Abstract #2094

Chen J, Atkins H, Collins D, Arnold D, Freedman M

Subpial demyelinating lesions in multiple sclerosis are generally undetectable by conventional MRI in vivo, despite the high prevalence of extensive cortical lesional pathology on post-mortem examinations. We used T1-weighted MRI to define the boundary between cerebrospinal-fluid and cortex, and magnetization transfer ratio images to define a boundary between sparsely myelinated and normally myelinated cortex. This allowed the detection of abnormal regions of subpial demyelination extending into the deeper layers of the cortex with a pattern and prevalence consistent with cortical subpial demyelinating lesions.