Right-angle demyelination in multiple sclerosis

MR imaging has been demonstrated to be a highly sensitive but relatively nonspecific test for white matter disease (WMD). The author have observed in multiple sclerosis (MS) patients a white matter lesion oriented perpendicular to the ventricular system, which we call right angle demyelination (RAD), corresponding anatomically with perivenular plaques (Dawson fingers) which have not been noted pathologically in other WMD. The author retrospectively reviewed cases of 29 consecutive patients with WMD for RAD and for clinical evidence of MS using TR 2,000/TE40, 5-mm contiguous axial and coronal scans. Sixteen had definite clinical MS and 12 had RAD (sensitivity, 75%). Thirteen did not have clinical MS, and six had RAD (specificity, 54%)