1. Department of Radiology, Kyungpook National University Medical Center, Daegu 702-210, Korea.
2. Department of Radiology and Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul 120-752, Korea.
3. Department of Radiology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul 135-720, Korea.
4. Department of Radiology, Bundang CHA Hospital, CHA University College of Medicine, Seongnam 463-712, Korea.
5. Department of Radiology, Dong-A University College of Medicine, Busan 602-715, Korea.
6. Department of Radiology, Chonnam National University Medical School, Gwangju 501-757, Korea.
7. Department of Radiology, Kyungpook National University Hospital, Daegu 700-721, Korea.