1. Department of Radiology, St. Vincent's Hospital, College of Medicine, The Catholic University of Korea, Suwon, Korea.
2. Department of Radiology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
3. Department of Radiology, Daejeon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Daejeon, Korea.
4. Department of Radiology, National Cancer Center, Goyang, Korea.