Dynamic Sampling Rate for CT Perfusion Imaging
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Solution Overview
Problem
Computed tomography perfusion (CTP) scans expose patients to high radiation doses due to repeated scans at fixed intervals to observe contrast agent uptake and washout, which is not suitable for routine clinical practice and may impact quantitative perfusion measurements.
Innovation Solution
A method and system that dynamically vary the data acquisition sample rate during a contrast-enhanced perfusion scan based on the level of contrast in image data, reducing the sampling rate when not scanning a region of interest and increasing it during contrast uptake and washout to optimize radiation dose while maintaining accurate perfusion measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed high sampling rate is used during CTP scans to ensure accurate perfusion measurements, then measurement precision is improved, but radiation dose increases
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed sampling rate to a dynamic sampling rate that adjusts in real-time based on contrast agent presence. The system monitors image data continuously and modifies the sampling rate according to the detected contrast level, ensuring high measurement precision during contrast uptake while reducing radiation dose during baseline and washout phases.
Solution Approach 2:
The patent changes the sampling rate parameter dynamically based on contrast agent detection. By monitoring image data and identifying when contrast agent is present in the tissue, the system adjusts the sampling rate parameter to match the physiological state, thereby optimizing both measurement accuracy and radiation exposure.
2Object-affected harmful factors
If the sampling rate is reduced to lower radiation dose, then radiation dose is reduced, but perfusion measurement accuracy deteriorates
Solution Approach 1:
The system dynamically changes the sampling rate parameter based on the detected contrast agent level. During baseline periods without contrast, a lower sampling rate reduces radiation dose. When contrast agent is detected in the tissue, the sampling rate increases to capture the perfusion dynamics accurately, thus maintaining measurement precision while minimizing overall radiation exposure.
Solution Approach 2:
The patent implements a dynamic sampling strategy that adapts to the physiological state. The system continuously monitors image data to detect contrast agent presence and adjusts the sampling rate accordingly, creating a dynamic balance between radiation dose and measurement accuracy that responds to real-time physiological conditions.
3Measurement precision
If repeated scans are performed at pre-defined intervals to observe contrast uptake and washout, then perfusion status analysis is improved, but radiation dose increases
Solution Approach 1:
The patent applies periodic action by performing scans at strategically determined intervals rather than fixed pre-defined intervals. The system monitors contrast agent dynamics continuously and triggers scans periodically based on detected physiological events, such as contrast arrival or peak concentration, thereby optimizing perfusion status analysis while reducing unnecessary radiation exposure during intervals when contrast is not present.
4Measurement precision
If baseline scanning is performed before contrast uptake to establish reference values, then measurement reference accuracy is improved, but radiation dose increases
Solution Approach 1:
The patent applies partial action by performing baseline scanning with a reduced sampling rate rather than the full sampling rate used during contrast uptake. This approach captures sufficient baseline information to establish accurate reference values while minimizing radiation dose during the pre-contrast period, as the physiological changes during baseline are less critical than during active perfusion phases.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the overall radiation dose during CTP scans while ensuring accurate perfusion measurements by adjusting the sampling rate based on contrast levels, optimizing scan length and dose distribution.
Implementation Method 1
A radiation source 110, such as an x-ray tube, is supported by and rotates with the rotating gantry 104 around the examination region 106. The radiation source 110 emits generally fan, wedge, or cone shaped radiation that traverses the examination region 106.
Implementation Method 2
The contrast agent causes the x-ray density to temporarily increase as the contrast agent flows through the vascular tissue.
Data Source
AI summary
A method includes dynamically varying a data acquisition sample rate between at least two data acquisition sample rates during a contrast enhanced perfusion scan based on a level of contrast in image data generated during the scan. A system includes a computed tomography scanner and a console that controls the scanner based on a scan protocol, wherein the console dynamically varies a data acquisition sample rate of scanner during a contrast enhanced perfusion scan based on a level of contrast in the image data generated during the scan. A method for optimizing dose of a scan includes reducing a data acquisition sampling rate during at least a sub-portion of the scan in which a state of interest is not being scanned.