Quantification of white matter pathologies by a diffusion MRI technique modeling both intra- and extra-axonal compartments

A new diffusion MRI histology (D-Histo) is proposed to model both intra- and extra-axonal diffusion as well as isotropic diffusion components within an image voxel. Both Monte-Carlo simulation, in vivo MRI of EAE mouse optic nerve, and post-MRI histology were used to validate this approach. The intra-axonal fraction derived from D-Histo more accurately assessed fiber fraction, and the intra-axonal axial diffusivities (AD) it derives more sensitively reflected axonal injury.