Estimated fODF in the corpus callosum in a patient. As part of the initial qualitative assessment, we looked at the number of peaks at a WM lesion at the boundaries of the corpus callosum, where it is known there are fibres with a similar orientation. Panel (a) shows a coronal view of a T1-weighted image of a patient with a (T1-hypointense) lesion in the confluence of the corpus callosum and the corticospinal tract; (b) and (c): voxel-wise fODF mapping inside the lesion (lesion mask overlaid), obtained with the single-shell single-tissue (b) and multi-shell multi-tissue (c) algorithms; (d) and (e): fODF within a lesional voxel belonging to WM tissue known to have only one fibre population, for each algorithm; whereas (e) (multi-shell multi-tissue algorithm) shows no spurious peaks, these are observed in (d) (single-shell singletissue). The reduced size of the fODF in (e) reflects the partial volume effects within the lesion. fODF: fibre orientation distribution function; WM: white matter.