Interpreting pre-operative mastoid computed tomography images: comparison between operating surgeon, radiologist and operative findings

This study aimed to compare the interpretations of temporal bone computed tomography scans by an otologist and a radiologist with a special interest in temporal bone imaging. It also aimed to determine the usefulness of this imaging modality. A head and neck radiologist and an otologist separately reported pre-operative computed tomography images using a structured proforma. The reports were then compared with operative findings to determine their accuracy and differences in interpretations. Forty-eight patients who underwent pre-operative computed tomography scans in a 30-month period were identified. Six patients were excluded because complete operative findings had not been recorded. Positive and negative predictive values and accuracy of the anatomical and pathological findings were calculated for 42 patients by both reporters. The accuracy was found to be less than 80 per cent, except for identification of the tegmen and lateral semicircular canal erosion. Overall, there was no significant difference in interpretations of computed tomography scans between reporters. There was a slight difference in interpretation for tympanic membrane retraction, facial canal erosion and lateral semicircular canal fistula and/or erosion. Pre-operative computed tomography scanning of the temporal bone is useful for predicting anatomy for surgical planning in patients with chronic otitis media, but its reliability remains questionable.