1 From the Departments of Neurology (B.K.C., A.W.F.), Radiology (H.R.K.), Psychiatry (A.W.F.), Medicine (A.M.J., M.R.M.), and Pathology (M.R.M.), Massachusetts General Hospital, the Departments of Neurology (B.K.C., A.W.F.), Radiology (H.R.K.), Psychiatry (A.W.F.), Medicine (A.M.J., M.R.M.), and Pathology (M.R.M.), Harvard Medical School, and the Department of Radiology, Massachusetts Eye and Ear (H.R.K.) - all in Boston.