JPS6050900A - X-ray diagnostic apparatus - Google Patents

Abstract

PURPOSE:To realize drawing of coronary artery by starting radiation of x-ray after the specified time from the QRS timing of an electrocardiogram signal detected by an R wave detecting apparatus and by stopping radiation of X-ray at the timing of front edge of the next QRS wave. CONSTITUTION:The R wave timing pulse obtained by an R wave detecting apparatus 8 is input to a timing control apparatus 9 and becomes a pulse train of Fig. c. A radiation control signal is generated from this pulse train and a picture -taking command signal obtained by operation of the radiation start switch 10 from an external circuit. This control signal controls an X-ray controller 3 and thereby the X-ray is radiated during the time range X shown in Fig. e. Namely, radiation of X-ray is started in the vicinity of initial expansion of the heart and is stopped at the initial timing (R wave detection timing) of contraction. This cycle is repeated for each pulse, and after the predetermined time (or number of pulses), repeated radiation of X-ray is stopped when the X-ray picture taking command signal disappears.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an xsit diagnostic device, and more particularly to an X-ray diagnostic device for circulatory organs that makes it possible to depict coronary arteries without using a catheter.

[Technical Background of the Invention II] If a coronary artery, which is a blood vessel that feeds the heart, is occluded, it will cause a myocardial infarction, so it is particularly important to confirm whether it is normal or abnormal. Coronary angiography, which involves injecting a drug and performing XS+II, has become popular. However, catheterization, which involves inserting a tube directly into an arterial blood vessel, is dangerous and requires highly skilled and highly skilled medical techniques, placing an enormous physical and mental burden on the patient and doctor.

On the other hand, in recent years, intravenous subtraction angiography (Ven) is used to image renal arteries and carotid arteries by injecting a contrast medium through a vein and subtracting (taking the difference) the X-ray images before and after the contrast medium injection. -ous s ubtrac
t+on A noiooraphy ~hereinafter referred to as “vSA
A law has been developed called ``. However, since the heart is constantly in motion, it has been almost impossible to depict coronary arteries using this vSA method.

Furthermore, in the vSA method, it is conceivable to emit X-rays continuously and operate the fluoroscopic image capture means in synchronization with the heart's movement timing, but in this case, the fluoroscopic image In order to obtain sufficient X-ray output to maintain Con1 Helast in good condition, XI! The capacity of the tube must be increased, resulting in a larger device and 21 store tubes. Furthermore, in this case, there is also the problem that the X-ray exposure of the subject to be examined is increased.

[Object of the Invention] An object of the present invention is to provide an X-ray diagnostic apparatus that enables depiction of coronary arteries using the VSA method.

[Summary of Defense] The present invention is designed to detect X-rays generated by an X-ray generator and transmitted through a subject using a detection device to obtain image information for diagnosis. The timing of the QR8 wave of the electrocardiogram signal detected from is detected by the R wave detection device, and based on this detection, the timing control device controls the X-ray generator to generate X $1 after a predetermined time of the timing of the QR8 wave.
Start flit radiation and start the leading edge of the next QR8 wave (
It is characterized by stopping the X-ray exposure at the timing of the normal start-up.

[Embodiments of the invention] FIG. 1 shows the configuration of an embodiment of the present invention.

A subject (generally a human body) H placed on a bed top 1 includes an X-ray tube 2 and an X-ray power source that drives it.
An X-ray generator including a ray controller 3 irradiates X-rays. Xl transmitted through the heart part of the subject H and the bed top 1! For example, an X-ray image intensifier,
The image is detected as a plane image by an X-ray image detection device 4, such as an X-ray television 1m system consisting of a television camera and an optical system, and its output is input to a data processing device 5 as an electrical signal.

On the other hand, an electrocardiogram electrode 6 (actually connected to the limbs, but only the one connected to the wrist is shown in the figure) is connected to the subject H, and an electrocardiogram signal is obtained by an electrocardiograph 7. The obtained electrocardiogram signal is given to the R wave detection device 8, which detects the QR8 wave of the electrocardiogram waveform, that is, the timing of the R wave, and based on the timing of this R wave, the timing control is performed. ! i at position 9
A @copper ti control signal is generated that controls the timing of line generation. In response to this exposure control signal,
is controlled to irradiate the subject 1-1 with X-rays and control the X-ray irradiation time.

FIG. 2 is a timing pulse chart for explaining in detail the timing relationship of this combination of controls.

FIG. 12(a) shows an example of an electrocardiogram waveform of a standard second limb lead obtained from a subject H, for example. Each part of the electrocardiogram waveform is P and Q as shown.

They are called by the symbols R, S, and T, and the QR8 portion represents the point at which the heart begins to contract. Usually, this guidance method is most suitable for timing detection because the R wave 1j is a spike-like wave with a large amplitude. FIG. 2(b) is a timing pulse waveform of the start of cardiac contraction obtained by the R-wave detection device 8 using the rise of the R wave of the electrocardiogram signal shown in FIG. 2(a). The technology for obtaining this timing pulse has already been established.

By the way, the coronary arteries can best be depicted during the end-diastole phase of the heart, not during the systole phase. In other words, during systole, blood is ejected from the heart to the aorta, but because the myocardium is contracting, there is little blood in the coronary arteries, which is difficult to depict, whereas during diastole, when the myocardium is relaxed, blood is ejected from the aorta to the coronary arteries. Blood flows into the coronary arteries, increasing the volume of blood in the coronary arteries. Moreover,
During end-diastole, the period between the end of diastole and the beginning of the next contraction, the heart moves the least during the cardiac cycle. Therefore, at the end of diastole
Obtaining a line image provides the best (clear and accurate) depiction of the coronary arteries. However, directly detecting end-diastolic timing from the electrocardiogram signal is an inconvenience.

Figure 2 (C') shows the predetermined time in seconds (seconds) from the R wave timing.
For example, it is a waveform of a pulse train having a width of 0.5 seconds), and FIG. 2(d) shows the waveform of the XI! This is the waveform of the II shadow command signal. Figure 2(e) shows the XI! of Figure 2(d)! From the shooting start (START) of the shooting command signal to the shooting end (STOP>) From the trailing edge (falling) of each pulse of the pulse train in the same figure (C) to the leading edge 6- (rising 1 nil) of the next pulse The exposure control 111g is made up of a pulse train generated with a pulse width of , and X-rays are irradiated at the timing of this pulse.

At the same time, the R-wave timing pulse obtained by the R-wave detection device 8 is input to the timing control device 9, and as shown in Fig. 2 (C
), an exposure control signal is generated between this pulse train and an imaging command signal from the external operation of the autopsy start switch 10, and this signal controls the X-ray roller 3. X-rays are irradiated during the time range X shown in Figure (e). In other words, near the early stage of heart expansion,
The ray irradiation is started and the irradiation is stopped at the beginning of contraction (R wave detection timing). Repeat this for each heartbeat for 1 hour in advance.
After a certain time (or heart rate), the XwA imaging command signal disappears and the repetition of X-ray irradiation stops (see Figure 2 (after 5TOP in (1)). Generally, the interval between waves is 0.
It is about 5 seconds to 1.2 seconds, and there are individual differences and it is not necessarily constant even for the same person, so the predetermined time period shown in Fig. 2 (C)'c is usually 0% of the average value of the R wave interval. It may be set to about 80%.

Since the R-wave interval usually follows the immediately preceding R-wave interval, it is also possible to estimate the next R-wave interval from changes in the R-wave interval over the previous several heartbeats and set the predetermined time t.

In actual X-ray imaging, a contrast agent is injected into the subject H through a vein, and before or immediately after that, an imaging command is given using the X-ray @ 11 start switch 10, and the X-ray is transmitted using an exposure pulse as shown in Figure 2(e). The irradiation is repeated and the X-ray image obtained by the X-ray image detection device 4 is taken into the data processing device 5. The data processing device 5 converts the video signal of the X-ray image into an A/D (analog)
(digital) and stored in digital memory. The contrast agent mixed with blood flows along the route of vein → vena cava → right atrium → right ventricle → pulmonary artery → lung → pulmonary vein → left atrium → left ventricle, and if it has not yet reached the coronary artery, it depicts the coronary artery. Since this is the background image used for this purpose, this will be used as the mask image. The contrast medium then flows into the coronary artery, and after several heartbeats, when the contrast medium disappears from the blood in the left ventricle, the contrast medium also stops flowing into the coronary artery.

At this point, the X-ray irradiation is finished. The image data stored in the digital memory is a contrast image at the time when the contrast agent was injected into the coronary artery and a mask image without the contrast agent being injected.If processing such as subtraction between these two images is performed, the coronary artery image becomes clearer. is depicted in The finally obtained image is displayed on the display 11 and, if necessary, is saved as a file in an image file device 12 using a magnetic disk, an optical disk, etc.

In the VSA method, the contrast agent is mixed with +fit W&, resulting in a thin contrast agent concentration, and it is necessary to increase the amount of X-ray radiation to obtain an image with good S,/N (signal-to-noise ratio). Since X-rays are irradiated only during the time when coronary artery blood is flowing in, unnecessary X-ray irradiation to the subject is prevented. −
can be kept to the minimum necessary.

Furthermore, in the case of the same X-ray tube capacity, if the pulse irradiation of the embodiment is performed, stronger X-ray irradiation for only the necessary time width is possible.
The contrast of line images can be increased accordingly.

Furthermore, as mentioned earlier, the timing of X-ray irradiation according to this embodiment, that is, the extended early morning, corresponds to the time phase when the movement of the heart is least. Another advantage is that it can be minimized.

In this way, XII images with a good S/interval can be obtained by irradiating sufficiently strong X-rays only in the necessary time region, that is, the end diastole, without irradiating the subject H with X-rays in unnecessary time regions. xi of the cardiac phase with the least movement.
A crown that was previously impossible because s can be obtained! l] It becomes possible to depict the pulse using VSA.

It should be noted that the present invention is not limited to the embodiments described above and shown in the drawings, but can be implemented with various modifications without changing the gist thereof.

For example, in the above embodiment, a case was explained in which an image of a coronary artery was obtained using the VSA method, but this method can be used to obtain an It is also effective to apply the invention.

In addition, this defense is valid not only for the VSA method but also for other X-ray photography, such as film photography, as long as it targets the heart and its surroundings.

[Effects of the Invention 1] According to the present invention, an X-ray diagnostic device is provided which is capable of depicting coronary arteries using the VSA method, which has been difficult to image in the past, and which can realize convenient X-ray imaging of the heart and its surroundings. can offer blasphemy.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram showing a schematic configuration of an embodiment of the present invention, and FIG. 2 is a timing chart for explaining the embodiment. DESCRIPTION OF SYMBOLS 1... Bed top plate, 2... X-ray tube, 3... X-ray controller, 4... X-ray image detection device, 5... Data processing device, 6... Electrocardiogram electrode, 7 ...electrocardiograph, 8.
...R wave detection device, 9...timing control device, 10
... Exposure start switch, 11... Display, 1
2... Image file device. Applicant's agent Patent attorney Takehiko Suzue 11- Figure 1

Claims (1)

[Claims] An X-ray generator, a detection device that detects the X-rays generated by the X-ray generator and transmitted through the subject, an electrocardiogram signal detection device that detects the electrocardiogram signal of the subject, and an electrocardiogram signal detected by the electrocardiogram signal detection device. An R wave detection device that detects the timing of the QR8 wave of an electrocardiogram signal, and a Q wave detection device that detects the timing of the QR8 wave of an electrocardiogram signal.
The X-ray generator is set to 1lilJI in order to start X1llll after opening at a predetermined time of the timing of the R8 wave and stop the X11 exposure at the timing of the leading edge of the next QR8 wave.
1. An X-ray diagnostic apparatus comprising a timing control device according to item II, and providing image information based on detection by the detection device for diagnosis.