1. From the Biomedical Research Imaging Center and Departments of Radiology (H.A., Y.C., W.L.), Biostatistics (H.Z.), and Neurology (W.J.P., W.L.), University of North Carolina at Chapel Hill; Department of Neurology (A.L.F., G.K., N.K., J.-M.L.), Department of Radiology (R.P., K.D.V., C.P.D., J.-M.L.), Department of Emergency Medicine (P.P.), and School of Medicine (A.L.F., G.K., N.K., J.-M.L., R.P., K.D.V., C.P.D., J.-M.L., A.M.S., P.P.), Washington University, St. Louis, MO; and Emergency Department...