1 Department of Respiratory Medicine, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China.
2 Department of Radiology, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China.
3 Department of Pathology, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China.
4 Department of Respiratory Medicine, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China. Electronic address: zhaoshunying2001@163.com.