1. Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul 138-736, Korea.
2. Department of Otorhinolaryngology, University of Ulsan College of Medicine, Asan Medical Center, Seoul 138-736, Korea.
3. Department of Pathology, University of Ulsan College of Medicine, Asan Medical Center, Seoul 138-736, Korea.