1. From the Neurovascular Research Laboratory, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown (T.S., T.T., T.Q., C.A.)
2. Department of Neurosurgery, Jikei University School of Medicine, Tokyo, Japan (T.S., Y.M.)
3. Department of Neurosurgery, Brain Research Institute, Niigata University, Japan (T.S., Y.F.)
4. Departments of Anesthesia and Perioperative Care, University of California, San Francisco (Y.K.)
5. Department of Neurosurgery and Neurobiology, Barrow Neurological Institute, Phoenix, AZ (T.H.)
6. Department of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, Boston (A.B.P.)
7. Stroke Service, Department of Neurology, Massachusetts General Hospital, Boston (C.A.).