1. Department of Radiology, Soonchunhyang University Gumi Hospital, Gumi 730-706, Korea.
2. Department of Obstetrics and Gynecology, Soonchunhyang University Gumi Hospital, Gumi 730-706, Korea.
3. Department of Radiology, Soonchunhyang University Hospital, Seoul 140-743, Korea.
4. Department of Radiology, Chosun University Hospital, Gwangju 501-717, Korea.