I. Introduction
Quantitative characterization of the white matter (WM) circuitry in the human brain is paramount for mapping the structural connectome, which is known to be affected by neurological diseases. Diffusion magnetic resonance imaging (DMRI) can describe this circuitry in vivo by measuring variations in water diffusion along several directions. In particular, these measurements provide insights into the mathematical representations of diffusion (e.g., diffusion tensors (DTs) [1], higher order tensors [2], orientation distribution functions (ODFs) [3]), which reflect the local fiber orientation profile. These representations can be used to extract a tractogram, i.e., WM fiber pathways given by tractography.