1. Hematology Oncology Center National Center for Children's Health Beijing Key Laboratory of Pediatric Hematology Oncology National Key Discipline of Pediatrics, Ministry of Education MOE Key Laboratory of Major Diseases in Children Beijing Children's Hospital Capital Medical University Beijing China
2. Center for Clinical Epidemiology & Evidence‐based Medicine Beijing Children's Hospital National Center for Children's Health Key Laboratory of Major Diseases in Children Ministry of Education Capital Medical University Beijing China
3. Ultrasound Department Beijing Children's Hospital National Center for Children's Health Capital Medical University Beijing China