1. From the Division of Neuroimaging and Neurointervention, Department of Radiology (J.J.H., M.P.M.)
2. Department of Neurology and Neurological Sciences (M.M., S.M.K., M.G.L., S.C., G.W.A.), Stanford University School of Medicine, CA
3. Department of Neurology, Radiology, and Neurosurgery, University of Iowa, Iowa City (S.O.-G.).