1. Department of Otolaryngology, Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, PR China;
2. Department of Otolaryngology, Head and Neck Surgery, General Hospital of Ningxia Medical University, Yinchuan, PR China;
3. Division of Pulmonary and Critical Care Medicine La Jolla, University of California at San Diego, Sandiego, CA, USA;
4. Department of Radiology, Beijing Tongren Hospital, Capital Medical University, Beijing, PR China;
5. Department of Otolaryngology, Head and Neck Surgery, Beijing Tsinghua Chang Gung Hospital, Beijing, PR China;
6. Department of Otolaryngology, Head and Neck Surgery, Peking University First Hospital, Beijing, PR China