From the Department of Radiology, Neuroradiology Section (M.W., W.P.D.), University of California, San Francisco; the Departments of Radiology (V.M., A.Q., S.P.) and Neurology (J.S.), Hospital Doctor Josep Trueta, Girona, Spain; the Departments of Radiology (A.E.F.) and Neurology (C.P.), Thomas Jefferson University Hospital, Philadelphia, Pa; the Department of Radiology (B.V., M.v.L., I.v.d.S., A.W.), University Medical Center Utrecht, The Netherlands; the Departments of Radiology (R.M., P.S.) and... (At 2006-04)