Phase Correction for Three-Dimensional (3D) Diffusion-Weighted Interleaved EPI Using 3D Multiplexed Sensitivity Encoding and Reconstruction (3D-MUSER)

Abstract

Purpose Three‐dimensional (3D) multiplexed sensitivity encoding and reconstruction (3D‐MUSER) algorithm is proposed to reduce aliasing artifacts and signal corruption caused by inter‐shot 3D phase variations in 3D diffusion‐weighted echo planar imaging (DW‐EPI).

Theory and Methods 3D‐MUSER extends the original framework of multiplexed sensitivity encoding (MUSE) to a hybrid k‐space‐based reconstruction, thereby enabling the correction of inter‐shot 3D phase variations. A 3D single‐shot EPI navigator echo was used to measure inter‐shot 3D phase variations. The performance of 3D‐MUSER was evaluated by analyses of point‐spread function (PSF), signal‐to‐noise ratio (SNR), and artifact levels. The efficacy of phase correction using 3D‐MUSER for different slab thicknesses and b‐values were investigated.

Results Simulations showed that 3D‐MUSER could eliminate artifacts because of through‐slab phase variation and reduce noise amplification because of SENSE reconstruction. All aliasing artifacts and signal corruption in 3D interleaved DW‐EPI acquired with different slab thicknesses and b‐values were reduced by our new algorithm. A near‐whole brain single‐slab 3D DTI with 1.3‐mm isotropic voxel acquired at 1.5T was successfully demonstrated.

Conclusion 3D phase correction for 3D interleaved DW‐EPI data is made possible by 3D‐MUSER, thereby improving feasible slab thickness and maximum feasible b‐value. Magn Reson Med 79:2702–2712, 2018. © 2017 International Society for Magnetic Resonance in Medicine.