1. Department of Radiology, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Republic of Korea
2. Department of Radiology, Seoul National University Hospital, Seoul National University College of Medicine, 101 Daehangno, Jongno-gu, Seoul, 110-744, Republic of Korea
3. Department of Radiology, Soonchunhyang University Bucheon Hospital, Bucheon, Republic of Korea
4. Department of Radiology, Korea University Guro Hospital, Seoul, Republic of Korea
5. Department of Radiology, Chung-Ang University Hospital, Seoul, Republic of Korea