Efficient T2 and diffusion weighted imaging using the multiple-echo steady-state (MESS) sequence with a 3D PROPELLER acquisition

Motivation: The multiple-echo steady-state (MESS) sequence extends double-echo steady state and efficiently measures multiple images with different contrasts. Because diffusion contrasts are important in clinical imaging, this study aims to include strong diffusion weighting in the MESS sequence. Goal(s): To extend the MESS sequence to provide distortion-free, high-resolution 3D T1-, T2- and diffusion-weighted imaging. Approach: The DW-MESS sequence utilizes a 3D EPI-PROPELLER acquisition to acquire 32 echoes per repetition. An incoherent non-Cartesian k-space trajectory enables reconstruction of individual echoes. Results: The DW-MESS images show contrasts comparable to SE-EPI with anterior-posterior diffusion encoding. Artifacts are present in other diffusion directions, and require further phase corrections. Impact: This study enables stronger diffusion-weighting in DESS-type sequences in addition to T1- and T2-weighting. The incoherent k-space trajectory allows reconstruction of a B0-map and coil-sensitivities, and could allow T2* and susceptibility quantification. This provides new opportunities for efficient multi-parametric imaging.