Osteoradionecrosis of the upper cervical spine after radiation therapy for head and neck cancer: differentiation from recurrent or metastatic disease with MR imaging.

PURPOSE

To compare the magnetic resonance (MR) imaging features of upper cervical spine osteoradionecrosis (ORN) with those of recurrent or metastatic disease after the treatment of head and neck malignancies.

MATERIALS AND METHODS

This retrospective study was approved by the hospital institutional review board, and the requirement to obtain informed consent was waived. From January 2005 to December 2010, 35 patients who had undergone irradiation of head and neck cancer and who had subsequent C1 or C2 lesions at MR imaging were enrolled. Pathology reports, clinical records, and follow-up MR images were reviewed to classify patients into one of two groups-those with ORN or those with recurrence. The MR imaging characteristics in these patients were evaluated. Statistical significance of intergroup differences was assessed by means of the Pearson χ2 or Fisher exact test for categorical variables and the two-sample t test for continuous variables.

RESULTS

ORN was diagnosed in 20 of the 35 patients (57%), and recurrent or metastatic disease was diagnosed in 15 (43%). Ten of the 35 patients (29%) had undergone biopsy of the cervical spine or paraspinal soft tissue. The MR images in the ORN group showed significantly more contiguous involvement of the atlantoaxial or atlanto-occipital bones with intervening joint change (P<.001), more cases of vertebral body collapse (P<.01), more bilateral symmetric involvement of the vertebral body (P<.01), and continuation of vertebral body changes with posterior pharyngeal wall ulceration (P<.01). Posterior arch or other cervical level involvement, paraspinal solid mass, epidural involvement, lateral border cortical destruction, and cervical lymphadenopathy were noted more frequently in the recurrence group than in the ORN group (P=.03, P<.001, P=.02, P<.001, and P<.01, respectively).

CONCLUSION

Various MR imaging characteristics can be used to help differentiate between cervical ORN and recurrent disease.