From the Stroke Service, Neurology Service (U.C., K.L.F., N.S., F.S.B., W.J.K., J.P.K.); the Department of Pathology (J.F.S.); the Vascular Laboratory (N.R.M.); and the Neurosurgery Service (C.S.O.), Massachusetts General Hospital, Boston, Mass. (1997-10時点)