1. From the Neurovascular & Neuroradiology Research Unit, Nuffield Department of Surgical Sciences (A.M., A.C., M.S.) and the Department of Clinical Neurology (Z.M.), University of Oxford, Oxford, UK; the Department of Neuroradiology, Royal Hallamshire Hospital, Sheffield, UK (S.C.); the Department of Radiology, Notre Dame Hospital, Montreal, Canada (D.R.); the Department of Radiology, St Mary's Hospital, Mayo Clinic, Rochester, MN (D.F.K.); and the Department of Neuroradiology, Sunnybrook Health...