CT Reconstruction via Segmented Projection Groups
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Solution Overview
Problem
Current CT and C-arm X-ray systems face limitations in determining three-dimensional reconstructions with direction-independent local resolution due to slow swiveling of the recording arrangement, which is too time-consuming for many medical applications, especially for perfusion sequences.
Innovation Solution
The method involves assigning image times and imaging parameters to projection images, combining them into reconstruction groups to achieve direction-dependent local resolution, allowing for the determination of a temporal sequence of three-dimensional reconstructions, even when the recording arrangement cannot swivel through a large enough angle for direction-independent local resolution, by using computer processing and interpolation techniques to create virtual images that match acquisition times within each group.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the recording arrangement swivels through a large angle to capture projection images for direction-independent local resolution reconstruction, then the reconstruction quality improves, but the acquisition time increases significantly
Solution Approach 1:
The patent segments the projection images into multiple reconstruction groups, where each group contains images with image times within a specific time interval. This allows parallel processing of multiple smaller reconstruction tasks instead of one large time-consuming reconstruction, thereby reducing overall acquisition time while maintaining acceptable resolution through the segmentation of the angular range into multiple swivel segments.
Solution Approach 2:
The patent applies partial action by determining that three-dimensional reconstructions with direction-dependent local resolution are sufficient for many medical applications, especially perfusion sequences. Instead of requiring complete direction-independent reconstructions, the system uses partial angular ranges (swivel segments less than 180 degrees) to achieve acceptable diagnostic quality faster, accepting that some directional resolution is compromised for the sake of time resolution.
2Measurement precision
If the recording arrangement swivels slowly to capture complete projection data, then measurement accuracy improves, but the temporal resolution deteriorates
Solution Approach 1:
The patent segments the projection images into multiple reconstruction groups based on time intervals, allowing multiple reconstructions to be processed in parallel. Each group uses a limited angular range captured during a short swivel motion, enabling temporal resolution to be improved while maintaining sufficient measurement precision through the segmented approach.
Solution Approach 2:
The patent implements periodic action by capturing projection images at regular time intervals during the swivel motion and assigning them to different reconstruction groups. This periodic sampling in time allows the system to reconstruct multiple time points from periodic swivel segments, improving temporal resolution while maintaining measurement precision through systematic periodic data collection.
3Productivity
If projection images are captured using a C-arm X-ray system with limited swivel angle, then acquisition speed improves, but the ability to determine direction-independent local resolution deteriorates
Solution Approach 1:
The patent segments the limited angular range of the C-arm system into multiple swivel segments, capturing projection images during each segment. By processing these segmented images into separate reconstruction groups and combining them through interpolation, the system achieves direction-independent local resolution despite the limited total swivel angle, while maintaining high acquisition speed through efficient use of the available angular range.
Solution Approach 2:
The patent creates virtual projection images through interpolation to compensate for the limited swivel angle of the C-arm system. These virtual images are generated by interpolating between real projection images captured during the limited swivel motion, effectively copying and extending the data to achieve complete directional coverage without requiring physical swivel through the full 180 degrees, thereby maintaining both speed and resolution.
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 enables the determination of three-dimensional reconstructions with improved time resolution, reducing artifacts and allowing for perfusion analyses, even with systems that cannot capture complete direction-independent reconstructions, thereby enhancing medical imaging capabilities.
Implementation Method 1
a recording arrangement which comprises at least an X-ray source and an X-ray detector
Data Source
AI summary
A number of two-dimensional projection images of a three-dimensional examination object are assigned image times and imaging parameters. The projection images are combined into reconstruction groups including projection images with image times specifically assigned or within a time interval specific to the reconstruction groups. The reconstruction groups are determined in such a way that three-dimensional reconstructions of the examination object with direction-dependent local resolution can be determined based on the projection images of the reconstruction groups; it is not possible to determine three-dimensional reconstructions of the examination object with direction-independent local resolution. Three-dimensional reconstructions of the examination are determined based on the projection images of the reconstruction groups. Reconstruction times are determined based on the image times assigned to the projection images of the reconstruction groups and assigned to the three-dimensional reconstructions. Further analyses are performed as a function of the temporal sequence of the three-dimensional reconstructions.