1. Department of Radiology, Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul, Korea

2. Department of Otorhinolaryngology-Head and Neck Surgery, Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul, Korea

3. Department of Radiology, Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul, Korea; Department of Radiology, Hanyang University Hospital, Hanyang University College of Medicine, Seoul, Korea