MORSE-PI – Flexible and artefact-free image reconstruction for structural and functional QSM and other phase-critical imaging applications.

Motivation: We address the issue of phase singularities and artefacts in phase-critical imaging applications, such as QSM, especially in more complicated scenarios: 7T, under-sampled, or single-echo scans. Goal(s): To develop an image reconstruction method, “MORSE-PI”, that provides high SNR, artefact-free and singularity-free phase for structural and functional brain imaging. Approach: MORSE-PI extends our previous approach, MORSE-CODE, by adding a Virtual Reference Coil computation that is used to correct phase offsets in the MORSE-CODE sensitivity estimates. Results: MORSE-PI reconstructs structural and functional brain images at 3T and 7T free from artefacts and phase singularities yielding high SNR QSM. Impact: MORSE-PI flexibly provides high SNR, fold-over-free and singularity-free phase images for single-echo and multi-echo structural GRE and functional EPI scans with real-time reconstruction. MORSE-PI naturally lends itself to phase-based imaging techniques such as structural and functional QSM.