1. Department of Gynaecology, The Second Hospital of Shandong University, Jinan, Shandong 250033, P.R. China
2. Department of Obstetrics and Gynecology, Zhangqiu Maternity and Child Care Hospital, Jinan, Shandong 250200, P.R. China
3. Department of Imaging, People's Hospital of Rizhao, Rizhao, Shandong 276800, P.R. China
4. Ward Department, The People's Hospital of Zhangqiu Area, Jinan, Shandong 250200, P.R. China
5. Department of Radiology, The People's Hospital of Zhangqiu Area, Jinan, Shandong 250200, P.R. China
6. Department of Interventional Medicine, The Second Hospital of Shandong University, Jinan, Shandong 250033, P.R. China