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Intravoxel B 0 inhomogeneity corrected reconstruction using a low‐rank encoding operator
Author(s) -
Lam Fan,
Sutton Bradley P.
Publication year - 2020
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.28182
Subject(s) - computer science , undersampling , algorithm , intravoxel incoherent motion , regularization (linguistics) , computation , operator (biology) , encoding (memory) , piecewise , iterative reconstruction , inverse problem , mathematical optimization , artificial intelligence , mathematics , diffusion mri , mathematical analysis , magnetic resonance imaging , medicine , biochemistry , chemistry , repressor , transcription factor , gene , radiology
Purpose To present a general and efficient method for macroscopic intravoxel B 0 inhomogeneity corrected reconstruction from multi‐TE acquisitions. Theory and Methods A signal encoding model for multi‐TE gradient echo (GRE) acquisitions that incorporates 3D intravoxel B 0 field variations is derived, and a low‐rank approximation to the encoding operator is introduced under piecewise linear B 0 assumption. The low‐rank approximation enables very efficient computation and memory usage, and allows the proposed signal model to be integrated into general inverse problem formulations that are compatible with multi‐coil and undersampling acquisitions as well as different regularization functions. Results Experimental multi‐echo GRE data were acquired to evaluate the proposed method. Effective reduction of macroscopic intravoxel B 0 inhomogeneity induced artifacts was demonstrated. Improved R 2 ∗ estimation from the corrected reconstruction over standard Fourier reconstruction has also been obtained. Conclusions The proposed method can effectively correct the effects of intravoxel B 0 inhomogeneity, and can be useful for various imaging applications involving GRE‐based acquisitions, including fMRI, quantitative R 2 ∗ and susceptibility mapping, and MR spectroscopic imaging.