraction image with the background removed,
After the subtraction images are once stored, the subtraction images are outputted to the image display device 5 either continuously or at predetermined intervals. The image display device 5 displays the subtraction image as a functional diagnosis image.

Next, the functional test processing section 4A creates a functional diagram and measured values according to the following procedure. First, on the subtraction image displayed on the image display device 5, a region where the temporal change of the contrast agent is desired is marked.
Set ROI. In the subtraction image
For the ROI setting portion, image density is extracted for each heartbeat cycle, and a graph showing the image density for each heartbeat over time is displayed on the image display device 5 as a contrast agent concentration time change chart. Data regarding image density that changes over time is stored in a memory (not shown) because it is necessary to determine the timing of X-ray exposure and image acquisition when performing morphological diagnosis, which will be described later. Then,
Based on the displayed contrast agent time change diagram, time filtering is applied to the subtraction image for one heartbeat in which the contrast agent concentration of the ROI indicating the region where the function is to be determined, such as the left ventricle of the heart, is close to the maximum, and then the subtraction image for one heartbeat is obtained. Create a subtraction image for functional analysis. The created subtraction image for functional analysis for one heartbeat is Fourier transformed to obtain the amplitude and phase for each pixel, and an amplitude image and a phase image are created, stored, and displayed. Then, by detecting pixels that match a predetermined pixel density value from the functional analysis subtraction image for one heartbeat, which has obtained the amplitude image and phase image, a heart contour image is created with the detected pixels as an outline. is created for one heartbeat cycle. From the created heart contour image, a heart volume time change diagram for one heartbeat is created by integrating the density values within the area surrounded by the contour. Functional measurements such as edge expulsion, contraction and expansion of the myocardium are performed from the created heart volume time change diagram, and the functional diagram and measured values are displayed on the image display device 5.

Next, a morphological examination is performed based on the contrast agent concentration time change diagram obtained in the functional examination.

First, when the contrast agent concentration time change chart obtained in the functional test is displayed on the image display device 5, the operator uses the system console 10 with a keyboard to select the X-rays necessary for carrying out the morphological test. Enter the heartbeat number that specifies the exposure period and the heartbeat number that specifies the start of contrast medium injection. The mode command signal output means 9F in the system controller 9 stores the heartbeat number and sets the period designated by the heartbeat number as the X-ray generation period and the contrast medium injection period.

Next, the electrocardiogram measuring device 7 sequentially outputs the electrocardiographic data of the subject 2 to the system controller 9, and the system controller 9 displays the heart rate value and its fluctuations moment by moment on the system console 10 with a keyboard. Display on the monitor screen. When the fluctuation in heart rate becomes small, the pulse width of pulsed X-ray irradiation, the delay time from the R wave, and the pulse repetition time are input into the system controller 9 from the system console 10 with a keyboard. The mode command signal output means 9F in the system controller 9 calculates the maximum number of pulses within a heartbeat based on the inputted time and average heart rate, and displays this maximum number of pulses on the monitor screen of the system console 10 with a keyboard. let Based on the display on the monitor screen, the operator selects an appropriate number of pulses, for example two, which is less than or equal to the maximum number of pulses, and inputs this.

After inputting the number of two pulses, when a test start command is input via the system console 10 with a keyboard, the R wave counting means 9B starts counting the number of R waves, similarly to the above functional test.

When the number of R waves counted by the R wave counting means 9B matches the first heart rate number K preset on the system console with keyboard 10,
A trigger signal output from the first trigger signal generation means 9C is input to the X-ray generation controller 6, and a mode signal for commanding pulsed X-ray exposure from the mode command signal output means 9F in synchronization with the trigger signal. enters. At the same time, a trigger signal is outputted from the first trigger signal generation means 9C to the X-ray detection device 3, and a processing start signal is outputted from the processing start signal generation means 9E to the morphology inspection processing section 4B in the image processing device 4. Ru. Then, as shown in FIG. 4, from the X-ray tube 1 under the control of the X-ray generation controller 6, within the X-ray generation period _T1 after the R wave, T Pulse interval from ₂
For example, two pulsed X-rays of T ₃ are emitted per heartbeat. The pulsed X-ray irradiation is performed using a trigger signal that is output when the number of R waves counted by the R wave counting means 9B matches the second heart rate number L preset in the system console with keyboard 10. This is done until the period T ₁ has elapsed. On the other hand, the morphology inspection processing unit 4B in the image processing device 4 captures images for each pulsed X-ray exposure and stores them as a plurality of images (mask images) before contrast agent injection.

Next, as in the case of the functional test, the contrast medium injection device 8 is operated in synchronization with the third heartbeat number, and the contrast medium is injected into the subject 2.

After injecting the contrast agent, in the same manner as when capturing the mask image, a large number of contrast images are obtained by irradiating pulsed X-rays based on the fourth heartbeat number M and the fifth heartbeat number N. The image is stored in the memory within the morphology inspection processing section 4B. Then, the morphological examination processing unit 4B generates a subtraction image from the contrast image and the mask image, and the generated subtraction image is displayed on the image display device 5 as an image for morphological diagnosis.

Although one embodiment of the present invention has been described in detail above, the present invention is not limited to the above embodiment, and can be implemented with appropriate modifications within the scope of the gist of the invention. Needless to say.

In the embodiment described above, the morphology inspection is performed only once, but the morphology inspection may be performed two or more times. Furthermore, the time interval between the functional test and the morphological test may be arbitrary.

〔Effect of the invention〕

As described in detail above, according to the present invention, the R waves of the subject outputted from the electrocardiogram measuring device are counted, and the predetermined R waves input interactively via the system console with a keyboard and the counted R waves are counted. The trigger signal and processing start signal output from the system controller when the It is possible to reduce unnecessary radiation exposure to the subject, and it is possible to display high-quality images. Moreover, since we perform functional tests and perform morphological tests based on the obtained data such as functional diagrams, we can minimize radiation exposure from this point of view as well. It is possible to provide functional diagnostic images and functional measurement values with high temporal resolution, and high-quality morphological diagnostic images. Therefore, accurate medical diagnosis can be performed using the radiological diagnostic apparatus according to the present invention.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing a system controller in the embodiment, and FIGS. 3 and 4 are timing diagrams for explaining the operation of the embodiment. It's a chat. 1...X-ray generator, 3...X-ray detector, 4
...Image processing device, 5...Image display device, 7...
Electrocardiogram measuring device, 8...Contrast medium injection device, 9...System controller.

Claims (1)

[Claims] 1. In a radiation diagnostic device equipped with a radiation generator, an electrocardiogram measuring device, a contrast agent injection device, a radiation detecting device, and an image display device, detect R waves in electrocardiographic data output from the electrocardiographic measuring device. a system controller that outputs a control signal to control the operation timing of each device including the device; and a system controller that outputs a control signal to control the operation timing of each device including the device; The mask image before injection and the contrast image after contrast agent injection are stored, and the subtraction image obtained by subtracting between the two images is analyzed to create a functional diagram and measurement values showing the functions of the circulatory system. Furthermore, based on the functional diagram and the measured values, a mask image before contrast agent injection and a contrast image after contrast agent injection obtained by pulsed X-ray irradiation are stored, and subtraction is performed between the two images. What is claimed is: 1. A radiological diagnostic apparatus comprising: an image processing device for obtaining a subtraction image.