1. Department of Otolaryngology‐Head and Neck Surgery Tohoku University Hospital Sendai Japan
2. Head and Neck Cancer Center Tohoku University Hospital Sendai Japan
3. Department of Oral Diagnosis Tohoku University Hospital Sendai Japan
4. Department of Diagnostic Radiology Tohoku University Hospital Sendai Japan
5. Department of Neurosurgery Tohoku University Hospital Sendai Japan
6. Department of Pathology Tohoku University Hospital Sendai Japan