Global estimation of anatomical connection strength in diffusion MRI tractography by message-passing

This paper addresses an important problem in diffusion weighted MRI tractography -the estimation of the anatomical strength of reconstructed neuronal fibers. Our method incorporates information on the amount of white matter in voxels (small areas of brain) with diffusion data and estimates structural strength of fibers globally, by considering all the fibers and all the voxels simultaneously. We achieve this by using a message-passing optimization procedure, specially tailored for this problem, that operates on a bipartite graph with nodes corresponding to fibers and voxels. New estimates of fiber strength allow derivation of new measures for quantifying anatomical connections between large gray matter regions. In this paper we propose two: Anatomical Connection Weight (ACW) and Normalized Connection Weight (NCW). The proposed methodology was applied on human data and tested for convergence and consistency.