1. Department of Pediatrics, The First Affiliated Hospital of Harbin Medical University, Harbin 150001, P.R. China
2. Department of Ultrasound Medicine, The Fifth Hospital of Harbin, Harbin 150040, P.R. China
3. Department of Neurosurgery, Tieling Central Hospital, Tieling 112000, P.R. China
4. Department of Stomatology, The Fourth Affiliated Hospital of Harbin Medical University, Harbin 150001, P.R. China
5. Department of Pediatrics, The First Hospital of Jilin University, Changchun 130021, P.R. China