1. From the Mallinckrodt Institute of Radiology (M.S.G., K.D.V., T.B., C.P.D., J.-M.L.), Department of Neurology (R.W., C.P.D., J.-M.L., A.L.F.), Division of Emergency Medicine (L.H., P.P.), and Department of Neurological Surgery (C.P.D.), Washington University School of Medicine, St Louis, MO; Department of Operational Excellence (B.G.H.) and Department of Emergency Services (J.W.), Barnes-Jewish Hospital, St Louis, MO; Department of Neuroradiology, University of Montreal, Montreal, Quebec, Canada (N...