MRI Motion Compensation via Inverse-Consistent Registration
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Solution Overview
Problem
Magnetic resonance imaging (MRI) is hindered by patient motion, leading to image blurring and ghosting, with existing methods like prospective approaches requiring extra clinical setup and retrospective methods sacrificing image efficiency or being computationally costly.
Innovation Solution
The implementation of inverse-consistent non-rigid registration for motion compensation in MRI reconstruction, which determines motion between shots and incorporates it into the reconstruction process, decoupling motion estimation from compensation to reduce computational costs and enable efficient, automated motion correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If retrospective gating is used to compensate for motion, then motion artifacts are reduced, but image efficiency is sacrificed by rejecting acquired data
Solution Approach 1:
The patent extracts the motion estimation problem from the reconstruction process by using separate navigator echoes to determine motion parameters. This allows motion compensation to be applied without rejecting acquired data, maintaining image efficiency while reducing motion artifacts.
Solution Approach 2:
The patent introduces navigator echoes as an intermediary to measure motion independently from the main imaging data. These navigator signals serve as mediators that provide motion information without requiring rejection of the primary acquired data, thus maintaining productivity while improving reliability.
2Device complexity
If a model of motion parameterized by basis signals is used, then deformation field estimation is avoided, but computational costs are largely increased leading to reconstruction time of 10 minutes
Solution Approach 1:
The patent segments the motion compensation process into distinct steps: first acquiring navigator echoes, then estimating motion parameters separately, and finally applying compensation during reconstruction. This segmentation allows for more efficient computation compared to solving large linear equations that couple motion estimation and compensation.
Solution Approach 2:
The patent performs motion estimation using navigator echoes before the main reconstruction process. By determining motion parameters in advance from the navigator data, the actual reconstruction can proceed more quickly without the need to solve complex coupled equations, significantly reducing overall reconstruction time.
3Reliability
If prospective approaches like breath-holding or respiratory gating are used, then motion is controlled during acquisition, but extra clinical set-up is required and performance is limited
Solution Approach 1:
The patent enables the system to self-measure motion through navigator echoes that are automatically acquired as part of the imaging sequence. This eliminates the need for external motion tracking devices or complex clinical set-up, while still providing reliable motion control through post-acquisition compensation.
Data Source
AI summary
Magnetic resonance reconstruction includes motion compensation. Inverse-consistent non-rigid registration is used to determine motion between shots. The motion is incorporated into reconstruction. The incorporation compensates for the motion resulting from the period over which the MR data is acquired.