1. Department of Radiology, Seoul National University Hospital, Seoul, Korea.
2. Department of Radiology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
3. Department of Radiology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Korea.
4. Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea.
5. Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
6. Department of Radiology, Seoul National University College of Medicine, Seoul, Korea.
7. Department of Radiology, Eunpyeong St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
8. Department of Radiology, Yonsei University College of Medicine, Seoul, Korea.
9. Department of Radiology, Korea University Guro Hospital, Seoul, Korea.