1 From the Khoo Teck Puat-National University Children's Medical Institute (C.Y.S.L., N.B.H.N., V.H., K.Y.L., J.B.L.), Department of Paediatrics, National University Health Systems; Department of Paediatrics (N.B.H.N., V.H., K.Y.L., J.B.L.), Yong Loo Lin School of Medicine, National University of Singapore; and Department of Diagnostic Imaging (C.Y.), National University Health System, Singapore.