1. Department of Radiology, Tokyo Dental College Ichikawa General Hospital, Chiba, Japan
2. Department of Oral and Maxillofacial Radiology, Tokyo Dental College, Tokyo, Japan
3. Department of Radiology, Jikei University School of Medicine, Tokyo, Japan
4. Laboratory of Mathematics, Tokyo Dental College, Tokyo, Japan
5. Department of Oral and Maxillofacial Surgery, Tokyo Dental College Ichikawa General Hospital, Ichikawa, Chiba, Japan