1. From the Departments of Diagnostic Imaging (E.J.I.C., M.N., M.R.P.), Pathology (M.S.C.), and Maxillary and Oral Surgery (J.R.P., A.A.C.), Hospital Sant Joan de Deu, Av. Sant Joan de Deu 2, CP 08950 Esplugues de Llobregat (Barcelona), Spain; and Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario, Canada (M.T.).