1. Department of Gynecology, Chongqing Haifu Hospital, Chongqing, P.R. China
2. State Key Laboratory of Ultrasound in Medicine and Engineering, College of Biomedical Engineering, Chongqing Medical University, Chongqing, P.R. China
3. Department of Gynaecology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizou, P.R. China