Semilongitudinal and axial CT planes in assessing cochlear patency in cochlear implant candidates

Objective: To investigate how cochlear patency as seen on computed tomography (CT), using axial plus semilongitudinal planes, is correlated with findings at surgery in cochlear implant patients. Methods: Pre-operative CT scans of 45 patients were reviewed by three, independent observers. They classified the cochlear patency and recorded the location of any suspected decreased patency. The results were compared with the findings noted during surgery. Results: In nine patients a decreased cochlear patency was found at surgery. The sensitivity and specificity of CT assessment were, respectively, 56–33–11% and 100–86–94%. The interobserver reproducibility is reflected in a mean kappa of 0.46. The sensitivity increased when only patients suffering from post-meningitic deafness were considered. Conclusion: Our study suggests that CT scans can be useful in assessing cochlear patency, especially in patients with post-meningitic deafness. This good performance might be explained by the combined use of scans in semilongitudinal and axial planes.