PET Image Reconstruction Motion Phase Correction
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Solution Overview
Problem
PET/CT image reconstruction is hindered by respiratory and cardiac motion artifacts, leading to mismatches between CT and PET data, which degrade the quality of PET images and affect diagnostic accuracy, particularly during chest or upper abdomen scans.
Innovation Solution
A method involving the acquisition of 3D CT and PET data, gating of PET data based on motion phases, registration of gated PET images, determination of motion vector fields, and correction of CT data to align with a reference motion phase, allowing for the reconstruction of high-quality PET images by matching motion phases between CT and PET data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If PET/CT scanning is performed during chest or upper abdomen examinations, then functional and structural information can be simultaneously acquired, but respiratory and cardiac motion cause mismatch between CT and PET data leading to image artifacts
Solution Approach 1:
The patent segments the continuous PET data into multiple motion phases using gating based on respiratory and cardiac motion signals. This divides the scanning process into discrete phases (e.g., end-expiration, end-inspiration, diastole, systole), allowing separate reconstruction of PET images for each phase. By segmenting the data, the system can match CT and PET images taken at corresponding motion phases, eliminating motion-induced mismatch artifacts while preserving the simultaneous acquisition benefit.
2Manufacturing precision
If motion gating is applied to PET data, then alignment between CT and PET images is improved, but scanning time and data processing complexity increase
Solution Approach 1:
The patent applies preliminary action by acquiring motion signals (respiratory and cardiac) simultaneously with the PET scanning process. These motion signals are recorded and stored as reference data before image reconstruction begins. During reconstruction, the pre-acquired motion signals are used to gate the PET data into appropriate motion phases, enabling precise alignment with CT images without requiring additional scanning time. The motion information is captured in advance and reused for multiple reconstruction purposes.
3Reliability
If multiple gated PET images are reconstructed, then motion artifacts are reduced, but computational complexity and processing time increase
Solution Approach 1:
The patent extracts only the essential motion information from the acquired PET data by gating it according to pre-determined motion phases. Instead of processing all PET data uniformly or creating excessive intermediate images, the system extracts and reconstructs only the specific motion phase images that are clinically relevant (e.g., end-expiration and end-inspiration phases for chest exams). This selective extraction reduces computational complexity while maintaining the reliability benefits of motion-corrected imaging.
Data Source
AI summary
A method may include: obtaining a 3D CT image of a scanning area of a subject; obtaining PET data of the scanning area of the subject; gating the PET data based on a plurality of motion phases; reconstructing a plurality of gated 3D PET images; registering the plurality of gated 3D PET images with a reference 3D PET image; determining a motion vector field corresponding to a gated 3D PET image of the plurality of gated 3D PET images based on the registration; determining a motion phase for each of the plurality of CT image layers; correcting, for each of the plurality of CT image layers, the CT image layer with respect to a reference motion phase; and reconstructing a gated PET image with respect to the reference motion phase based on the corrected CT image layers and the PET data.