1. Department of Thyroid and Parathyroid Surgery, West China Hospital, Sichuan University, Chengdu, Sichuan, P.R. China
2. Department of Ultrasound, West China Hospital, Sichuan University, Chengdu, Sichuan, P.R. China
3. Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, P.R. China