Four-Dimensional Angiography Vessel Overlap Artifact Reduction
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Solution Overview
Problem
Current methods for four-dimensional digital subtraction angiography suffer from artifacts due to vessel overlaps, leading to unreliable highlighting of vessels and reduced image quality, as the color intensity of pixels cannot be unequivocally assigned to overlapping vessel voxels, resulting in incorrect concentration representations.
Innovation Solution
A method that generates distribution data for the concentration of contrast agent across voxels based on temporal resolution, allowing for the accurate distribution of color intensity across voxels, reducing artifacts by predicting relative concentration levels and improving image quality without requiring absolute values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiplicative backprojection is used to reconstruct four-dimensional angiography dataset from projection images, then temporal resolution and image quality are improved, but vessel overlap artifacts occur causing unreliable highlighting of vessels
Solution Approach 1:
The patent performs preliminary actions by first reconstructing a three-dimensional vessel dataset from projection images before performing multiplicative backprojection. This preliminary 3D reconstruction provides a structural framework that constrains the subsequent 4D reconstruction, preventing unreliable vessel highlighting while maintaining image quality. The method also preliminarily identifies overlapping vessel regions to apply specialized processing.
Solution Approach 2:
The patent introduces an intermediary confidence map that stores reliability information about vessel highlighting. This confidence map acts as a mediator between the projection images and the final four-dimensional dataset, allowing the system to identify and correct artifacts in regions where vessel overlaps occur, thereby maintaining both image quality and reliability.
2Ease of manufacture
If color intensity of pixels is assigned to overlapping vessel voxels in multiplicative backprojection, then vessel visualization is achieved, but artifacts occur due to non-unequivocal assignment leading to incorrect concentration representation
Solution Approach 1:
The patent applies local quality by treating different spatial regions differently based on their characteristics. In regions where vessel overlaps occur, the method applies specialized processing including confidence map evaluation and artifact correction, while in non-overlapping regions, standard multiplicative backprojection is used. This localized approach maintains visualization quality while ensuring concentration accuracy in critical overlapping areas.
Solution Approach 2:
The patent changes parameters by introducing confidence values that quantify the reliability of color intensity assignments. When vessel overlaps are detected, the system modifies the reconstruction parameters to prevent erroneous highlighting, using the confidence map to adjust how color intensity is distributed among overlapping voxels, thereby maintaining both visualization and concentration accuracy.
3Reliability
If artifact reduction methods are applied to improve image quality, then vessel overlap artifacts are reduced, but computing power and processing time increase
Solution Approach 1:
The patent applies partial action by selectively processing only those regions where vessel overlaps occur, rather than applying complex artifact reduction algorithms to the entire dataset. The confidence map enables the system to identify problematic regions and apply targeted corrections only where needed, maintaining image quality while minimizing additional computational burden.
Solution Approach 2:
The patent performs preliminary identification of overlapping vessel regions and creates the confidence map before the main reconstruction process. This preliminary action allows the system to prepare correction strategies in advance, reducing the computational load during the actual artifact reduction phase and improving overall processing efficiency.
Data Source
AI summary
A method is provided for reducing artifacts occurring due to vessel overlaps in a four-dimensional angiography dataset acquired with administration of a contrast agent, wherein distribution data relating to a concentration of the contrast agent in the blood circulatory system is generated at the respective time points for a three-dimensional vessel dataset of a blood circulatory system or for a reduced dataset derived therefrom, e.g., by a trained function. A color intensity of a pixel showing a contrast agent filling state contained in a respective projection image of the blood circulatory system is distributed according to the distribution data at the respective time point of the acquired projection image across voxels of the vessel dataset that lie along a ray associated with the pixel in the backprojection.