MRI Phase Measurement Disambiguation via Temporal Sampling
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Solution Overview
Problem
Magnetic resonance imaging (MRI) phase measurements are hindered by phase ambiguities, noise, and phase wrapping, which reduce spatial resolution and accuracy, and existing methods require phase unwrapping, denoising, and estimation of phase offsets, leading to artifacts and reduced resolution.
Innovation Solution
A system and method that use a joint acquisition and processing technique with optimal echo time steps to disambiguate phase measurements, eliminating the need for phase unwrapping and denoising, and leveraging statistical analysis to resolve phase ambiguities, allowing for high-resolution phase information without artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spatial regularization is used to handle phase ambiguities, then phase measurement reliability is improved, but spatial resolution deteriorates
Solution Approach 1:
The patent changes the temporal sampling parameters by acquiring phase images at multiple different time points. This temporal sampling approach allows disambiguation of phase values without requiring spatial regularization, thereby maintaining spatial resolution while improving phase measurement reliability through time-based differentiation.
Solution Approach 2:
The patent transitions from handling phase ambiguities in the spatial domain to the temporal domain by acquiring phase images at multiple time points. This dimensional shift from space to time allows resolution of phase ambiguities without compromising spatial resolution, as the disambiguation is achieved through temporal evolution analysis rather than spatial smoothing.
2Reliability
If phase unwrapping and denoising are performed, then phase measurement reliability is improved, but computation time increases
Solution Approach 1:
The patent performs preliminary action by acquiring multiple phase images at different time points during the imaging process itself. This temporal sampling is built into the acquisition protocol, allowing phase disambiguation to be achieved through the natural temporal evolution of the signal without requiring subsequent complex unwrapping and denoising computations.
Solution Approach 2:
The patent employs self-service by using the temporal evolution of phase signals to automatically disambiguate phase values. The system uses its own temporal sampling data to resolve ambiguities through differentiation and evolution analysis, eliminating the need for separate, computationally intensive phase unwrapping and denoising steps.
3Measurement precision
If multiple echo time steps are acquired, then phase measurement precision is improved, but acquisition time increases
Solution Approach 1:
The patent maintains continuity of useful action by acquiring phase images continuously at multiple time points during a single imaging sequence. This continuous temporal sampling allows precise phase measurements to be obtained without requiring multiple separate acquisitions, as the temporal evolution is captured in a continuous manner throughout the imaging process.
Solution Approach 2:
The patent implements periodic action by acquiring phase images at regularly spaced time intervals. This periodic temporal sampling provides sufficient data points to determine phase evolution and disambiguate phase values while maintaining efficient acquisition timing, balancing measurement precision with acquisition speed.
Data Source
AI summary
Described here are systems and methods for estimating phase measurements obtained using a magnetic resonance imaging (MRI) system such that phase ambiguities in the measurements are significantly mitigated. Echo time spacings are determined by optimizing phase ambiguity functions associated with the echo time spacings. Data is then acquired using a multi-echo pulse sequence that utilizes the determined echo spacings. Phase measurements are then estimated and images are reconstructed using a reconstruction technique that disambiguates the phase ambiguities in the phase measurements.