Blade-like k-space sampling for MRI motion artifact reduction
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Solution Overview
Problem
Conventional PROPELLER MRI techniques face challenges in maintaining image quality due to significant patient movement during data acquisition, leading to movement artifacts and a decrease in signal-to-noise ratio (SNR) when using partial parallel acquisition (PPA) methods, as the coil calibration data relation is lost before movement correction can be applied.
Innovation Solution
The method involves partial under-sampling of k-space blades by omitting lines only in the boundary regions, using the central region for coil calibration, and applying GRAPPA or GARSE reconstruction to interpolate missing lines, with optional exclusion of coils contributing minimal SNR and use of SVD methods and regularization theory to solve the linear equation system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If partial parallel acquisition (PPA) methods are used to accelerate data acquisition, then acquisition time is reduced, but coil calibration data relation is lost before movement correction can be applied, leading to movement artifacts and decreased image quality
Solution Approach 1:
The patent segments the k-space sampling into different regions: fully sampled central region for coil calibration and undersampled boundary regions for acceleration. This segmentation allows simultaneous achievement of fast acquisition and reliable coil calibration for movement correction.
Solution Approach 2:
The patent performs coil calibration using the fully sampled central region before applying movement correction to the complete blade data. This preliminary calibration action ensures that movement correction can be properly applied, avoiding the loss of calibration data relation that occurs with conventional PPA methods.
2Loss of time
If conventional PPA methods omit k-space lines for acceleration, then acquisition time is reduced, but signal-to-noise ratio (SNR) decreases and image quality deteriorates
Solution Approach 1:
The patent applies different sampling strategies to different regions of k-space: the central region is fully sampled to maintain high SNR and provide accurate coil calibration data, while the boundary regions are undersampled to achieve acceleration. This local quality differentiation resolves the contradiction between speed and image quality.
3Manufacturing precision
If full k-space sampling is performed for each blade to maintain image quality, then signal-to-noise ratio (SNR) is maintained, but acquisition time increases significantly
Solution Approach 1:
The patent applies partial sampling (undersampling) to the boundary regions of k-space while maintaining full sampling in the central region. This partial action approach achieves acceleration without completely sacrificing image quality, as the critical central region remains fully sampled.
Data Source
AI summary
In a data acquisition and reconstruction method for magnetic resonance (MR) tomography, and a corresponding MR tomography apparatus, a blade-like sampling of k-space according to the PROPELLER method using a number of reception coils ensures with partial under-sampling of at least one blade of k-space such that the under-sampling ensues by regular omission of k-space lines in both boundary regions (with regard to the phase-encoding direction ky) of a blade such that only data in each A-th line of said boundary regions are acquired; with no k-space lines being omitted in the central region (with regard to the ky-direction) and thus at least one coil calibration line is obtained, selection of a suitable PPA method for completion of the blades and determination of the necessary coil calibration data necessary for the PPA reconstruction of a partial under-sampled blade from the central completely sampled region of said blade. PPA reconstruction via application of the selected PPA method selected in order to interpolate the non-measured or, respectively, omitted k-space lines of each blade, and execution of the PROPELLER reconstruction after the PPA reconstruction.