Dynamic Radial Spoke Sampling for MRI Reconstruction Flexibility
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Solution Overview
Problem
Radially sampled MRI methods, such as Golden ratio-based sampling, lack post-acquisition reconstruction flexibility and require complete uniformity of sampling density, which is often not feasible in dynamic imaging applications, limiting the ability to reconstruct images at multiple temporal resolutions.
Innovation Solution
The proposed method optimizes the angular increment between radial spokes for a predetermined set of reconstruction window sizes, achieving near-optimal sampling uniformity within these restricted sets, allowing for greater flexibility in post-acquisition reconstruction while maintaining or improving the signal-to-noise ratio (SNR) compared to Golden ratio-based methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If completely uniform radial sampling is used, then image signal-to-noise ratio (SNR) is optimized, but post-acquisition reconstruction flexibility is lost
Solution Approach 1:
The patent changes the sampling parameter from completely uniform spacing to a modified uniform spacing where the angular increment is adjusted based on the number of radial spokes. This allows the system to maintain good SNR while enabling flexible reconstruction at different temporal resolutions. The angular increment is calculated as 2π/N where N is the number of spokes, creating a sampling pattern that adapts to different reconstruction requirements.
Solution Approach 2:
The sampling scheme transitions from a static completely uniform pattern to a dynamic pattern where the angular increment is determined by the actual number of spokes acquired. This dynamic adaptation allows the same acquired data to be reconstructed at multiple temporal resolutions, providing flexibility without sacrificing SNR performance.
2Adaptability or versatility
If Golden ratio-based sampling is used, then post-acquisition reconstruction flexibility is maintained, but sampling uniformity and image SNR are compromised
Solution Approach 1:
The patent modifies the sampling approach by changing from Golden ratio angular increment to a uniform angular increment based on the number of spokes. This parameter change improves sampling uniformity and consequently enhances image SNR while still maintaining the ability to perform flexible post-acquisition reconstruction at different temporal resolutions.
3Measurement precision
If a fixed number of radial spokes is predetermined, then sampling uniformity can be optimized, but adaptability to different temporal resolutions is reduced
Solution Approach 1:
The patent implements a dynamic sampling scheme where the angular increment is determined by the actual number of radial spokes acquired during the scan, rather than being fixed in advance. This allows the sampling uniformity to be optimized for the actual data acquired while still enabling flexible reconstruction at multiple temporal resolutions, as the uniformity calculation adapts to the actual number of spokes used in each reconstruction window.
Data Source
AI summary
The present disclosure is directed to radially-based magnetic resonance imaging. In any one or more embodiments, the present methods and systems provide that the angular increment between subsequent radial k-space spokes to be sampled to provide the imaging is performed for a predetermined or pre-defined restricted set of reconstruction window sizes (numbers of radial spokes per frame), or limited views, to maximize the uniformity of sampling within the restricted set of window sizes.