Motion-Corrected Blipped CAIPIRINHA and SMS MRI
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Solution Overview
Problem
Conventional motion correction techniques for MRI scans cannot be combined with blipped Simultaneous Multi-Slice (SMS) and blipped Controlled Aliasing in Parallel Imaging Results in Higher Acceleration (CAIPIRINHA) techniques, leading to inconsistent gradient moment accumulation and corrupted image reconstruction due to motion-induced phase offsets.
Innovation Solution
Compensating for motion-induced phase offsets by adapting MR data acquisition parameters or during image reconstruction using motion data from tracking mechanisms, such as cameras or navigators, to account for phase shifts caused by object movement during blipped gradient applications in 3D k-space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional motion correction techniques are used, then motion artifacts are reduced, but they cannot be combined with blipped SMS or blipped CAIPIRINHA techniques, leading to corrupted image reconstruction
Solution Approach 1:
The patent introduces motion tracking mechanisms (such as optical tracking systems or navigator echoes) as intermediary systems that independently measure object motion during blipped SMS/CAIPIRINHA acquisition. These motion measurements serve as a mediator between the blipped parallel imaging technique and the reconstruction process, enabling both to coexist without corruption by providing external motion information that reconciles their incompatible gradient moment accumulation patterns.
2Productivity
If blipped gradients are applied for parallel imaging, then phase dispersion within volume is achieved, but motion-induced phase offsets are introduced that corrupt image reconstruction
Solution Approach 1:
The patent implements a feedback mechanism where motion tracking data is continuously acquired during the blipped gradient application and fed back into the reconstruction process. This feedback loop allows the system to measure the actual motion-induced phase offsets and compensate for them during reconstruction, thereby maintaining phase encoding accuracy despite the use of blipped gradients for accelerated imaging.
Solution Approach 2:
The patent changes the parameter compensation approach by introducing motion-dependent phase correction terms in the reconstruction algorithm. Instead of using fixed conventional motion correction parameters, the system dynamically adjusts phase correction parameters based on real-time motion tracking data, allowing accurate reconstruction even when blipped gradients introduce variable phase offsets due to object motion.
3Manufacturing precision
If motion tracking is implemented, then motion-induced phase offsets can be compensated, but system complexity increases
Solution Approach 1:
The patent employs self-service approaches where the MRI system itself generates internal navigator echoes or uses the blipped gradient structure to encode motion information that can be extracted and used for self-correction. This eliminates the need for external complex tracking systems by making the MRI system self-diagnosing and self-correcting for motion-induced phase offsets, thereby reducing overall system complexity while maintaining compensation accuracy.
Data Source
AI summary
Techniques are disclosed related to the compensation of phase offsets introduced into k-space lines as a result of encoding of blip gradients due when motion is present, which may be used for parallel magnetic resonance imaging (MRI) techniques such as blipped SMS or blipped CAIPIRINHA. The compensation of these additional phase offsets may prevent artifacts that would otherwise be present in the reconstructed images as a result of motion during the MRI scanning procedure. The additional phase offsets may be accounted for during the image acquisition phase of the MRI scan or, alternatively, during the image reconstruction phase.