1. Department of Obstetrics and Gynecology, Dongguk University College of Medicine, Seoul, Korea.
2. Department of Pathology, Dongguk University College of Medicine, Seoul, Korea.
3. Department of Radiology, Dongguk University College of Medicine, Seoul, Korea.
4. Department of Obstetrics and Gynecology, Chung-Ang University College of Medicine, Seoul, Korea.