Improved Microstructure-Informed Myelin Mapping (iMIMM) for Myelin Mapping solely from Gradient-Echo Data

Motivation: Recently, microstructure-informed myelin mapping (MIMM) was proposed to estimate myelin content from multi gradient-echo (mGRE) data by modeling both magnitude and phase-derived susceptibility values. Although magnitude modeling incorporated the susceptibility anisotropy, susceptibility modeling ignored it. Goal(s): Here, MIMoSA is proposed to improve upon MIMM by including the susceptibility anisotropy both in magnitude and phase. Approach: Following MIMM, a dictionary of voxel signals associated with specific microstructures including myelin and iron was generated with a novel negative susceptibility estimation approach. Results: In vivo results of healthy subjects showed that iMIMM performs similar with MIMM without the need of an additional orientation prior. Impact: By accurate modeling of the effect of white matter anisotropic susceptibility on the full gradient-echo signal, myelin content can be mapped from routine gradient echo acquisitions.