Diffusion tensor imaging of the brain from patients with primary progressive multiple sclerosis

Introduction. The heterogeneous, pathological processes of multiple sclerosis (MS) have the potential to alter the amount and the organization of structural barriers to water molecular motion, thus determining increased mean diffusion (D) and fractional anisotropy (FA) of the damaged tissue, as measured by diffusion tensor imaging (DTI). Objectives. To quantify tissue damage in patients with primary progressive MS (PPMS) using DTI. Methods. Conventional magnetic resonance (MR) and DTI scans were obtained front 58 PPMS patients and 44 sex- and age-matched healthy controls. After creating D̄ and FA maps, we measured D̄ from the brain, and from normal-appearing white matter (NAWM) and gray matter (NAGM) in isolation using histogram analysis. We also measured FA of lesions and NAWM using regions of interest analysis. Results. Compared to controls, patients with PPMS had higher: (a) average brain D (P