Accelerated Microstructure Imaging via Convex Optimization for regions with multiple fibres (AMICOx)

This paper reviews and extends our previous work to enable fast ax- onal diameter mapping from diffusion MRI data in the presence of multiple fibre populations within a voxel. Most of the existing mi- crostructure imaging techniques use non-linear algorithms to fit their data models and consequently, they are computationally expensive and usually slow. Moreover, most of them assume a single axon ori- entation while numerous regions of the brain actually present more complex configurations, e.g. fiber crossing. We present a flexible framework, based on convex optimisation, that enables fast and ac- curate reconstructions of the microstructure organisation, not lim- ited to areas where the white matter is coherently oriented. We show through numerical simulations the ability of our method to correctly estimate the microstructure features (mean axon diameter and intra- cellular volume fraction) in crossing regions.