1. Department of Radiology, Ewha Womans Mokdong Hospital, College of Medicine, Ewha Womans University, Seoul 07985, Republic of Korea
2. Department of Radiology, Ewha Womans Seoul Hospital, College of Medicine, Ewha Womans University, Seoul 07804, Republic of Korea
3. Department of Radiology, Chungnam University Hospital, School of Medicine, Chungnam University, Daejeon 35015, Republic of Korea