Investigating white matter fibre density and morphology using fixel-based analysis

Voxel-based analysis of diffusion MRI data is increasingly popular. However, most white matter voxels contain contributions from multiple fibre populations (often referred to as crossing fibres), and therefore voxel-averaged quantitative measures (e.g. fractional anisotropy) are not fibre-specific and have poor interpretability. Using higher-order diffusion models, parameters related to fibre density can be extracted for individual fibre populations within each voxel ('fixels'), and recent advances in statistics enable the multi-subject analysis of such data. However, investigating within-voxel microscopic fibre density alone does not account for macroscopic differences in the white matter morphology (e.g. the…

• W
  Wellcome

  Award: 091593/Z/10/Z
• WT
  Wellcome Trust

  Award: 091593/Z/10/Z
• SG
  State Government of Victoria
• MR
  Medical Research Council

  Awards: MR/J014257/2, MR/J014257/2
• NH
  National Health and Medical Research Council

  Award: 400121