Quantitative Perfusion Imaging via Beam Hardening Correction
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Solution Overview
Problem
Current cardiac CT perfusion measurements are hindered by beam hardening artifacts, which are not effectively addressed by existing technologies, and they require specialized, expensive energy-sensitive CT systems that are not readily available, also posing challenges with x-ray dose and noise reduction in dynamic imaging.
Innovation Solution
The implementation of automatic beam hardening correction techniques and super-voxel aggregation to reduce noise, enabling accurate blood flow estimates on any CT scanner, including those with low x-ray doses, and the use of robust estimation methods for precise flow measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If specialized energy-sensitive CT systems are used to eliminate beam hardening artifacts, then measurement precision is improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent converts the harmful beam hardening artifacts into useful information by analyzing their characteristics. The system deliberately uses the artifacts to derive material decomposition information, transforming a previously problematic phenomenon into a beneficial source of diagnostic data that enables quantitative perfusion measurements on conventional CT systems.
Solution Approach 2:
The patent introduces an intermediary processing layer that includes artifact reduction algorithms and material decomposition calculations. This intermediary layer processes the raw CT images to separate beam hardening effects from actual tissue properties, enabling accurate perfusion measurements without requiring specialized hardware.
2Object-affected harmful factors
If low x-ray dose is used in dynamic CT imaging, then patient safety is improved, but noise increases and measurement precision deteriorates
Solution Approach 1:
The patent merges information from multiple temporal phases and spatial regions by combining artifact-reduced images across different time points. This temporal and spatial integration allows the system to maintain measurement precision at low doses by accumulating signal information over time while the patient receives reduced radiation exposure.
Solution Approach 2:
The patent changes the processing parameters through iterative optimization, adjusting regularization strength and temporal weighting to maximize measurement precision at each dose level. The system adapts its processing parameters based on the actual noise characteristics observed in the low-dose data, maintaining accuracy without requiring high radiation doses.
3Measurement precision
If beam hardening correction is applied to enhancing myocardium, then measurement accuracy is improved, but processing complexity increases
Solution Approach 1:
The patent performs preliminary artifact reduction and material decomposition before the actual perfusion parameter calculation. By pre-processing the images to remove beam hardening effects and separate iodine contrast from tissue attenuation, the system simplifies subsequent flow measurements and avoids the need for complex iterative corrections during the main analysis phase.
Data Source
AI summary
Embodiments discussed herein facilitate system-independent quantitative perfusion measurements. One example embodiment is a method, comprising: accessing 4D (Four Dimensional) perfusion imaging data of a tissue, where the 4D perfusion imaging data comprises a plurality of 3D (Three Dimensional) stacks of perfusion imaging data over time; performing at least one of artifact reduction or post-processing on the 4D perfusion image data to generate processed 4D perfusion image data; computing one or more quantitative perfusion parameters for the tissue based at least in part on the processed 4D perfusion image data; and outputting a visual representation of the one or more quantitative perfusion parameters.