Imaging of mandibular osteoradionecrosis

Mandibular osteoradionecrosis (ORN) is a rare, but potentially severe, complication of radiotherapy for head and neck neoplasms. The diagnosis is essentially based on history and clinical findings, but patients are often referred for imaging to confirm the diagnosis, to map the disease extent for management purposes, and to exclude malignant disease. The imaging features in mandibular ORN, as seen on conventional radiographic, CT, and MR imaging studies, are reviewed. Bone abnormalities in mandibular ORN are often associated with a soft tissue mass, making the CT and MR imaging differential diagnosis with tumor recurrence difficult. Some findings, however, such as the association with cortical defects away from the position of the original tumor (at the buccal surface or in the heterolateral side of mandible), make the diagnosis of mandibular ORN more likely.