1. Department of Otorhinolaryngology-Head and Neck Surgery, Seoul, Korea
2. Konkuk University School of Medicine, and the Department of Radiology, Soonchunhyang University College of Medicine, Seoul, Korea
3. BK21 Project for Medical Science, Seoul, Korea
4. Dept of Otorhinolaryngology-Head and Neck Surgery, School of Medicine, Konkuk University, 4–12 Hwayang-dong, Gwangjin-gu, Seoul, 143–729, Korea