1. From the Department of Medicine, University of California, San Francisco, San Francisco (S.A.C.); and the Departments of Radiology (A.J.H.), Medicine (M.R.M., Z.S.W.), Neurology (B.K.C.), and Pathology (M.R.M., L.N.K.), Massachusetts General Hospital, and the Departments of Radiology (A.J.H.), Medicine (M.R.M., Z.S.W.), Neurology (B.K.C.), and Pathology (M.R.M., L.N.K.), Harvard Medical School — both in Boston.