1. Department of Otolaryngology Head and Neck Surgery, The Second Hospital of Baoding, Baoding 071000, China
2. Department of Obstetrics, Affiliated Hospital of Hebei University, Baoding 071000, China
3. Department of Radiology, Affiliated Hospital of Hebei University, Baoding 071000, China
4. Department of MR Room, Qingyuan District People’’s Hospital, Baoding 071000, China