1. Department of Radiology, Kanazawa Medical University, Daigaku 1-1, Uchinada, Kahoku, Ishikawa 920-0293, Japan.
2. Department of Head and Neck Surgery, Kanazawa Medical University, Kahoku, Ishikawa, Japan.
3. Department of Medical Technology, Kanazawa Medical University, Kahoku, Ishikawa, Japan.