Multi-Channel MRI Phase Images With SNR-Squared Vector Weighting
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Solution Overview
Problem
Existing magnetic resonance (MR) imaging methods for generating phase images require multiple scans to remove background phase, leading to reduced accuracy due to unequal signal-to-noise ratios across channels, which are not effectively addressed by current vector averaging techniques.
Innovation Solution
Adjust the lengths of MR signal vectors based on signal-to-noise ratios (SNR) for each channel to minimize phase uncertainty, using SNR-squared weighting, and then average these adjusted vectors to generate phase images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple scans are performed to remove background phase by computing phase difference, then phase-related applications can be achieved, but measurement precision deteriorates due to unequal signal-to-noise ratios across channels
Solution Approach 1:
The patent changes the weighting parameter from uniform weighting to SNR-squared weighting when combining phase images from multiple channels. This parameter change optimizes the contribution of each channel based on its signal quality, thereby reducing overall phase uncertainty and improving measurement precision while maintaining reliability of phase-related applications
2Device complexity
If simple vector averaging is used to combine multi-channel MR signals, then device complexity is reduced, but measurement precision worsens due to unequal signal-to-noise ratios across channels
Solution Approach 1:
The patent modifies the averaging process by introducing SNR-squared as a weighting parameter. Instead of simple uniform averaging, each channel's contribution is weighted by the square of its signal-to-noise ratio. This maintains computational simplicity while dramatically improving phase accuracy by giving more weight to high-quality channels and less to noisy channels
Data Source
AI summary
A method of generating a phase image of a region of interest of a patient, comprises: obtaining a plurality of adjusted magnetic resonance (MR) signal vectors by adjusting lengths of a plurality of MR signal vectors acquired by a MR imaging system having a plurality of channels, a length of a first of the plurality of MR signal vectors being adjusted based on a first signal-to-noise ratio for a first component MR signal vector on a first of the plurality of channels and a second signal-to-noise ratio for a second component MR signal vector on the first of the plurality of channels; and generating the phase image based on the plurality of adjusted MR signal vectors.