1. Department of Radiology (K.S., D.Y.C., M.B., P.F., T.T., S.A.A., T.Q., T.Y., F.O., C.A.), Massachusetts General Hospital, Harvard Medical School, Boston.
2. Department of Neurosurgery, Yamaguchi University School of Medicine, Japan (K.S., F.O.).
3. Department of Neurology (D.Y.C., A.H., C.A.), Massachusetts General Hospital, Harvard Medical School, Boston.
4. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown (M.A.Y., S.S.).