1. From the Radiology Department, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, Rua Dr Ovídio Pires de Campos, 225 Cerqueira César, São Paulo, SP 36070-460, Brazil (L.L.d.F., C.P.C., F.A.S.e.V., D.d.C.K., D.Y.O., M.O.F., L.S.); and Department of Radiology, Boston Childrens Hospital, Harvard Medical School, Boston, Mass (M.A.B.).