1. Department of Radiology, SMG-SNU Boramae Medical Center, Seoul National University College of Medicine, Seoul, Korea.
2. Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
3. Department of Radiology, The Catholic University of Korea, Eunpyeong St. Mary's Hospital, Seoul, Korea.
4. Department of Radiology, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Korea.