Akira Baba1, Hiroya Ojiri2, Shinichi Takahashi3, Akira Katakura4. 1. Department of Radiology, Tokyo Dental College, Ichikawa General Hospital, Chiba, Japan. 2. Department of Radiology, The Jikei University School of Medicine and University Hospital, Tokyo, Japan. 3. Department of Dermatology, Tokyo Dental College, Ichikawa General Hospital, Chiba, Japan. 4. Department of Oral Pathobiological Science and Surgery, Tokyo Dental College, Tokyo, Japan.