JP2007175399A - X-ray ct apparatus and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To highly efficiently execute a test injection at a low exposure. <P>SOLUTION: This X-ray CT apparatus is provided with a scan gantry section scanning a subject with X-ray fan beam, a radiographing table for mounting a subject, and a control section controlling the respective sections and reconstructing the CT image of the subject based on the scan data read by the scan gantry section. This control method of the X-ray CT apparatus executes a scan reading step executing a helical shuttle scan on a region including a plurality of interest regions S2, S3 and S4 in the body axis direction of the subject a prescribed time after injecting angiographic contrast medium into the subject, and a CT value time change computing step reconstructing the CT images of the respective interest regions S2, S3 and S4 based on the read scan data and finding the time change of the CT values in the interest regions based on the acquired CT values. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an X-ray CT apparatus and a control method thereof. More specifically, the present invention controls a scanning gantry unit that scans and scans a subject with an X-ray fan beam, an imaging table that mounts the subject, and the above-described units. The present invention relates to a control method for an X-ray CT apparatus including a control unit that reconstructs a CT tomographic image of a subject based on scan data read by a scanning gantry unit.

  An angiographic CT examination is often performed for the purpose of diagnosing a tumor, aneurysm, or the like from a surrounding tissue. In order to properly perform such a contrast examination, it is necessary to perform imaging at the timing when the contrast medium reaches the region of interest, but the progress of the contrast medium is not only of individual differences (heart rate, blood pressure, etc.) but also of interest. Since there is also a difference depending on the difference in the region (blood vessel thickness), conventionally, the contrast agent arrival time is determined by injecting a contrast agent in advance on a trial basis and observing the temporal change in the CT value at the region of interest. A so-called test injection for measuring was performed.

  However, conventionally, since only one place can be measured by one test injection, the measurement at a plurality of places cannot be performed efficiently at one time.

In this regard, conventionally, the imaging speed (top plate movement speed and / or gantry rotation speed) is controlled in real time so that the CT value in a tomographic image that changes with time due to contrast medium injection falls within a predetermined threshold. On the other hand, an X-ray CT apparatus capable of continuously performing a contrast examination of a plurality of regions of interest along the body axis direction is known (Patent Document 1).
JP 2005-160784 (Abstract, FIG. 2)

  However, if the CT value in the tomographic image is determined in real time, the CT value of the contrast agent that is actually detected is the region of interest (ROI: Region of Interest) (aorta, artery, organ, etc.). ) And shape (thickness of the blood vessel, etc.), it is necessary to allow the threshold value to have a considerable width. For this reason, it is not always possible to perform actual imaging at the timing of the optimal CT value. Not exclusively. In addition, if the method of performing the actual imaging after waiting for the CT value of the region of interest to become a predetermined value or more, there is often a case where unnecessary exposure is given to the waiting time in a region where the speed of the contrast agent is low. Cannot diagnose exposure.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide an X-ray CT apparatus capable of performing test injection efficiently with low exposure and a control method thereof.

The above problem is solved by the configuration of FIG. That is, the control method of the X-ray CT apparatus of the present invention (1) controls the scanning gantry unit that scans and scans the subject with the X-ray fan beam, the imaging table on which the subject is mounted, and the above-described units. And a control unit for reconstructing a CT tomogram of a subject based on scan data read by a scanning gantry unit, wherein the control unit injects an angiographic contrast agent into the subject. A scan reading step of performing helical shuttle scan reading on a region including a plurality of regions of interest S2, S3, S4 in the body axis direction of the subject after elapse of a predetermined time, and based on the read scan data CT values for reconstructing CT tomographic images of the regions of interest S2, S3, and S4, and for obtaining temporal changes in the CT values at the regions of interest based on the obtained CT values And it executes the between change computing step.

  In the present invention (1), the region including the plurality of regions of interest S2, S3, and S4 in the body axis direction is imaged a plurality of times by the helical shuttle scan, and the time change of the CT value at each region of interest is efficiently performed with little exposure. It can be detected. In addition, based on the time change of the CT value at each region of interest, it is possible to easily and accurately set each optimum reading start time when each region of interest is imaged in real time.

  The helical shuttle scan refers to a scan that reciprocally moves the relative positional relationship between the subject and the X-ray fan beam in the body axis direction while helically scanning the subject. This reciprocation includes a case where the scanning gantry is fixed and the imaging table is reciprocated and a case where the imaging table is fixed and the scanning gantry is reciprocated.

  Further, the above problem is solved by, for example, the configuration of FIG. In other words, the control method of the X-ray CT apparatus of the present invention (2) controls the scanning gantry unit that scans and scans the subject with the X-ray fan beam, the imaging table on which the subject is mounted, and the above-described units. And a control unit for reconstructing a CT tomogram of a subject based on scan data read by a scanning gantry unit, wherein the control unit injects an angiographic contrast agent into the subject. After a predetermined time has elapsed, a helical shuttle scan is performed on a region including a plurality of regions of interest S2 and S4 in the body axis direction of the subject, and only when scanning the regions of interest S2 and S4. A scan reading step for performing X-ray exposure, and CT tomograms of the regions of interest S2 and S4 are reconstructed based on the read scan data, and each obtained CT And executes the CT value time variation calculation step of obtaining a time change in CT value of each region of interest based on.

  In the present invention (2), since the helical shuttle scan is performed on the region including the plurality of regions of interest S2 and S4 of the subject, the X-ray exposure is performed only when scanning the regions of interest S2 and S4. The exposure of the subject can be further reduced.

  The above problem is solved by the configuration of FIG. 7, for example. That is, the X-ray CT apparatus control method of the present invention (3) controls the scanning gantry unit that scans and scans the subject with the X-ray fan beam, the imaging table on which the subject is mounted, and the above-described units. , A control method for an X-ray CT apparatus comprising a control unit for reconstructing a CT tomogram of a subject based on scan data read by a scanning gantry unit, wherein the control unit is configured to inject an angiographic agent. A scan reading step of sequentially performing helical shuttle scan reading according to a predetermined scan sequence for a plurality of regions including a plurality of regions of interest S2, S3, S4 in the body axis direction of the subject after elapse of a predetermined time; Based on the read scan data, a CT tomogram of each region of interest S2, S3, S4 is reconstructed, and each interest is based on the obtained CT values. And executes the CT value time variation calculation step of obtaining a time change of the CT values in the position.

  In the present invention (3), by sequentially performing helical shuttle scan reading on a plurality of regions of interest, it is possible to efficiently scan a plurality of parts with a high repetition density. Accordingly, the peak of the CT value can be detected with higher accuracy (density), and the optimum reading start time can be set for each region of interest based on this.

  The predetermined scan sequence is a scan sequence roughly estimated in advance so that a helical shuttle scan can be sufficiently performed for each region of interest (scan speed, number of shuttle repetitions for each region, etc.) It is.

  In the present invention (4), in each of the present inventions (1) to (3), the CT value peak at each region of interest is obtained from the contrast agent injection based on the time change of each obtained CT value. The delay time calculating step for obtaining the delay time is further executed.

  According to the present invention (4), by analyzing the temporal change (curve) of the CT value at each region of interest (detecting a peak or the like), each region of interest is subsequently produced based on the delay time corresponding to each peak. The optimum reading start time (and reading end time in some cases) when performing contrast imaging can be set easily and accurately.

  In addition, the X-ray CT apparatus of the present invention (5) controls the scanning gantry unit that scans and scans the subject with the X-ray fan beam, the imaging table on which the subject is mounted, and the above-described units, and the scanning gantry unit. An X-ray CT apparatus comprising a control unit for reconstructing a CT tomographic image of a subject based on the scan data read in step 1, wherein the control unit passes a predetermined time after an angiographic contrast agent is injected into the subject Thereafter, scan reading means for performing helical shuttle scan reading on a region including a plurality of regions of interest in the body axis direction of the subject, and reconstructing a CT tomographic image of each region of interest based on the read scan data And a CT value time change calculating means for obtaining a time change of the CT value in each region of interest based on the obtained CT values.

  In addition, the X-ray CT apparatus of the present invention (6) controls the scanning gantry unit that scans and scans the subject with the X-ray fan beam, the imaging table on which the subject is mounted, and the above-described units, and the scanning gantry unit. An X-ray CT apparatus comprising a control unit for reconstructing a CT tomographic image of a subject based on the scan data read in step 1, wherein the control unit passes a predetermined time after an angiographic contrast agent is injected into the subject Thereafter, a helical shuttle scan is performed on a region including a plurality of regions of interest in the body axis direction of the subject, and a scan reading unit that performs X-ray exposure only at the time of scan reading of each region of interest; CT that reconstructs a CT tomographic image of each region of interest based on the scanned data, and calculates the time change of the CT value in each region of interest based on the obtained CT values In which and a time change calculating means.

  In the present invention (7), in the present invention (6), the scan reading means makes the scan pitch (velocity) in the body axis direction faster than usual in the section where X-ray exposure is not performed. Accordingly, the exposure of the subject can be further reduced, and each region of interest can be scanned at a higher repetition density, so that the peak timing of the CT value can be detected with higher accuracy.

  In addition, the X-ray CT apparatus of the present invention (8) controls a scanning gantry unit that scans and scans a subject with an X-ray fan beam, an imaging table on which the subject is mounted, and the above-described units, and a scanning gantry unit. An X-ray CT apparatus comprising a control unit for reconstructing a CT tomographic image of a subject based on the scan data read in step (i), wherein the control unit is configured to pass the predetermined time after the angiographic agent is injected. Scan reading means for sequentially reading a helical shuttle scan in accordance with a predetermined scan sequence for a plurality of regions including a plurality of regions of interest in the body axis direction of the subject, and each region of interest based on the read scan data CT value time change calculation means for reconstructing a CT tomographic image and obtaining time change of the CT value at each region of interest based on the obtained CT values It is those with a.

  In the present invention (9), in each of the present inventions (5) to (8), each of the steps from the injection of the contrast agent to the peak of the CT value at each site of interest is obtained based on the temporal change of the obtained CT values. The apparatus further includes a delay time calculating means for obtaining the delay time.

In the present invention (10), in the above-mentioned present invention (8), when the scan reading means shifts to the scan reading of the adjacent region of interest, at least one round-trip of the region including both adjacent regions of interest is included. Helical shuttle scan reading is performed. Accordingly, it is difficult for the CT value to be lost in the transition portion between the regions of interest.

  In the present invention (11), in the present inventions (4) to (10), the imaging table can reciprocate in the direction of the subject body axis, and the scan reading means is an imaging table with respect to the opening of the scanning gantry section. The subject is subjected to a helical shuttle scan by reciprocating.

  In the present invention (12), in the above-mentioned present inventions (4) to (10), the scanning gantry section can reciprocate in the direction of the subject body axis, and the scan reading means can move the subject mounted on the imaging table. Thus, a helical shuttle scan of the subject is performed by reciprocating the scanning gantry. Some angio CT cymtems move the scanning gantry when scanning a subject, but the present invention is suitable for application to such a system.

  As described above, according to the present invention, since actual imaging can be predicted more accurately by test injection, it greatly contributes to improving the reliability and safety of CT imaging accompanied with angiography.

  Hereinafter, a plurality of preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the same reference numerals denote the same or corresponding parts throughout the drawings. FIG. 1 is a diagram showing a configuration of an X-ray CT apparatus according to an embodiment. This apparatus includes a scanning gantry unit 30 that scans and scans the subject 100 with an X-ray fan beam XLFB, an imaging table 20 that places the subject 100 and moves it in the direction of the body axis CLb, and the remote units 30 and 20. An operation console unit 10 that performs control and is operated by an engineer, a doctor, or the like is provided.

  In the scanning gantry 30, 31 is a rotary anode type X-ray tube, 31 A is an X-ray controller, 32 is a collimator for limiting the X-ray slice width, 32 A is a collimator controller, and 33 is a large number aligned in the channel CH direction ( The multi-X-ray detector 34 in which X-ray detection elements (n = 1000) are arranged in a plurality of rows in the direction of the body axis CLb, generates projection data of the subject based on the detection signal of the X-ray detector 33. A data acquisition system (DAS: Data Acquisition System) 35 is a gantry that rotatably supports the X-ray imaging system around the subject body axis, and 35A is a rotation control unit for the gantry 35.

  In the operation console unit 10, 11 is a central processing unit that performs main control and processing (scan control, CT tomographic image reconstruction processing, etc.) of the X-ray CT apparatus, 11a is its CPU, 11b is RAM and ROM used by the CPU 11a. Main memory (MM) consisting of, etc., 12 is a command and data input device including a keyboard and mouse, 13 is a display device (CRT) for displaying scan plan information and CT tomograms, 14 is scanned with CPU 11a A control interface for exchanging various control signals CS and monitor signals MS between the gantry unit 30 and the imaging table 20, 15 a data collection buffer for temporarily storing projection data from the data collection unit 34, and 16 for data Projection data from the acquisition buffer 15 is stored and stored, and various applications necessary for the operation of the X-ray CT apparatus A tio emission programs and various arithmetic / correction have secondary storage device stores the data file or the like for (hard disk device).

Next, a basic imaging operation by this X-ray CT apparatus will be described. The subject 100 is irradiated with the X-ray beam XLFB from the X-ray tube 31 with the subject 100 positioned in the cavity of the scanning gantry 30. In this state, the X-ray fan beam XLFB from the X-ray tube 31 passes through the subject 100 and enters the detector rows of the X-ray detector 33 all at once. The data collection unit 34 generates projection data g (X, θ) corresponding to each detection row output of the X-ray detector 33 and stores these in the data collection buffer 15. Here, X represents the channel number of the detector, and θ represents the projection (view) angle. Further, the X-ray projection similar to the above is performed at each view angle θ where the scanning gantry 35 is slightly rotated, and thus projection data for one rotation of the scanning gantry is collected and accumulated. At the same time, the imaging table 20 is moved intermittently / continuously in the direction of the body axis CLb in accordance with the axial / helical scan method, thus collecting and accumulating all the projection data for the required imaging area of the subject, It is stored in the storage device 16. Then, the CPU 11a reconstructs a CT tomographic image of the subject 100 based on the projection data obtained after the end of all the scans or in parallel with the scans, and displays this on the display device 13.

  In the present embodiment, a detailed description will be given of a case in which the time when the contrast agent that has passed through the heart reaches a plurality of regions of interest in the body axis direction is efficiently obtained at once by test injection using such an X-ray CT apparatus. To do. In this case, the imaging table 20 includes a top plate 21 that is mounted with the subject 100 and is movable in the body axis direction. The top plate 21 reciprocates in the gantry cavity at a constant speed (variable speed in some cases). Is possible.

  FIG. 2 is a flowchart of X-ray CT imaging processing according to the embodiment, and shows basic processing common to several scanning methods described later. Preferably, after performing a scout scan (corresponding to two-dimensional X-ray imaging) of the subject 100 in advance, this process is entered. In step S11, scan parameters for a helical shuttle scan accompanying the subsequent test injection to the subject are set.

  FIG. 3 shows an example scan parameter setting screen. After the previous scout scan is completed, a scan setting screen 13A for the subsequent helical shuttle scan is displayed on the display unit 13, and a technician or the like clicks or inputs a necessary scan parameter with a mouse. In this example, the process in which the angiographic agent injected into the vein of the arm reaches the abdominal aorta from the heart through the ascending aorta, descending aorta, and thoracic aorta is a monitoring target, and scan parameters in one example are as follows.

Scan type = helical shuttle scan Scan start position = Z1
Scan reversal position = Z5
Scan sequence = Z1 and Z5 are simply reciprocated over 120 seconds. The scan starts on the subject's scout image 100. A straight line representing the reversal positions Z1 and Z5 is displayed. The plan can be confirmed or changed.

  In step S12, an engineer or the like sets recon parameters. In FIG. 3, the recon parameters for determining the temporal change of each CT value are set for a plurality of regions of interest S2, S3, S4 in the direction of the subject body axis. Each slice position S2, S3, S4 that reconstitutes a tomographic image of a region of interest (in this example, a blood vessel portion) corresponds to each scan position Z2, Z3, Z4 in the body axis direction. In step S13, input of a confirmation “CONFIRM” button is awaited.

  Thus, when the engineer or the like eventually determines that the “CONFIRM” button can be input, an angiographic agent is injected into the vein of the arm of the subject and the “CONFIRM” button is pressed. Thereby, the processing preferably proceeds to step S14 after waiting for a predetermined time required for the injected contrast agent to pass through the heart and reach the ascending aorta.

In step S14, a helical shuttle scan is performed for the range that covers the scan range of FIG. 3, and in step S15, the projection data is collected and finally stored and stored in the hard disk device 16. An example of the helical shuttle scan is a scan in which the subject (top plate 21) is reciprocated not only in one direction but also in the longitudinal direction of the body axis while performing a helical scan of the subject. Here, the helical scan refers to a scan in which the subject (top plate 21) is continuously moved in the body axis direction at a constant speed while the subject is imaged while the gantry 35 is rotated at a constant speed. .

  FIG. 4 shows an example of an operation image of the helical shuttle scan. In FIG. 4A, in the forward helical scan, the top 21 is moved to the scan position from Z1 to Z2 in order to perform a helical scan in the range from Z1 to Z5 with the gantry 35 rotated at a constant speed. This is done by continuously conveying at a constant speed. In FIG. 4B, in the helical scan of the return path, the top 21 is scanned from Z5 to Z1 so that the subject can be helically scanned in the range of Z5 to Z1 while the gantry 35 is rotated at a constant speed. Is carried out continuously at a constant speed. The helical shuttle scan is performed by repeating the above operation continuously for a predetermined number of times (shuttle).

  Returning to FIG. 2, in step S16, it is determined whether or not the required scan sequence is completed. If not, the process returns to step S14. Thus, when the required scan sequence is finished, the process proceeds to step S17, and each projection data g (X, θ) necessary for image reconstruction of each slice plane S2, S3, S4 is sequentially extracted from the hard disk device 16. First, each projection data on the forward path is extracted, then each projection data on the return path is extracted, and thus projection data for the required number of shuttle times is extracted.

  In step S18, predetermined preprocessing (reference correction processing, interchannel sensitivity correction processing, etc.) is performed on each extracted projection data. In step S19, image reconstruction data h (X, θ) corresponding to each slice plane S2, S3, S4 is generated by a known data interpolation calculation process, and in step S20, the interest of each slice plane S2, S3, S4 is generated. Reconstruct a CT tomogram of the site (blood vessel, etc.). In step S21, the CT value of the blood vessel part (contrast agent) is obtained along the time axis. In step S22, the obtained CT tomographic images and the temporal change of the CT value of the blood vessel part (ROI) are displayed on the screen. Exit processing.

  In the above embodiment, the image reconstruction process after step S17 is started after completion of a series of helical shuttle scans. However, the present invention is not limited to this. In parallel with the progress of the helical shuttle scan, extraction of necessary projection data and reconstruction of CT tomograms that can be reconstructed are sequentially performed, and the obtained CT tomograms and CT values of the blood vessels are obtained each time. Immediately, real-time display (Auto View) may be performed on the display unit 13.

  FIG. 5 is a diagram for explaining the test injection imaging process according to the first embodiment. In this helical shuttle scan, the top 21 is reciprocated within the scan ranges Z1 to Z5 with the gantry 35 rotated at a constant speed. A simple case is shown. In the figure, the temporal change of the CT value in each region of interest S2, S3, S4 is also shown. After injecting the contrast agent at time t0, a helical shuttle scan of the subject is started sufficiently before the contrast agent flows out of the heart. If it takes 2 seconds for the helical scans of the outward paths Z1 to Z5, it also takes 2 seconds for the helical scans of the return paths Z5 to Z1, and makes one round trip in a total of 4 seconds. By repeating this, a helical shuttle scan is performed.

Inset (a) shows a reconstructed image of the blood vessel section. In general, the CT value of blood is about 30 to 40, whereas the CT value of the surrounding internal organs is around 50, so that sufficient contrast cannot be obtained in the reconstructed image of the blood vessel part as it is. Since the CT value of the blood vessel is about 200 to 300, the CT value of the blood vessel increases as time passes by being filled with the contrast agent.
It becomes possible to clearly diagnose the state of a blood vessel (an aneurysm or the like). Then, the CT value gradually decreases as the contrast medium passes.

  Now, paying attention to the region of interest S2, a reconstructed image of the region of interest S2 is obtained each time the backward and forward scans pass through the slice plane S2, and the CT value of the blood vessel portion at each time point is obtained. Furthermore, when the CT values at each time point are plotted with black dots and interpolated between the black dots with a smooth curve, an upwardly convex curve is obtained as shown in the figure. Therefore, when the peak point of the curve is obtained, it can be seen that a delay time t1 is required from the contrast agent injection start time t0 to the tomographic image of the region of interest S2 that is most stained with the contrast agent for the blood vessel S2. Thus, in the actual contrast examination, the optimum contrast examination for the region of interest S2 can be performed at low exposure by setting the contrast examination time having a predetermined time width before and after the delay time t1 as a reference. It can be done efficiently.

  Hereinafter, similarly, the delay times t2 and t3 corresponding to the regions of interest S3 and S4 are obtained with high accuracy. The CT values of the regions of interest S2 and S3 tend to gradually become lower due to dispersion / dilution with the progress of the contrast agent, and each delay time t1, t2, t3 and the passage time of each part ( With regard to the dullness of the peak shape, the blood vessels tend to become gradually smaller and larger and dull.

  According to the first embodiment, the time change of each CT value in a plurality of regions of interest in the body axis direction can be obtained efficiently with low exposure by test injection using a relatively simple helical shuttle scan. Accordingly, it is possible to set an appropriate time width before and after each peak in the actual imaging, thereby enabling the actual contrast examination to be performed efficiently and accurately with low exposure.

  FIG. 6 is a diagram for explaining test injection imaging processing according to the second embodiment, and shows a case where X-rays are exposed only during imaging of the regions of interest S2 and S4 of the subject. The reciprocating motion of the top board 21 (subject) is the same as that described in the first embodiment. In this example, since the blood vessel portion S2 is excluded from the region of interest, X-ray exposure is not performed in this section. In the figure, the scanning range to which X-rays are exposed is indicated by a wide band (filled), and the portion where X-rays are not exposed is indicated by dotted lines. Therefore, the exposure dose of the subject can be greatly reduced.

  In addition, it is possible to make the conveyance pitch of the top plate 21 in a portion where X-rays are not exposed faster than usual (shuttle variable pitch helical), and in this way, further reduction in exposure can be achieved.

  FIG. 7 is a diagram for explaining the test injection imaging process according to the third embodiment, and shows a case where the minimum necessary helical shuttle scan is repeatedly performed in the order of each region of interest S2, S3, S4 of the subject. In the figure, the top plate 21 in this case performs the minimum necessary first helical shuttle scan in the first range including the first region of interest S2, and then the second range including the second region of interest S3. The minimum necessary second helical shuttle scan is performed, and the minimum necessary third helical shuttle scan is performed in the third range including the third region of interest S4.

  In this case, it is preferable that at least one or more common helical shuttle scans be performed for a range including both the regions of interest S2 and S3 when the region of interest S2 to S3 is scanned as shown in the drawing. By doing so, it is possible to detect each CT value of the portion where the temporal change (curve) of each CT value overlaps in both regions of interest S2 and S3 without omission. The same applies to the transition region from the region of interest S3 to S4.

  For the scan sequence of how many helical shuttle scans are performed for each region of interest S2, S3, S4, past experience considering the position of each region of interest in the body axis direction and the thickness of the blood vessel part It is possible to roughly estimate in advance based on the rules.

  According to the third embodiment, the exposure amount of the subject can be further reduced by the configuration in which the minimum necessary helical shuttle scan is performed for each of the regions of interest S2, S3, and S4. In addition, since the helical shuttle scan with high repetition density is performed for each region of interest, the detection accuracy of the temporal change of the CT value is further improved.

  In each of the above embodiments, the CT value of one slice plane is monitored for each region of interest S2, S3, S4. However, the present invention is not limited to this. By monitoring the CT value also on the slice plane in the vicinity of each region of interest, it is possible to monitor the time change of the CT value with higher reliability.

  In the above embodiment, the CT value in the aorta is monitored, but the present invention is not limited to this. It goes without saying that the present invention can also be applied to the monitoring of CT values in organs.

  In each of the above embodiments, the case where the top plate 21 on which the subject is mounted is reciprocated in the body axis direction is described, but the present invention is not limited to this. Although not shown, it is obvious that the scanning gantry unit 30 may be reciprocated in the direction of the subject body axis while the top plate 21 is fixed.

  Further, although the preferred embodiment of the present invention has been described, it goes without saying that various changes in the configuration, control, processing, and combination of each part can be made without departing from the spirit of the present invention.

It is a figure which shows the structure of the X-ray CT apparatus by embodiment. It is a flowchart of the X-ray CT imaging process by embodiment. It is an image figure of the scan / recon parameter setting process by embodiment. It is an image figure of the helical shuttle scan by embodiment. It is a figure explaining the test injection imaging | photography process by 1st Embodiment. It is a figure explaining the test injection imaging | photography process by 2nd Embodiment. It is a figure explaining the test injection imaging | photography process by 3rd Embodiment.

Explanation of symbols

10 Operation console 11 Central processing unit 11a CPU
11b Main memory (MM)
12 Input device 13 Display device (CRT)
14 Control Interface 15 Data Collection Buffer 16 Secondary Storage Device (Hard Disk Device etc.)
DESCRIPTION OF SYMBOLS 20 Imaging table 21 Top plate 30 Scanning gantry part 31 X-ray tube 32 Collimator 33 Multi X-ray detector 34 Data acquisition system (DAS: Data Acquisition System)
35 Gantry

Claims (12)

A scanning gantry unit that scans and scans a subject with an X-ray fan beam, an imaging table on which the subject is mounted, and controls each of the above parts, and a CT tomogram of the subject based on scan data read by the scanning gantry unit A control method for an X-ray CT apparatus comprising a control unit for reconfiguring the control unit, wherein the control unit includes:
A scan reading step of performing a helical shuttle scan reading on a region including a plurality of regions of interest in the body axis direction of the subject after a predetermined time has elapsed since the angiographic agent was injected into the subject;
A CT tomographic image of each region of interest is reconstructed based on the read scan data, and a CT value time change calculating step for obtaining a time change of the CT value in each region of interest based on each obtained CT value is executed. A control method of an X-ray CT apparatus characterized by the above. A scanning gantry unit that scans and scans a subject with an X-ray fan beam, an imaging table on which the subject is mounted, and controls each of the above parts, and a CT tomogram of the subject based on scan data read by the scanning gantry unit A control method for an X-ray CT apparatus comprising a control unit for reconfiguring the control unit, wherein the control unit includes:
After a predetermined time has passed since the angiographic agent was injected into the subject, a helical shuttle scan is performed on a region including a plurality of regions of interest in the body axis direction of the subject, and scan reading for each region of interest is performed. A scan reading step for performing X-ray exposure only at the time,
A CT tomographic image of each region of interest is reconstructed based on the read scan data, and a CT value time change calculating step for obtaining a time change of the CT value in each region of interest based on each obtained CT value is executed. A control method of an X-ray CT apparatus characterized by the above. A scanning gantry unit that scans and scans a subject with an X-ray fan beam, an imaging table on which the subject is mounted, and controls each of the above parts, and a CT tomogram of the subject based on scan data read by the scanning gantry unit A control method for an X-ray CT apparatus comprising a control unit for reconfiguring the control unit, wherein the control unit includes:
A scan that sequentially reads helical shuttle scans according to a predetermined scan sequence for a plurality of regions including a plurality of regions of interest in the body axis direction of the subject after a predetermined time has elapsed since the angiographic contrast agent was injected A reading step;
A CT tomographic image of each region of interest is reconstructed based on the read scan data, and a CT value time change calculating step for obtaining a time change of the CT value in each region of interest based on each obtained CT value is executed. A control method of an X-ray CT apparatus characterized by the above. The delay time calculating step for obtaining each delay time from the injection of the contrast agent until the peak of the CT value at each region of interest is obtained based on the time change of each obtained CT value. The control method of the X-ray CT apparatus as described in any one of 1 thru | or 3. A scanning gantry unit that scans and scans a subject with an X-ray fan beam, an imaging table on which the subject is mounted, and controls each of the above parts, and a CT tomogram of the subject based on scan data read by the scanning gantry unit An X-ray CT apparatus comprising a control unit for reconfiguring the control unit,
Scan reading means for performing helical shuttle scan reading on a region including a plurality of regions of interest in the body axis direction of the subject after a predetermined time has elapsed since the angiographic agent was injected into the subject;
CT value time change calculating means for reconstructing a CT tomographic image of each region of interest based on the read scan data and calculating a time change of the CT value in each region of interest based on each obtained CT value. X-ray CT apparatus that is characterized. A scanning gantry unit that scans and scans a subject with an X-ray fan beam, an imaging table on which the subject is mounted, and controls each of the above parts, and a CT tomogram of the subject based on scan data read by the scanning gantry unit An X-ray CT apparatus comprising a control unit for reconfiguring the control unit,
After a predetermined time has passed since the angiographic agent was injected into the subject, a helical shuttle scan is performed on a region including a plurality of regions of interest in the body axis direction of the subject, and scan reading for each region of interest is performed. Scan reading means for performing X-ray exposure only at the time of,
CT value time change calculating means for reconstructing a CT tomographic image of each region of interest based on the read scan data and calculating a time change of the CT value in each region of interest based on each obtained CT value. X-ray CT apparatus that is characterized. The X-ray CT apparatus according to claim 6, wherein the scan reading unit makes the scan pitch in the body axis direction faster than usual in a section where X-ray exposure is not performed. A scanning gantry unit that scans and scans a subject with an X-ray fan beam, an imaging table on which the subject is mounted, and controls each of the above parts, and a CT tomogram of the subject based on scan data read by the scanning gantry unit An X-ray CT apparatus comprising a control unit for reconfiguring the control unit,
A scan that sequentially reads helical shuttle scans according to a predetermined scan sequence for a plurality of regions including a plurality of regions of interest in the body axis direction of the subject after a predetermined time has elapsed since the angiographic contrast agent was injected Reading means;
CT value time change calculating means for reconstructing a CT tomographic image of each region of interest based on the read scan data and calculating a time change of the CT value in each region of interest based on each obtained CT value. X-ray CT apparatus that is characterized. 6. The apparatus according to claim 5, further comprising delay time calculating means for calculating each delay time from the injection of the contrast agent until a CT value peak is obtained at each site of interest based on the time change of each calculated CT value. X-ray CT apparatus as described in any one of thru | or 8. 9. The scan reading means performs helical shuttle scan reading of an area including both adjacent sites of interest over at least one round trip when transitioning to scan reading of adjacent sites of interest. X-ray CT system. The imaging table can reciprocate in the direction of the subject body axis, and the scan reading means performs a helical shuttle scan of the subject by reciprocating the imaging table with respect to the opening of the scanning gantry. The X-ray CT apparatus according to claim 4. The scanning gantry can reciprocate in the direction of the subject body axis, and the scan reading means can perform a helical shuttle scan of the subject by reciprocating the scanning gantry with respect to the subject mounted on the imaging table. An X-ray CT apparatus according to any one of claims 4 to 10, wherein:

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