1. Department of Radiology, College of Medicine, The Catholic University of Korea, Seoul 137-701, Korea.
2. Department of Radiology, Seoul National University College of Medicine, Seoul 110-744, Korea.
3. Department of Radiology, Seoul National University Bundang Hospital, Seongnam 463-707, Korea.
4. Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 138-736, Korea.
5. Department of Radiology, Kyung Hee University College of Medicine, Seoul 130-872, Korea.
6. Department of Radiology, Korea University College of Medicine, Seoul 136-705, Korea.
7. Department of Pathology, College of Medicine, The Catholic University of Korea, Seoul 137-701, Korea.
8. Department of Orthopedic Surgery, College of Medicine, The Catholic University of Korea, Seoul 137-701, Korea.