Diagnostic imaging in chronic otitis media: does CT and MRI fusion aid therapeutic decision making? - a pilot study

Introduction: Despite the recent advances in otosurgery diagnosis of cholesteatoma and qualification for surgery remains an issue in contemporary laryngology. In cases of cholesteatoma recidivism, it is of utmost importance to properly locate the pathology in the middle ear to plan surgical approach. Magnetic Resonance imaging in diffusion weighted non-echoplanar sequences (non-EPI DWI) enables cholesteatoma detection as small as 2 mm and could potentially prevent unnecessary second-look surgery. Computed Tomography of the temporal bone allows precise visualization of bony structures and topographical landmarks of the middle ear. A fusion of both imaging modalities combines the advantages of these techniques. Material and methods: Five patients treated in the Department of Otolaryngology, Medical University of Lodz for probable cholesteatoma recidivism were included in this study. A high-resolution CT scan of the temporal bone and an MRI scan including non-EPI sequences was obtained in all patients. A fusion of CT and MRI studies was conducted using OsirixMD software. Fist, CT studies were fused with MRI BFFE sequences, then non-EPI sequences were added. Finally, if the patient qualified for surgical treatment histopathological diagnosis was compared with MRI results. Results: CT scans were analyzed to establish the extent of previous surgical interventions and anatomical landmarks preservation. In all cases MRI results were suspicious of cholesteatoma recidivism. Four cases were confirmed in postoperative histopathological evaluation, there was one false positive case when intraoperatively scar tissue was identified, which was later confirmed as connective tissue upon histopathological evaluation. Conclusions: CT and MRI fusion provides a helpful diagnostic tool in preparation for surgery in patients with suspected cholesteatoma recidivism. Key words: magnetic resonance, computed tomography, cholesteatoma, canal wall-up surgery