The predictive value of semilongitudinal and axial computerized tomography planes in assessing cochlear patency in cochlear implant candidates

Introduction. The objective was to establish the predictive value of semilongitudinal and axial computerized tomography (CT) planes in assessing cochlear patency in cochlear implant candidates. Methods. In a retrospective study, preoperative CT scans of 45 patients who received a cochlear implant were independently reviewed by a junior and senior observer. The predicted degree of cochlear patency was compared with the peroperative findings. Results. A decreased cochlear patency was found at surgery in nine patients (20%). The sensitivity of CT was 33% for the junior observer and 11% for the senior observer, whereas specificity was 86% and 89% respectively. Inter-observer reliability was reflected in a kappa of 0.38. In 14 patients deafened as a result of meningitis (31%), sensitivity for the junior observer amounted to 60% with a specificity of 89%. Statistical analysis revealed that this improvement did not solely depend on a higher prevalence of decreased cochlear patency. Conclusion. The sensitivity of CT scans in the semilongitudinal and axial plane in assessing cochlear patency, in our patient group, is small. In patients deafened as a result of meningitis, sensitivity was found to be increased.