Attenuation Map Alignment Quality Metric for Emission Imaging
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Solution Overview
Problem
In emission imaging, misalignment between anatomical and emission images can lead to artifacts in attenuation-corrected emission images, particularly in cardiac imaging, due to incorrect identification of lung or tissue voxels, which affects the accuracy and reliability of the final image.
Innovation Solution
A method and apparatus for generating an attenuation map from anatomical images, reconstructing emission images with attenuation correction, and calculating a quality assurance metric to quantify alignment between the attenuation map and emission images, facilitating accurate registration and display of the emission images with metadata.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If attenuation correction is performed using anatomical images, then the accuracy of emission images is improved, but artifacts occur when misalignment exists between anatomical and emission images
Solution Approach 1:
The patent performs image registration between anatomical and emission images before attenuation correction is applied. This preliminary alignment ensures that the anatomical structures in the attenuation map correspond accurately to the emission sources, preventing misidentification of lung voxels as tissue voxels and avoiding artifacts in the final attenuation-corrected emission images
Solution Approach 2:
The patent implements a feedback mechanism where the registered anatomical image is used to generate an updated attenuation map that is then applied to correct the emission image. The process includes visual or automated verification of alignment quality, allowing iterative refinement of the registration to ensure accurate correspondence between anatomical structures and emission sources before final correction
2Measurement precision
If manual image registration is performed by radiologists, then alignment accuracy can be improved, but the complexity and time consumption of the process increases
Solution Approach 1:
The patent implements automated image registration algorithms that perform the alignment between anatomical and emission images without requiring manual intervention by radiologists. The system automatically identifies corresponding features in both images, computes transformation parameters, and applies the registration, thereby eliminating the need for complex manual registration procedures while maintaining high alignment accuracy
Solution Approach 2:
The patent replaces the manual mechanical process of visual image registration with an automated computational system. Instead of radiologists manually adjusting and comparing images, the system uses algorithmic image matching and transformation techniques to achieve precise alignment automatically, reducing both complexity and time consumption
3Device complexity
If sequential data acquisition is used in hybrid imaging systems, then mechanical misalignment between modalities occurs, but the system complexity is reduced
Solution Approach 1:
The patent performs image registration as a preliminary step before attenuation correction to compensate for mechanical misalignment that occurs during sequential data acquisition. By aligning the anatomical and emission images after acquisition but before correction, the system restores spatial correspondence without requiring simultaneous acquisition, thereby maintaining system simplicity while achieving accurate alignment
Data Source
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AI summary
An anatomical image data set and an emission image data set are acquired for a subject. An attenuation map is generated from the anatomical image data set. The emission image data set is reconstructed to generate an emission image. The reconstructing includes correcting for attenuation of emission radiation in the subject using the attenuation map. A value is calculated for a quality assurance (QA) metric quantifying alignment of the attenuation map with the emission image. The emission image is displayed or printed together with the calculated quality assurance metric. In some embodiments, prior to the reconstructing the attenuation map is registered with the emission image data set by performing a global rigid registration followed by a local non-rigid registration of a region of interest.