THE ROLE OF HRCT IN EVALUATION OF AQUAIRED MIDDLE EAR CHOLESTEATOMA OTITIS PRIOR SURGERY

Abstract

Otoscopic examination is the best method for diagnosis of cholesteatoma which treated by explorative surgery. The need for pre-operative imaging studies is controversial. This study assesses the accuracy and usefulness of a pre-operative high-resolution CT scan in depicting the status of the middle ear structures in the presence of cholesteatoma.
Patients and Methods: the surgical findings of 88 patients with acquired cholesteatoma were compared with the pre-operative CT findings in this prospective study. The following were analyzed: diagnostic features of cholesteatoma on CT, status of the middle ear structures (ossicles, facial nerve canal, bony labyrinth, tegmen tympani and scutum) and extension of the disease to the sinus tymapni and facial recess.
Results: eighty-three (94.3%) cases had the two radiological features characteristic for cholesteatoma (a) a location typical for cholesteatoma in the epitympanum and mastoid antrum (b) bony erosion.
The radio-surgical agreement was excellent for the malleus (Kappa statistics, K= 0.96), stapes (0.91), bony labyrinth (0.94), tegmen tympani (0.82) and scutum (1), good for the incus (0.75), but poor for the facial nerve canal (0.39). The scan accurately predicted the extension of the disease to the sinus tympani and facial recess.
Conclusion: High-resolution CT scan is an important investigative tool prior to cholesteatoma surgery.There is good to excellent radio-surgical correlation in cholesteatoma for most middle ear structures except for the integrity of the facial canal. The scan alerts the surgeon to asymptomatic complication of the disease.