Automatic adjustment method for gynecological CT enhanced scanning
By adaptively adjusting the delay time of CT to enhance the scan and triggering the scan when the breathing cycle is stable, the problems of low efficiency and respiratory fluctuations in the prior art are solved, and high-quality CT image acquisition is achieved.
Patent Information
- Application Number
- CN202510430414.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-08
- Publication Date
- 2025-07-08
AI Technical Summary
Existing CT enhanced scans are inefficient when setting the trigger delay time and fail to effectively reduce the impact of breathing fluctuations on image quality.
Enhance the delay time of the CT scan by adaptive adjustment and triggering the scan when the breathing cycle is stable by measuring the test, combining wireless pressure sensors and video monitoring to monitor the breathing cycle, Kalman filtering fusion technology extracts the breathing cycle signal to determine the optimal scanning timing.
The impact of respiratory fluctuations on CT scan images is reduced, and the quality and scanning efficiency of CT images are improved.
Smart Images
Figure CN120267316A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of medical image processing, and particularly relates to an automatic adjustment method for enhanced CT scanning of the gynecology department. Background Art
[0002] CT scanning includes operations such as CT scout view, CT plain scan, and CT enhanced scan. Among them, in CT enhanced scan, after intravenous injection of a contrast agent, based on the difference in the absorption rate of the contrast agent by body tissues such as arterial blood vessels and venous blood vessels, multi-phase CT scans are performed by delaying different times to obtain CT images in three cases: arterial phase, venous phase, and delayed phase, so as to be able to detect lesions that were not detected during CT plain scan.
[0003] The trigger delay time for each phase of CT enhanced scan can be set in advance by the actual operating staff. When setting, the staff generally sets according to the standard phase and time window. Generally, the arterial phase usually starts scanning 30 seconds after injection of the contrast agent to capture the peak of vascular enhancement. The venous phase is generally performed 45 seconds after injection. At this time, the contrast agent has diffused from the artery to the venous system, and the delayed phase needs to adjust the time according to the nature of the lesion. Such settings all require the staff to judge and then adjust the time to a suitable position, with low efficiency and without considering the impact of CT scan artifacts caused by respiratory fluctuations during adjustment. Summary of the Invention
[0004] The purpose of the present invention is to provide an automatic adjustment method for enhanced CT scanning of the gynecology department, which can reduce the impact of respiratory fluctuations on CT scan images by adaptively adjusting the delay time during enhanced CT scan and triggering the scan when the respiratory cycle of the subject to be measured is stable.
[0005] To achieve the above purpose, the present application provides the following solutions:
[0006] The present application provides an automatic adjustment method for enhanced CT scanning of the gynecology department, including the following steps:
[0007] S1. Initialize and set the delay time corresponding to each scan phase;
[0008] S2. Start timing from the injection time of the subject to be measured. When the time reaches the delay time of the corresponding scan phase and it is monitored that the respiratory cycle of the subject to be measured is stable, trigger the start of scanning for the corresponding scan phase; obtain the scan image of the current scan phase;
[0009] S3. If the image quality of the scan image of the current scan phase meets the image requirements, continue timing until reaching the next scan phase;
[0010] S4. If the image quality of the scanned image in the current scan period fails to meet the image requirements, adjust the delay time for the next scan period. If the current scan period is the last scan period, no adjustment is required.
[0011] In some specific embodiments, the scan period includes an arterial phase, a venous phase, a delayed phase, and an injection excretion phase. Among them, initializing the delay time corresponding to each scan period includes setting the venous phase delay time, the arterial phase delay time, the delayed phase delay time, and the injection excretion phase delay time.
[0012] In some specific embodiments, when initializing the delay time corresponding to each scan period, select the minimum delay time within the delay range corresponding to the delay time of each scan period to initialize the delay time.
[0013] In some specific embodiments, the setting of the delay time in the delayed phase is adjusted correspondingly according to the lesion type determined by CT plain scan.
[0014] In some specific embodiments, the method for monitoring the stable respiratory cycle of the subject in step S2 is as follows:
[0015] Obtain the amplitude of the abdominal wall movement caused by the subject's respiration monitored in real time by the wireless pressure sensor array placed on the surface of the subject's abdomen;
[0016] Obtain the respiration waveform of the subject's chest and abdomen area monitored by video surveillance. Combine the amplitude of the abdominal wall movement and the respiration waveform, and extract the end-expiratory phase of the subject as the trigger condition when the subject's respiratory cycle is stable.
[0017] In some specific embodiments, perform Kalman filter fusion on the amplitude of the abdominal wall movement and the respiration waveform to generate a respiratory cycle signal, and extract the end-expiratory phase from the respiratory cycle signal.
[0018] In some specific embodiments, the method for determining a stable respiratory cycle is: when it is detected that the amplitude of the abdominal wall movement is less than the first threshold and the respiratory frequency calculated based on the corresponding respiration waveform at this time is within the preset range, it is determined that the current is a stable respiratory cycle.
[0019] In some specific embodiments, in step S4, when adjusting the delay time for the next scan period if the scanned image in the current scan period fails to meet the image requirements, estimate the scan time required for re-scanning the current scan period, and determine whether it exceeds the delay time for the next scan period. If so, move the delay time for the next scan period backward.
[0020] In some specific embodiments, the method for determining whether the image quality of the scanned image in the current scan period meets the image requirements is as follows:
[0021] After injecting the injection agent into the subject to be measured, set the target observation area, continuously monitor the change of the CT value of the target observation area. When the time reaches the arterial phase delay time and it is monitored that the respiratory cycle of the subject to be measured is stable, determine whether the CT value of the target observation area at this time reaches the preset threshold. If so, continue the scanning in the arterial phase; if not, wait for the preset time and then rescan.
[0022] The beneficial effects of the present invention are as follows:
[0023] By adjusting the delay time of each phase during the gynecological CT scanning process of the present invention and triggering the scanning by monitoring the stability of the respiratory cycle of the subject to be measured during the scanning of each phase, the influence of respiratory fluctuations on the CT scanning images can be reduced, and the quality of CT images can be improved. Description of the Drawings
[0024] Figure 1 It is a flowchart of an automatic adjustment method for enhanced gynecological CT scanning provided by an embodiment of the present application. Detailed Embodiments
[0025] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The description of at least one exemplary embodiment below is actually only illustrative and in no way restrictive of the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.
[0026] Unless otherwise specifically stated, the relative arrangements, numerical expressions, and numerical values of the components and steps described in these embodiments do not limit the scope of the present invention.
[0027] At the same time, it should be understood that, for the sake of convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship.
[0028] In addition, for the sake of clarity and conciseness, the descriptions of well-known structures, functions, and configurations may be omitted. Those of ordinary skill in the art will recognize that various changes and modifications can be made to the examples described herein without departing from the spirit and scope of the present disclosure.
[0029] The techniques, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods, and devices should be regarded as part of the authorization specification.
[0030] In all the examples shown and discussed here, any specific value should be construed as merely exemplary and not as a limitation. Thus, other examples of the exemplary embodiments may have different values.
[0031] Before introducing the specific embodiments of the present application, the concepts to be involved are described first:
[0032] Embodiment 1
[0033] As Figure 1 shown, this embodiment provides an automatic adjustment method for enhanced CT scanning of the gynecology department, including the following steps:
[0034] S1. Initialize and set the delay time corresponding to each scanning phase;
[0035] Enhanced CT scanning usually includes multi-phase scanning. Specifically, the scanning phases include the arterial phase, the venous phase, the delayed phase, and the contrast agent excretion phase. Among them, initializing and setting the delay time corresponding to each scanning phase includes setting the arterial phase delay time, the venous phase delay time, the delayed phase delay time, and the contrast agent excretion phase delay time.
[0036] When initializing and setting the delay time corresponding to each scanning phase, select the minimum delay time within the delay range corresponding to each scanning phase delay time to initialize and set the delay time. Generally speaking, the delay range of the arterial phase is usually 20 - 30 seconds after injecting the contrast agent, which is used to observe the early enhancement of the uterine artery and ovarian artery. The venous phase is carried out 60 - 70 seconds after injection to capture the enhancement characteristics of the lesion determined by plain CT scan during the venous return phase. The delayed phase is adjusted according to the lesion type determined by plain CT scan. For example, if the lesion type determined by plain CT scan is endometrial cancer or cervical cancer, then select a suitable initial value within 2 - 3 minutes for the delay time of the delayed phase as the initialized delayed phase delay time; for the lesion type of ovarian tumor, it is necessary to delay for 5 - 10 minutes to evaluate the contrast agent clearance.
[0037] Alternatively, to better set an accurate delay time for each subject to be measured, especially for the arterial phase as the starting scanning period, the delay time can be set through pre-scanning calibration. The method of pre-scanning calibration can be through a small-dose test. By intravenously injecting a small dose of injectant (usually 1 - 2 mL) into the subject to be measured, the peak time of the injectant in the target blood vessel (such as the uterine artery or internal iliac artery) is monitored by rapid low-dose CT scanning, and the arterial-phase delay trigger time is determined. According to the arterial-phase delay trigger time, the arterial-phase delay time of the subject to be measured is initialized. For example, if the peak time of the injectant obtained during the small-dose test is 25 seconds, the arterial-phase delay range can be determined as 25 - 30 seconds. For gynecological scans, the bladder, uterus, and ureters are closely adjacent in the pelvic cavity. During CT cross-sectional imaging, structural overlap may occur, increasing the difficulty of differentiating the source of lesions (such as differentiating tumors on the posterior wall of the bladder from uterine fibroids). Therefore, during CT enhanced scanning, the scanning time can be delayed, and the delay time in the delay period, i.e., the injectant excretion period (such as 10 - 15 minutes after the injectant is injected), can be appropriately extended. After the bladder is partially emptied, scanning is performed to reduce its density.
[0038] S2. Start timing from the injection time of the subject to be measured. When the time reaches the delay time of the corresponding scanning period and the respiratory cycle of the subject to be measured is monitored to be stable, trigger the start of scanning for the corresponding scanning period; obtain the scanning image of the current scanning period;
[0039] During CT scanning, one of the factors affecting the imaging quality of CT images is the motion artifacts that may be caused by the movement of the pelvic cavity driven by respiratory motion. Therefore, to suppress the influence of respiratory motion on CT scanning images, not only the delay time needs to be reasonably set, but also the scanning timing needs to be reasonably set.
[0040] Specifically, the method for monitoring the stability of the respiratory cycle of the subject to be measured in step S2 is as follows:
[0041] S21. Obtain the amplitude of the abdominal wall movement caused by the respiration of the subject to be measured, which is real-time monitored by the wireless pressure sensor array placed on the abdominal surface of the subject to be measured;
[0042] S22. Obtain the respiratory waveform of the chest and abdomen area of the subject to be measured monitored by video surveillance, and combine the amplitude of the abdominal wall movement and the respiratory waveform;
[0043] S23. Perform Kalman filter fusion on the amplitude of the abdominal wall movement and the respiratory waveform to generate a respiratory cycle signal, and extract the end-expiratory phase from the respiratory cycle signal.
[0044] Align the time stamps of the amplitude of the abdominal wall movement and the respiratory waveform to eliminate the time delay error between devices. The process of Kalman filter fusion is as follows:
[0045] Construct a state equation, use a constant velocity model to describe the periodic characteristics of respiratory motion, and define the state vector as the abdominal wall motion amplitude and its velocity (x = [d, v] T ), the covariance matrix F is dynamically adjusted based on the time interval of the respiratory cycle, and the state equation is expressed as:
[0046]
[0047] where, x k represents the state estimate at time k, x k-1 represents the state estimate at time k - 1, w k represents the process noise; according to the state equation, it can be known that the state at the current time can be predicted based on the state estimate and covariance matrix at the previous time;
[0048] Take the abdominal wall motion amplitude and the arc waveform as independent observation values to construct a multi-source observation equation;
[0049] z k = H·x k + v k , H = [1 0]
[0050] where, z k represents the observation value at time k, v k represents the observation noise;
[0051] In order to obtain the respiratory cycle signal, fuse the observation values, optimize the state estimate through the Kalman gain, and output a high-precision respiratory cycle signal; divide the respiratory cycle signal into the inhalation phase, exhalation phase, and rest period, and thus the end-expiratory phase of the subject can be judged and the best scan trigger window can be identified. By identifying the end-expiration (when the diaphragm position is at the lowest point) as the scan trigger timing, the motion artifacts caused by the movement of the thoracic and abdominal organs can be reduced.
[0052] S24. Extract the end-expiratory phase of the subject as the trigger condition when the respiratory cycle of the subject is stable.
[0053] The judgment method for a stable respiratory cycle is: when it is detected that the abdominal wall motion amplitude is less than the first threshold (<2 mm) and the respiratory frequency calculated based on the corresponding respiratory waveform at this time is within the preset range, it is determined that the current is a stable respiratory cycle.
[0054] When it is found during the real-time respiratory monitoring that the abdominal wall motion amplitude exceeds 5 mm, the scan needs to be paused and the subject is prompted to adjust the breathing rhythm. After the breathing is stable, the scan is restarted based on the respiratory phase predicted by the above Kalman filter to reduce motion artifacts.
[0055] S3. If the image quality of the scan image in the current scan period meets the image requirements, continue timing until the next scan period is reached;
[0056] S4. If the image quality of the scanned image in the current scan period fails to meet the image requirements, adjust the delay time for the next scan period; if the current scan period is the last scan period, no adjustment is required.
[0057] When adjusting the delay time for the next scan period because the scanned image in the current scan period fails to meet the image requirements, estimate the scan time required for re-scanning the current scan period, and determine whether it exceeds the delay time for the next scan period. If so, move the delay time for the next scan period backward.
[0058] The method for determining whether the image quality of the scanned image in the current scan period meets the image requirements is as follows:
[0059] After injecting the injection agent into the subject to be measured, set the target observation area, continuously monitor the change in the CT value of the target observation area. When the time reaches the arterial phase delay time and it is monitored that the respiratory cycle of the subject to be measured is stable, determine whether the CT value of the target observation area at this time reaches the preset threshold. If so, continue the scan in the arterial phase; if not, re-scan after waiting for the preset time. For example, when scanning the arterial phase for the first time, the obtained scanned image fails to meet the image requirements for clearly observing the artery. At this time, a low-dose additional scan can be immediately started (the tube current is reduced to 50 - 80 mA), and the delay time is set to re-scan within 10 - 15 seconds, without repeating the injection of the contrast agent.
[0060] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Based on the technical essence of the present invention, any simple modification, equivalent replacement, and improvement made to the above embodiments within the spirit and principle of the present invention still fall within the protection scope of the technical solution of the present invention.
Claims
1. An automatic adjustment method for enhanced CT scanning of the gynecology department, characterized in that, It includes the following steps: S1. Initialize and set the delay time corresponding to each scanning phase; S2. Start timing from the injection time of the subject. When the time reaches the delay time of the corresponding scanning phase and the respiratory cycle of the subject is monitored to be stable, trigger the start of scanning for the corresponding scanning phase; obtain the scanning image of the current scanning phase; S3. If the image quality of the scanning image of the current scanning phase meets the image requirements, continue timing until reaching the next scanning phase; S4. If the image quality of the scanning image of the current scanning phase fails to meet the image requirements, adjust the delay time of the next scanning phase. If the current scanning phase is the last scanning phase, no adjustment is required.
2. The automatic adjustment method for enhanced CT scanning of gynecology according to claim 1, wherein The scanning phases include the arterial phase, the venous phase, the delayed phase, and the contrast agent excretion phase. Among them, initializing and setting the delay time corresponding to each scanning phase includes setting the arterial phase delay time, the venous phase delay time, the delayed phase delay time, and the contrast agent excretion phase delay time.
3. The automatic adjustment method for enhanced CT scanning of gynecology according to claim 2, characterized in that, When initializing and setting the delay time corresponding to each scanning phase, select the minimum delay time within the delay range according to the delay range corresponding to the delay time of each scanning phase to initialize and set the delay time.
4. The automatic adjustment method for enhanced CT scan of gynecology according to claim 2, characterized in that, The setting of the delay time in the delayed phase is adjusted corresponding to the lesion type determined by CT plain scan.
5. The automatic adjustment method for enhanced CT scan of gynecology according to claim 2, characterized in that, In step S2, the method for monitoring the stable respiratory cycle of the subject is as follows: Obtain the amplitude of the abdominal wall movement caused by the subject's respiration monitored in real time by the wireless pressure sensor array placed on the abdominal surface of the subject; Obtain the respiratory waveform of the thoracic and abdominal regions of the subject monitored by video surveillance. Combine the amplitude of the abdominal wall movement and the respiratory waveform, and extract the end-expiratory phase of the subject as the trigger condition when the respiratory cycle of the subject is stable.
6. The automatic adjustment method for enhanced CT scanning of gynecology according to claim 5, characterized in that, Perform Kalman filter fusion on the amplitude of the abdominal wall movement and the respiratory waveform to generate a respiratory cycle signal, and extract the end-expiratory phase from the respiratory cycle signal.
7. The automatic adjustment method for enhanced CT scan of gynecology according to claim 5, characterized in that, The judgment method for a stable respiratory cycle is: when it is detected that the amplitude of the abdominal wall movement is less than the first threshold and the respiratory frequency calculated according to the corresponding respiratory waveform at this time is within the preset range, it is determined that the current is a stable respiratory cycle.
8. The automatic adjustment method for enhanced CT scanning of gynecology according to claim 5, characterized in that, In step S4, when adjusting the delay time of the next scanning phase if the scanning image of the current scanning phase fails to meet the image requirements, estimate the scanning time required for the current scanning phase to be scanned again, and judge whether it exceeds the delay time of the next scanning phase. If so, move the delay time of the next scanning phase backward.
9. An automatic adjustment method for enhanced CT scanning of gynecology according to claim 5, characterized in that, The method for judging whether the image quality of the scanning image of the current scanning phase meets the image requirements is as follows: After injecting the contrast agent into the subject, set the target observation area, continuously monitor the change of the CT value in the target observation area. When the time reaches the arterial phase delay time and the respiratory cycle of the subject is monitored to be stable, judge whether the CT value in the target observation area reaches the preset threshold at this time. If so, continue the scanning of the arterial phase. If not, wait for the preset time and then rescan.