Abstract: Objective: To evaluate the imaging features of osteoradionecrosis of the jaws secondary to treatment of head and neck malignancy. Methods: We retrospectively reviewed clinical and imaging data of 68 patients with osteoradionecrosis of the jaws, including the type and site of primary tumors, the interval between the completion of radiotherapy and onset of osteoradionecrosis, imaging findings of the involved mandible or maxilla, postoperative pathological diagnosis. Results: Primary tumors were mostly nasopharyngeal carcinoma and oral cancer. The majority of osteoradionecrosis was involved in the body or body-ramus of the mandible (63 cases, 91.18%). Forty-nine cases (72.06%) of osteoradionecrosis were diagnosed within 5 years after radiotherapy. Loss or disorganization of trabecula and interruption of the cortical margin were observed in nearly all cases (89.7% and 77.94%, respectively), followed by sequestrum (42.65%) and bony sclerosis (33.82%), and soft tissue or muscle thickening adjacent to the affected bone in 6 cases. Conclusion: CT findings provide more reliable diagnostic tools for osteoradionecrosis of the jaws, and are able to determine the extent of involved bone and helpful to differentiate from tumor recurrence.

Key words: Osteoradionecrosis, Head and neck, Malignancy