Diffusion MRI-based cortical complexity alterations associated with executive function in multiple sclerosis.

Purpose: To report a novel magnetic resonance imaging measure (diffusion orientational complexity [DOC]) in a study of people with multiple sclerosis (MS) and healthy controls and to determine patterns of abnormality, correlations with conventional diffusion measures, and associations with cognitive function. Materials and Methods: We performed high angular resolution diffusion imaging (HARDI) and measured DOC, mean diffusivity (MD), and fractional anisotropy (FA) in 51 MS patients and 28 healthy controls. All subjects had a 2-mm isotropic HARDI scan on a 3 T scanner using a 32-channel head receiver coil. DOC, MD, and FA were measured in three regions of interest (ROIs) in frontal cortex li…