中耳真珠腫のX線断層診断

概要

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Tomographic study coupled with information obtained from otoscopic observation of the ear drum, middle ear and audiometry provide otologists with a complete picture of cholesteatomatous involvement of the temporal bone. Tomographic studies were performed in our clinic preoperatively using a Hitachi Polytome. The ear was sectioned at consecutive levels 2.5mm apart with 4 cuts for lateral projection and 5 for frontal. Diagnosis of cholesteatoma was made when there were tomographic findings of widening over 3mm of spur interval (distance between the lateral aspect of the head of malleus and the lateral attic wall), destruction of the anterior tympanic spine and an excessively blurred attic.In the retrospective review of tomograms of the surgically treated patients, we found changes compatible with cholesteatoma in 89% of 46 patients with surgically confirmed cholesteatoma. Tomographically we were able to determine the size and extent of cholesteatoma as well as the involvement of the ossicles, dural plate, facial canal, lateral sinus and lateral semicircular canal. Forty-six cases of cholesteatoma were classified according to the site and the extent of cholesteatoma into three types: the attic type (13 ears), the tympanic type (15) and the advanced type (18).Thus the usefullness and accuracy of preoperative tomographic examinations in cholesteatoma cases have been well demonstrated.
耳鼻咽喉科臨床学会の論文