CT findings in temporal bone osteoradionecrosis

Purpose: The goal of this study was to describe computed tomographic findings in patients with clinically proven temporal bone (TB) osteoradionecrosis (ORN) (TB-ORN).

Materials and Methods: Computed tomographic scans of 20 patients were retrospectively evaluated for bony and soft tissue abnormalities. Clinical severity was graded based on level of therapy administered: mild (observation), moderate (antibiotics/hyperbaric oxygen), or severe (surgery).

Results: Radiation dose to the primary tumor ranged from 30 to 75.6 Gy. Time to onset of ORN from completion of radiation therapy was 2 to 22 years (median, 7 years). Clinical findings: exposed bone, 20 of the 20 patients; otorrhea, 17 of the 20 patients; hearing loss, 11 of the 20 patients; otalgia, 10 of the 20 patients; facial nerve paralysis, 2 of the 20 patients; gait imbalance, 2 of the 20 patients. Computed tomographic findings: external auditory canal erosions, 18 of the 20 patients; mastoid effusion, 18 of the 20 patients; mastoid bony coalescence, 5 of the 20 patients; enhancing soft tissue, 6 of the 20 patients; soft tissue gas, 6 of the 20 patients; temporomandibular joint/condylar erosion, 3 of the 20 patients. Three patients developed an abscess.

Conclusion: Mastoid effusion and external auditory canal erosions are commonly seen with TB-ORN. Clinically moderate or severe cases of TBORN are more likely to demonstrate enhancing soft tissue (P = 0.002), soft tissue gas (P = 0.002), and temporomandibular joint involvement (P = 0.07).