1. From the Department of Pediatrics, Boston Children’s Hospital (S.A.K., J.S.H.), the Departments of Pediatrics (M.M.L.), Radiology (S.J.W.), Medicine (J.S.H.), and Pathology (S.B.M.), Massachusetts General Hospital, and the Departments of Pediatrics (M.M.L.), Radiology (S.J.W.), Medicine (J.S.H.), and Pathology (S.B.M.), Harvard Medical School — all in Boston.