Osteoradionecrosis of the hyoid bone after intra-arterial chemoradiotherapy for oropharyngeal cancer: MR imaging findings

BACKGROUND Osteoradionecrosis (ORN) of the hyoid bone sometimes induces severe front neck infection and can cause laryngeal stenosis and carotid rupture. Although ORN of the hyoid bone is known to be a complication of chemoradiotherapy for head and neck cancer, there has been no basis for its evaluation. Our purpose is to present the clinical and MR imaging features of ORN of the hyoid bone. METHODS The study group comprised patients with advanced oropharyngeal cancer treated with targeted intra-arterial cisplatin infusion with concomitant radiotherapy. ORN of the hyoid bone was identified on the basis of decreased signal intensity of the bone marrow on T1WI images. Signal intensity on T2WI images was used to distinguish between inflammation and fibrosis. RESULTS A total of 39 pre-treatment MR images and follow-up MR images were reviewed. ORN of the hyoid bone were detected in 30% of patients after treatment, with 23% of them showing inflammation and 7.7% fibrosis. Two patients developed severe neck infection and received antibiotics and underwent surgical intervention by tracheostomy and resection of the hyoid bone. CONCLUSION Our MR imaging study showed that ORN of the hyoid bone is not particularly rare in patients with oropharyngeal cancer treated with chemoradiotherapy. Clinicians should evaluate images carefully to prevent the development of severe complication due to infection associated with ORN of the hyoid bone.