Chakenahalli P. Nanjaraj1, Pradeep Hagalahalli Nagarajegowda2, Vijay Prakash Kannan3, Pradeep Kumar Chandanur Nagarajaiah4
PURPOSE To correlate the sensitivity and specificity of High Resolution Computed Tomography (HRCT) findings of temporal bone in chronic otitis media with surgical findings. MATERIALS & METHODS HRCT of temporal bone of fifty patients with chronic otitis media were evaluated prospectively between July 2012 and December 2013. The various pathological findings, complications and important anatomical variations were evaluated. These findings were compared with intraoperative findings. Statistical methods were carried out using SPSS for Windows (Version 16.0) and Minitab (Version 11.0) for windows. The sensitivity, specificity, false positive and false negative rates were calculated. The level of significance was considered significant for P-values <0.05. RESULTS HRCT is reliable for all the parameters like scutum erosion, ossicular erosion, mastoid pneumatisation, low lying dura, anterior lying sigmoid, Korner’s septum, cholesteatoma extension in middle ear and mastoid, and presence of complications like mastoiditis, mastoid abscess, mastoid cortex dehiscence, sigmoid sinus plate erosion, facial canal dehiscence, tegmen mastoideum erosion, labyrinthine fistula and intracranial complications with a P value <0.05 but not reliable for tegmen tympani erosion and posterior fossa dural plate erosion. Among the findings related to adjacent neurovascular structures, facial canal dehiscence was commonest followed by anterior lying sigmoid sinus and low lying dura. In ossicular erosion, incus was most commonly involved followed by stapes and malleus. Most of the mastoid in this study was sclerotic followed by pneumatised and diploic. The epitympanum and mastoid antrum were the most commonly involved areas in cholesteatoma followed by aditus, mastoid air cells, posterior tympanum, mesotympanum, hypotympanum, protympanum and perilabyrinthine air cells in decreasing order of frequency. CONCLUSIONS HRCT temporal bone is a reliable investigation in preoperative evaluation of chronic otitis media and its complications, but unreliable for tegmen tympani and posterior fossa dural plate erosion.
