1. From the Departments of Radiology and Neurology, Stanford Stroke Center, CA (M.P.M., J.J.H., M.G.L., S.K., S.C., S.H., M.M., G.W.A.)
2. Department of Radiology, University of Iowa (C.P.D.)
3. Department of Neurological Surgery and the Cerebrovascular Center, Cleveland Clinic, OH (P.A.R.)
4. Department of Neurosurgery, Mercy Health, Toledo, OH (O.O.Z.)
5. Department of Neurology, University of Cincinnati, OH (J.P.B.)
6. Department of Public Health Sciences, Medical University of South Carolina, Charleston (S.D.Y.).