1. From the Department of Neuroradiology, Hôpital Maison-Blanche, Université Reims-Champagne-Ardenne, Reims, France (L.P., S.S., A.B.); and Division Neuroimaging and Intervention, Departments of Radiology, Neurology, and Neurosurgery, University of Massachusetts Medical School, Worcester (A.K.W.).