From the Department of Radiology, Neuroradiology Division (A.B.D., R.M.d.C., R.L.), and Department of Pathology (E.C., C.S.G.), Irmandade Santa Casa de Misericórdia de Porto Alegre Hospital, Porto Alegre; and Department of Radiology, Neuroradiology Division (L.L.F.d.A.), Medimagem, Beneficência Portuguesa de São Paulo Hospital, Brazil.