Aim: To evaluate the computed tomography (CT) and magnetic resonance imaging (MRI) findings of biphosphonate therapy-associated changes of the mandible and maxilla.
Materials and methods: Thirty-two patients with a clinical history of pain, purulent discharge, and swelling in the mandible or maxilla as well as non-healing dental extraction were examined. All patients had received biphosphonate medication for approximately 33 months. Non-contrast enhanced CT and contrast-enhanced MRI were performed and, subsequently, all patients underwent a surgical removal of the affected bone, the histological diagnosis of which confirmed osteonecrosis. The images were read by two head and neck radiologists in consensus.
Results: Osteonecrosis with Actinomyces infection was identified in the mandible of 18 patients, in the maxilla of eight patients, and in both jaws in six patients. The CT images showed predominantly osteolytic lesions and sclerotic regions in the jaws with or without periostal bone proliferation. There was a reduction of the marrow space in the jaws. The T1-weighted MRI signal was hypointense in nearly all cases. The gadolinium-enhanced MRI images revealed intensity changes of the cortical and subcortical bone structures in all patients. The T2-weighted MRI signal was hypointense on the affected side in the majority of the cases (28/32). Pathological gadolinium enhancement was observed in the neighbouring soft tissues, including the masticator space in all patients. Reactive lymphadenopathy was found in all patients in submental and jugulodigastric areas.
Conclusion: Biphosphonate-induced osteonecrosis of the jaws presents a wide variety of CT and MRI features that are readily recognized and help to determine the extent of the disease; however, they are not specific for the disease.