1. Department of Neonatology, Saitama Children's Medical Center, Saitama, Saitama, Japan
2. Department of Pediatrics, Saitama Medical Center, Saitama Medical University, Kawagoe, Saitama, Japan
3. Department of Radiology, Saitama Children's Medical Center, Saitama, Saitama, Japan
4. Department of Pediatric Surgery, Saitama Children's Medical Center, Saitama, Saitama, Japan
5. Department of Pediatric Surgery, The University of Tokyo Hospital, Bunkyo-ku, Tokyo, Japan