Regional Digital Subtraction Angiography Mask Weighting
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Solution Overview
Problem
Digital subtraction angiography (DSA) and roadmapping techniques in x-ray imaging systems often lead to the loss of anatomical landmarks, which can delay diagnostics and error in the placement of interventional devices due to the removal of bony structures.
Innovation Solution
A method is provided where a mask is generated from a set of mask images, and applied to acquired image data with different weighting inside and outside a region of interest (ROI), allowing for dynamic adjustment of subtraction levels to visualize both vasculature and landmarks within the same image frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If image subtraction techniques are applied to remove unwanted bony structures, then visibility of vasculature is enhanced, but anatomical landmarks are lost
Solution Approach 1:
The patent applies different subtraction weights to different regions of the image. A first weight is applied within the region of interest (ROI) to enhance vasculature visibility, while a second weight is applied outside the ROI to preserve anatomical landmarks. This local differentiation resolves the contradiction by allowing full subtraction where needed (inside ROI) and partial or no subtraction where landmarks are needed (outside ROI).
2Measurement precision
If full mask subtraction is applied to enhance vasculature visualization, then diagnostic accuracy for vascular flow is improved, but placement accuracy of interventional devices deteriorates
Solution Approach 1:
The system applies a first weight within the ROI that enables accurate vascular flow diagnostics, while applying a second weight outside the ROI that preserves anatomical landmarks for accurate device placement. This local quality differentiation allows both diagnostic accuracy and placement precision to be maintained in their respective regions.
3Loss of information
If regional weighting of mask is applied to preserve landmarks outside ROI, then anatomical reference is maintained, but vasculature visibility inside ROI is reduced
Solution Approach 1:
The patent implements local quality by applying a first weight specifically within the ROI to maximize vasculature visibility, and a second weight outside the ROI to preserve anatomical landmarks. This regional differentiation ensures that each area receives the appropriate level of subtraction for its specific diagnostic needs.
4Adaptability or versatility
If dynamic adjustment of subtraction levels is enabled, then user flexibility in visualizing both vasculature and landmarks is improved, but system complexity increases
Solution Approach 1:
The system implements dynamics by allowing real-time adjustment of the first and second weights applied to different regions. Users can dynamically modify the subtraction levels within and outside the ROI based on diagnostic needs, providing flexibility without requiring complex manual processing of multiple images.
Solution Approach 2:
The system segments the image into two distinct regions (inside and outside ROI) and applies independent weighting to each segment. This segmentation simplifies the complexity by creating clear, manageable regions with distinct processing rules, making the system easier to control and adjust.
Data Source
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AI summary
Methods and systems are provided for generating regional digital subtraction angiography (DSA) images and roadmap images with landmarks. In one embodiment, a method comprises generating a mask from a set of mask images of an anatomy of a subject 710, and generating a masked image by applying the mask to acquired image data of the anatomy of the subject, including weighting the mask differently inside a region of interest (ROI) of the image than outside the ROI, the weighting inside ROI independent of the weighting outside the ROI 720. In this way, a user may be able to adjust a relative magnitude of subtraction inside and outside the ROI, and thus be able to visualize both vasculature and landmarks within the same image frame.