1. From the Departments of Neuroradiology (Michèle Hamon, P.C.), Cardiology (S.G., R.S., T.L., G.G., Martial Hamon), and Statistics (R.M.), University Hospital of Caen, Normandy, France; and the Department of Neuroradiology (C.O.), Sainte-Anne Hospital, Paris Descartes University, Paris, France.