JP2010005480A - X-ray diagnostic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an X-ray diagnostic apparatus which can carry out contrast agent injection control optimum for acquiring 3-dimensional reconstruction data and image pick-up motion control. <P>SOLUTION: The X-ray diagnostic apparatus capable of picking up a 3-dimensional contrast image of blood vessel of a subject includes: a contrast agent kinetics measurement means 21 capable of measuring a contrast agent injection starting time, a time the contrast agent reaching a target area on the image, and a time the contrast agent finishing to flow out based on a preliminarily taken contrast image or fluoroscopic image of the subject; a calculation means to calculate an X-ray exposure starting time, X-ray exposure finishing time, injection amount of the contrast agent, injection starting time, injection finishing time and injection velocity by a predetermined calculation process, based on the calculation result by the contrast agent kinetics measurement means 21; and a motion control means 1 to control an image pick-up timing and an injector motion based on the calculation result by the calculation means. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The X-ray diagnostic apparatus of the present invention relates to contrast agent injection control and imaging operation control for obtaining three-dimensional reconstruction data.

Rotational DSA imaging in a conventional X-ray diagnostic apparatus is performed according to the procedure shown in FIG.

In conventional rotational DSA imaging, a method is employed in which the time for the contrast medium to reach the target region ROI (Region Of Interest) after the start of contrast medium injection is obtained by preliminary fluoroscopy or preliminary imaging. In this method, the contrast medium is injected once under preliminary fluoroscopy or preliminary imaging before rotating DSA imaging, and the operator measures the time with a watch while watching the image, or the X-ray exposure timing based on experience-based considerations. The contrast medium injection amount and injection speed are determined.

Then, the data is input to the imaging protocol of the X-ray diagnostic apparatus, and the start and stop of imaging are automatically performed. Also, when the contrast agent injector and the system are linked, the start and end of the contrast agent injection of the injector are also controlled. However, no control means is provided for the contrast agent injection amount and injection rate. The X-ray generation timing is D
When the system starts the SA shooting sequence, no manual control means is provided.

Japanese Patent Application No. 10-127621

  The configuration of the above-described conventional X-ray diagnostic apparatus has the following problems.

Since the blood flow velocity changes depending on individual differences among patients, the target site, and the passage of time, it is difficult to understand by a conventional method that determines the inflow velocity of the contrast medium.

In addition, there is a case where the contrast agent is not injected into a desired blood vessel region due to a slight difference between the injection of the contrast agent and the imaging start timing, which causes an artifact when reconstructed three-dimensionally.

  Further, since the arm rotates at high speed, high rigidity and high driving force are required.

In addition, in the current apparatus, once entering the sequence controlled by the system at the time of rotating DSA shooting, it is not possible to start the shooting at the position desired by the operator because it is not possible to instruct manual switching from fluoroscopy to shooting. Data collection doesn't go well.

Further, since the optimum conditions for the injection amount and speed of the contrast agent are not known, the result is that the contrast agent is injected longer and more frequently, and the degree of invasiveness to the patient tends to increase.

In order to solve the above-described problems, in the present invention, an X-ray diagnostic apparatus capable of capturing a three-dimensional contrast image of a blood vessel of a subject is contrasted based on a contrast image or a fluoroscopic image of the subject that has been captured in advance. A contrast agent kinetic measurement unit capable of measuring a contrast agent start time, a time when the contrast agent reaches the target region on the image, and a time when the contrast agent has flowed out, and X based on the result of the contrast agent kinetic measurement unit Based on the calculation result obtained by the predetermined calculation processing, the calculation means for determining the irradiation start time, the X-ray exposure end time, the contrast agent injection amount, the injection start time, the injection end time, and the injection speed. An X-ray diagnostic apparatus comprising: an operation control unit that controls imaging timing and injector operation.

According to the X-ray diagnostic apparatus according to the present invention described above, the optimum X-ray exposure timing, contrast agent injection start time, contrast agent injection amount, and contrast image are respectively obtained during rotational DSA imaging for obtaining three-dimensional reconstruction data. The agent injection rate can be obtained, the exposure reduction by X-ray exposure and the invasiveness to the subject by the contrast agent can be reduced, and the contrast agent is injected into the blood vessel of interest in the entire frame of the rotating DSA data. It is possible to provide an X-ray diagnostic apparatus that can prevent occurrence of artifacts when three-dimensional reconstruction is performed by obtaining existing data and can improve the image quality of a three-dimensional reconstruction image.

The functional block diagram in embodiment of this invention is shown. The functional block diagram in embodiment of this invention is shown. An example of the angiographic X-ray image which concerns on embodiment of this invention is shown. An example of the manual photographing SW according to the embodiment of the present invention is shown. Another example of the manual photographing SW according to the embodiment of the present invention is shown. The functional block diagram for demonstrating the flow of a functional process which concerns on embodiment of this invention is shown. The figure for demonstrating the flow of the contrast agent which concerns on embodiment of this invention is shown. FIG. 2 is a schematic diagram for explaining a DSA imaging sequence according to an embodiment of the present invention. Another example of the manual photographing SW according to the embodiment of the present invention is shown. The figure for demonstrating the rotation DSA imaging | photography by a prior art is shown.

1 and 2 show functional block diagrams in the embodiment of the present invention.

With reference to the functional block diagrams shown in FIGS. 1 and 2, first, an ROI is designated on an image. For example, a pointing device 2 such as a mouse can be used to specify a region to be specified by enclosing the region to be specified with a circle or a polygon on the image display unit 3. The designated area may be a point, but it takes a certain amount of time (1, 2 seconds) for the X-ray system to switch from the fluoroscopic X-ray condition to the radiographic X-ray condition. It is more preferable to specify the area to have.

This ROI is displayed on the display unit 18 until the entire rotation DSA imaging sequence is completed, but is not configured to be recorded as image data actually collected by the image data collection unit 19. At the same time, as conditions for rotational DSA imaging, for example, voltage and current values, arm rotation start / end positions, contrast agent injection conditions, that is, injection amount, injection speed, etc. are transmitted to the fluoroscopic imaging sequence and the system controller 1. Input from the input section.

Through this system control unit 1, the tube control unit 4, the GAIN control unit, the ROI setting / pixel value control unit 6, the arm control unit 7, the injector control unit 8, the aperture control unit 9, and the photographing instruction display control unit are controlled. Further, the system control unit 1 can feed back information from each control unit and can control each control unit.

When the above-described preparation is completed, when the star control instruction of the DSA imaging sequence is given from the imaging SW to the system control unit 1, the aperture control unit 9 automatically X-rays up to the point where the ROI is first designated. The area is narrowed down so that X-rays are irradiated only to the portions necessary for photographing with the diaphragm 12. Here, the X-ray diaphragm 12 is applied only in a direction perpendicular to the arm rotation axis. This is because, if the direction parallel to the rotation axis is narrowed down, information is interrupted depending on the shooting angle. Then, a signal for performing mask image shooting is issued from the system control unit 1 to each control unit, and mask image shooting is performed. When the arm 13 has moved to the set angle, a signal is sent to the system control unit 1, and the system control unit 1 issues a signal that informs each control unit of the completion of mask image capturing, and mask image capturing ends. At the same time, the arm 13 returns to the rotation start position. When returning to the rotation start position, the arm control unit 7 issues a signal notifying the system control unit 1 that it has returned to the rotation start position, and the system control unit 1 issues a signal for performing fluoroscopy to each control unit. The fluoroscopy is started. At the same time, an injection start signal is transmitted to the injector control unit 8 to start injection of contrast medium from the injector 14.

The system controller 1 also automatically changes the gain detected from the detector 15 via the data detector 20 according to the fluoroscopic condition and feeds it back to the gain controller 5. At this time, arm rotation and shooting have not yet started. Here, as shown in FIG. 3, the X-ray system monitors the pixel density of the designated ROI by the ROI setting / pixel value control unit 6. At this time, the density change of a specific pixel in the ROI may be observed, or the average density of an arbitrary number of pixels in the ROI pixels may be viewed.

When the contrast agent injection is started and the ROI setting position on the fluoroscopic image is reached and the concentration in the ROI becomes equal to or higher than the predetermined value, the ROI setting / concentration value control unit controls the system control unit 1 with the specified value. The system control unit 1 switches from the fluoroscopic X-ray condition to the imaging X-ray condition. At this time, the system control unit 1 outputs a signal to the gain control unit 5 so that the detection gain on the detector 15 side is also switched for photographing. When each condition is completely switched, the system control unit 1 outputs a signal to each control unit so as to automatically start capturing a contrast image (arm rotation / photographing). When the arm 13 reaches the rotation end angle,
The arm control unit 7 issues a signal notifying the system control unit 1 that the rotation has been completed, and the system control unit 1 issues a signal notifying each control unit that the contrast image shooting has been completed.

Here, the system control unit 1 may output a signal to the injector control unit 8 in order to stop the injection of the contrast medium in the injector 14 at the same time as or after the contrast image capturing is completed. With the signal from the system control unit 1, the detector 15 causes the gain control unit 5 to turn off the detection gain at the same time as the contrast image capturing is completed.

Further, at the time of fluoroscopy, when the pixel density in the ROI range becomes equal to or higher than a predetermined value, the ROI setting / density value control unit can shoot the shooting instruction display control unit via the system control unit 1. A message indicating that contrast image capturing can be automatically started is displayed on the image display unit or any other location, and the operator can manually start contrast image capturing using the photographing SW 11. Also good.

FIGS. 4 to 5 show an example of manual photographing SW 11 that can be manually photographed.

The manual photographing SW 11 in FIG. 2 used by the operator shown in FIGS. 4 to 5 is configured to be switched in three stages. The first stage is ReadySW for starting anode rotation of the X-ray tube 16 in FIG. 2, the second stage is SW for starting mask image capturing, and the third stage is SW for starting contrast image capturing. At the time of mask image photographing, photographing is started by pressing both the first and second steps, mask image photographing is finished, and X-ray exposure is interrupted. After that, when the arm 13 is completely moved to the contrast image capturing start position, X-ray fluoroscopy is automatically started. The detection gain of the detector 15 is automatically switched. At this time, the operator waits while pressing the first and second steps, and when the shooting start message is displayed, pressing the third step SW starts contrast image shooting. Also good. The detection gain of the simultaneous detector 15 is also automatically switched for photographing. Further, only the contrast image shooting start button may be provided at another position.

In addition, the contrast image shooting start button is provided with a mechanical locking error prevention portion, and R
When the density value in the OI reaches a certain value, the system control unit 1 sends a lock release signal to the photographing SW1.
1 may be released for the first time by releasing the lock. 4 to 5 show an example of a hand switch.
It may be installed in another operation system panel of the control system provided in the line diagnosis device.

Further, the contrast image photographing SW11 may be provided at a place different from the Ready / mask image photographing SW11. While the Ready SW and the mask image capturing SW 11 are pressed at the same time, the contrast image capturing SW 11 is pressed. Furthermore, the contrast SW lock SW may be provided at a separate location, and the mechanism may be configured such that the third-stage SW in FIG. 4 cannot be pressed unless it is pressed. For example, this can be realized by providing a contrast SW lock SW as shown in FIG.

In addition, when the system control unit 1 has both a method for automatically instructing the start of contrast image capturing and a method for manually instructing contrast image capturing by an operator, when either one of the image capturing start instructions is generated The shooting may be started at, or the shooting may be started for the first time when two shooting start instructions are generated.

Next, the system determines the imaging start / end timing, injector contrast agent injection start / end timing, and the optimal amount of contrast medium using the previously captured image information, and automatically rotates D
An example of performing SA shooting will be described.

First, contrast imaging is performed to confirm blood vessel travel in a region where data is to be collected (pre-imaging). At this time, the contrast agent amount / time measuring unit 21 records the time when the injector 14 starts injecting the contrast agent and the time change of the injected contrast agent amount. The inflow speed and amount of the contrast agent may be arbitrary, but contrast is performed so that the entire blood vessel region is imaged.

Next, using the contrast-enhanced image, the point at which the contrast agent is injected first (the most upstream) and the point at which the contrast agent reaches the end of the entire blood vessel for the purpose of collecting rotational DSA data for three-dimensional reconstruction (Most downstream) is designated on the image using the pointing device 2.

The time when the injector 14 starts injecting the contrast agent is T1, the time T2 when the contrast agent appears in the image, and the time when the contrast agent reaches the most downstream point is T3. Here, the total amount of contrast medium flowing in each time of the injector 14 is V2 at the time T2, and V3 at the time T3.
Further, the speed at which the arm 13 rotates when taking a contrast image is set to Sdeg. /
sec and the rotation angle necessary for the rotational DSA image for 3D reconstruction is Ddeg. And

Reference is now made to FIG. FIG. 7 shows a view for explaining the relationship between the target blood vessel as ROI and the arrival time from T2 to T3 as the contrast agent is injected. It also calculates the contrast image capture start timing, required contrast agent amount, and capture end timing, and the system automatically
FIG. 8 shows a flow for controlling the A shooting sequence.

Referring to FIGS. 7 to 8, first, T1, T2, T3, V2, and V3 can be obtained from pre-shooting. The measurement is performed by the contrast medium amount / time measuring unit 21. S and D are also uniquely determined from the imaging protocol. From these conditions, the optimal amount of contrast agent for filling the blood vessel region with the contrast agent is calculated in all the angle data at the start of imaging (X-ray exposure), end timing, and imaging.

(1) X-ray imaging start timing This is when T3 time has elapsed since the injector 14 was turned on. Actually, it takes about 1 second for the X-ray condition to change from the fluoroscopic condition to the imaging condition. The shooting mode is entered at -1 (sec). At this time, not only the tube condition but also the detection gain of the detector 15 is simultaneously switched for photographing.

(2) Optimum amount of contrast agent-Rotational speed of arm 13: S (deg / sec)
Contrast (mask) image shooting angle: D (deg)
Time required for shooting: D / S (sec)
-Total amount of contrast medium when T2 has elapsed since the injector 14 was turned on: V2
-Total amount of contrast medium when T2 has elapsed since the injector 14 was turned on: V3
From the above, it takes T = D / S (sec) to complete the contrast image capturing.
.

Furthermore, the total amount V of the contrast agent for always filling the target blood vessel with the contrast agent during the D / S time is:
V = V3 + [β × (T + α)]
V3: Contrast medium amount required before imaging starts β = (V3-V2) / (T3-T2): Amount of contrast medium per unit time flowing between the most upstream point and the most downstream point (volume / sec) )
T = D / S (sec),
α: Arbitrary increase time. Time that the operator can set in advance for safety.

Here, α is a constant value that can be preset in the system based on the experience of the operator. The inflow speed of the contrast agent is the same as that during pre-imaging.

  (3) Shooting end timing The time point when the rotation of the arm 13 is ended.

With the above method, the contrast image capturing start timing, the necessary contrast medium amount, and the contrast image capturing end timing are calculated by the system control unit 1, and each (X-ray tube / detector 15 / arm 13 is calculated.
Etc.) The control unit is fed back to automatically control the rotating DSA sequence.

Next, FIG. 6 shows a functional block diagram for explaining a functional processing flow according to the embodiment of the present invention.

First, pre-imaging for determining imaging conditions and contrast medium conditions is performed. Imaging is performed from one direction while injecting a contrast medium at an arbitrary injection speed. The captured image is recorded in the image data collection unit. Then, using the photographed image, the ROI is designated on the image. The designation method can be designated by surrounding a desired area on the image display unit 3 with a circle or a polygon using a pointing device 2 such as a mouse.

The designated area may be a point, but the X-ray system has a certain amount of time (1, 2 seconds) for switching from the fluoroscopic X-ray condition to the radiographic X-ray condition. It is better to specify the area you have. On the image, two points are designated: the ROI at the point where the contrast medium of the target blood vessel is first injected (the most upstream point) and the ROI at which the contrast medium reaches the end (the most downstream point). Both of these ROIs are displayed on the monitor until the rotation DSA imaging sequence is completed, but are not recorded as actually collected image data. RO
When the designation of I is completed, the captured image is reproduced again. At this time, the system control unit 1
The above-described calculation is performed by exchanging time and density value information with the I setting / density value control and contrast agent amount / time measuring unit 21.

When the calculation is completed, the calculation result can be displayed at an arbitrary position on the image display unit 3.
At the end of the calculation, the operator sets the conditions for rotational DSA imaging, for example, the voltage and current values, the arm rotation start position / end position, the contrast agent injection conditions, that is, the injection amount, injection speed, etc. The information is input to the system control unit 1 (hereinafter, system control unit 1) from the information input unit. Through the system control unit 1, the tube control unit 4, the GAIN control unit, the ROI setting / pixel value control unit 6, the arm control unit 7, the injector control unit 8, the aperture control unit 9, and the imaging instruction display control unit are controlled. Information from each control unit is fed back to the system control unit 1,
Control for each control unit can be performed based on the fed back information.

When the above preparation is completed, when the DSA imaging sequence start instruction is issued from the imaging SW 11 to the system control unit 1, first, the aperture control unit 9 automatically starts the X-ray aperture up to the location where the ROI is designated. 12, the area is narrowed down so that X-rays are irradiated only to the portions necessary for imaging. Here, the X-ray diaphragm 12 is applied only in a direction perpendicular to the arm rotation axis. This is because, if the direction parallel to the rotation axis is narrowed down, information is interrupted depending on the shooting angle.

Then, the system controller 1 outputs a signal for performing mask image shooting to each controller, and mask image shooting is performed. When the arm 13 has moved to the set angle, a signal is sent to the system control unit 1, and the system control unit 1 outputs a signal informing each control unit that mask image capturing has ended, and mask image capturing ends.

At the same time, the arm 13 returns to the rotation start position. When returning to the rotation start position, the arm control unit 7 issues a signal notifying the system control unit 1 that it has returned to the rotation start position, and the system control unit 1 issues a signal for performing fluoroscopy to each control unit. The fluoroscopy is started.

At this time, the system control unit 1 transmits an injection start signal to the injector control unit 8 according to the result calculated earlier, and starts the injection of the contrast agent. Further, the detection gain of the detector 15 is also automatically changed by the system control unit 1 according to the fluoroscopic condition and fed back to the gain control unit 5. At this time, the arm rotation and photographing are not yet started. The X-ray system monitors the pixel density of the designated ROI by the ROI setting / pixel value control unit 6. At this time R
A change in density of a specific pixel in the OI may be detected, or an average density of an arbitrary number of pixels in the ROI may be detected.

When the injection of contrast medium is started and the timing of X-ray exposure comes based on the result calculated earlier, the system control unit 1 switches from the fluoroscopic X-ray condition to the imaging X-ray condition. At this time, the system control unit 1 switches the gain control unit 5 so that the detection gain on the detector 15 side is switched for photographing.
Signal. The X-ray generation and detector 15 gain switching signal may be output as early as 1 second, for example, when it takes time to switch the X-ray condition. When each condition is completely switched, the system control unit 1 outputs a signal to each control unit so as to automatically start the imaging of the contrast image, that is, the arm rotation operation and the imaging operation. Thereby, contrast image photographing is started.

When the arm 13 reaches the rotation end angle, the arm controller 7 outputs a signal notifying the system controller 1 that the rotation has ended. Based on this signal, the system control unit 1
Outputs a signal notifying each control unit that the contrast image capturing has been completed. Here, at the same time as the contrast image capturing is completed or just before it is completed, the injector 14
The system control unit 1 may output a signal to the injector control unit 8 so as to stop the contrast medium injection. Based on the signal output from the system control unit 1, the detector 15 causes the gain control unit 5 to turn off the detection gain at the same time as the contrast image capturing is completed.

It should be noted that a constant value or threshold value that determines a change in density value in the ROI, a change amount per unit time of the density value in the ROI, and the like can be arbitrarily changed.

The embodiment described above is described in order to facilitate understanding of the present invention, and is not described in order to limit the present invention. Therefore, each element disclosed in the above embodiment includes all design changes and equivalents belonging to the technical scope of the present invention.

1 ... System control unit 1
2 ... Information input / pointing device 3 ... Image display unit 4 ... Tube display unit 5 ... Gain control unit 6 ... ROI setting / pixel value control unit 7 ... Arm control unit 8 ... Injector control unit 9 ... Aperture control unit 12 ... X Line stop 13 ... Arm 14 ... Injector

Claims (1)

In an X-ray diagnostic apparatus capable of taking a three-dimensional contrast image of a blood vessel of a subject,
Contrast agent capable of measuring the contrast agent injection start time, the time when the contrast agent reaches the target area on the image, and the time when the contrast agent has flowed out based on the contrast image or fluoroscopic image of the subject imaged in advance Dynamic measurement means;
Calculation for obtaining X-ray exposure start time, X-ray exposure end time, contrast agent injection amount, injection start time, injection end time, and injection speed based on the result of the contrast agent dynamic measurement means by predetermined calculation processing Means,
Operation control means for controlling the photographing timing and the injector operation based on the calculation result by the calculation means;
An X-ray diagnostic apparatus comprising: