In Vivo Myelin Water Imaging Using 3d Multi-gradient-echo Pulse Sequences

Introduction. Quantitative imaging of the myelin water fraction (MWF) is able to show demyelinating processes and therefore provides insight into the pathology of white matter (WM) diseases such as multiple sclerosis. So far, mapping of the MWF most often was performed using single-slice multi-echo spin-echo sequences (1). Lately, a different approach, using multi-gradient-echo pulse sequences, was introduced by one study measuring formalin-fixed brains (2) and has been adapted to in vivo measurements by different groups since then (3,4). In this work, we present a solution for 3D in vivo myelin water imaging with whole brain coverage by applying multi-gradient-echo pulse sequences and using a non-negative least squares (NNLS) algorithm to analyze the T2 decay.