Improved B0 -distortion correction in diffusion MRI using interlaced q-space sampling and constrained reconstruction.
OBJECTIVE
To enable high-quality correction of susceptibility-induced geometric distortion artifacts in diffusion magnetic resonance imaging (MRI) images without increasing scan time.


METHODS
A new method for distortion correction is proposed based on subsampling a generalized version of the state-of-the-art reversed-gradient distortion correction method. Rather than acquire each q-space sample multiple times with different distortions (as in the conventional reversed-gradient method), we sample each q-space point once with an interlaced sampling scheme that measures different distortions at different q-space locations. Distortion correction is achieved using a novel constrained reconstruction formulation that leverages the smoothness of diffusion data in q-space.


RESULTS
The effectiveness of the proposed method is demonstrated with simulated and in vivo diffusion MRI data. The proposed method is substantially faster than the reversed-gradient method, and can also provide smaller intensity errors in the corrected images and smaller errors in derived quantitative diffusion parameters.


CONCLUSIONS
The proposed method enables state-of-the-art distortion correction performance without increasing data acquisition time.
Signal and Image Processing Institute, Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California, USA.
Chitresh
C
Bhushan
Anand A
AA
Joshi
Richard M
RM
Leahy
Justin P
JP
Haldar
D000465:Algorithms; D016477:Artifacts; D001931:Brain Mapping / Q000379:methods*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D017352:Echo-Planar Imaging; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods*
B0-field inhomogeneity; constrained reconstruction; diffusion magnetic resonance imaging; distortion correction; echo-planar imaging; interlaced q-space sampling