Dynamic MR imaging of mandibular osteoradionecrosis

metabolically inactive tissue with impaired perfusion. The present study wa s conducted to determine if dynamic contrast-enhanced MR imaging could prov ide additional information about the vascularity of radionecrotic mandibula r bone. Material and Methods: Dynamic contrast-enhanced MR imaging was performed on 10 patients with mandibular osteoradionecrosis (ORN), and on 6 patients, i rradiated for oropharyngeal tumours, without symptoms or signs of ORN. Nine patients in the ORN group received a series of 20 hyperbaric oxygen (HBO) treatments, after which the dynamic MR investigation was repeated. Results and Conclusion. Radiation per se did not lead to increased contrast enhancement, whereas all patients with ORN showed marked contrast enhancem ent of the osteoradionecrotic bone marrow. After HBO treatment, pathologica l contrast enhancement of the abnormal bone marrow could still be seen, but the rate of enhancement was less than before in 7 of 9 patients. Two patie nts had an increase in the enhancement rate. The findings suggest the exist ence of an increased and patent microvasculature.