Projection Image Weighting for Motion-Robust Maskless Angiography
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Solution Overview
Problem
Existing maskless angiography techniques, such as DVA and VMA, are susceptible to patient motion artifacts due to temporal dynamics, which current 2D-2D registration methods fail to adequately address, particularly in non-rigid 3D motion scenarios.
Innovation Solution
A computer-implemented method that involves selecting a reference image from a set of projection images, determining weights based on similarity to the reference image, and using these weights to reduce motion artifacts by emphasizing images with similar motion states, thereby enhancing image quality through a weighted averaging or selection process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If maskless angiography (DVA/VMA) is used to avoid mask image recording, then signal-to-noise ratio is improved and radiation dose is reduced, but patient motion artifacts increase
Solution Approach 1:
The patent changes the temporal parameter by selecting projection images with similar temporal characteristics (similar contrast agent distribution patterns) to construct the evaluation image. This temporal parameter adjustment allows the system to capture motion-related information while minimizing artifacts from patient motion, resolving the contradiction between achieving high signal-to-noise ratio and reducing motion artifacts.
Solution Approach 2:
The patent dynamically selects and weights projection images based on their similarity to a reference image, rather than using a fixed combination approach. This dynamic adaptation allows the system to optimize the contribution of each projection image according to the actual motion state, thereby maintaining high signal-to-noise ratio while compensating for patient motion artifacts.
2Manufacturing precision
If standard 2D-2D registration is applied to correct motion, then single-slice translational motion is corrected, but non-rigid 3D motion artifacts remain
Solution Approach 1:
The patent moves from 2D image registration to 3D volumetric analysis by utilizing multiple projection images with different temporal characteristics. This dimensional extension allows the system to capture and correct for non-rigid 3D motions that cannot be addressed by conventional 2D-2D registration, thereby improving both motion correction accuracy and adaptability to various motion patterns.
Solution Approach 2:
The patent performs preliminary selection and weighting of projection images based on their temporal similarity to a reference image before constructing the final evaluation image. This preliminary action prepares the data in an optimized state that anticipates and compensates for various motion patterns, including non-rigid 3D motions, before the actual image reconstruction occurs.
Data Source
AI summary
A computer-implemented method for evaluating a set of projection images of an X-ray facility during maskless angiography in an examination region with a blood vessel structure includes: providing the set of projection images showing a passage of a contrast agent through the blood vessel structure in a covered passage time; selecting a reference image from the set of projection images; determining a weight for each projection image, wherein the weight for the projection images that do not correspond to the reference image is determined depending on a similarity of the projection image to the reference image and the weight for the reference image is determined not lower than the maximum of the weights for the other projection images; and ascertaining at least one evaluation image from the projection images, wherein the projection images are included in the ascertaining according to the determined weights.