1. Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710, Korea.
2. Joeun Madi Hospital, Seoul 130-032, Korea.
3. Department of Radiology, Soonchunhyang University Bucheon Hospital, Bucheon 420-767, Korea.
4. Department of Orthopedic Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710, Korea.