Fig 1. Average of 12 coregistered axial SPGR (A) and FLAIR (B) MR images demonstrate cortical MS lesions in patient 3. Several Type B cortical lesions traverse the gray-white boundary (white arrowheads, A, B). A single Type A lesion (white arrows A, B) is confined to the gray matter of the motor strip. Serial magnified images of the precentral gyrus (C-J) conform that this lesion (white arrows D-H) does not extend into the juxtacortical white matter.