Thirty-five consecutive patients with the clinical diagnosis of fenestral otosclerosis were evaluated with high-resolution computed tomography (CT). Twenty-six were diagnosed as having this disorder by CT evidence of abnormal bony excrescences at or adjacent to the oval window. The diagnosis was made upon examination of 1.5-mm-thick targeted sections obtained at 0.5-mm intervals in the axial projection. Coronal sections were also included. Sections were also evaluated for evidence of plaque formation elsewhere in the lateral wall of the labyrinth and for surgical obstacles such as an abnormally wide cochlear aqueduct, a high jugular vein, and a dehiscent facial nerve. It is concluded that fenestral otosclerosis may be accurately diagnosed with proper CT techniques.

Ninety patients who had suspected or confirmed fenestral or cochlear otosclerosis underwent CT examination. Foci of demineralization in the otic capsule were discovered in 20 ears (12 patients). Audiometric studies of the 12 patients revealed sensorineural hearing loss (SNHL) with distinct correlation of CT findings with progressivity and with involvement of the frequency level subtended by the specific area of the cochlea involved. Foci of abnormal increased density, presumably representing the healed phase of this disorder, were found less frequently than expected. There was a predilection for the basilar turn. All patients had static SNHL in the higher frequencies. The healed phase of this disorder is probably not consistently diagnosable with CT.

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Of more than 200 patients who underwent high-resolution computed tomography (CT) of the middle ear, the vast majority had tubotympanic disease in one of its forms: middle ear effusion, tympanosclerosis, granulation tissue, tympanic membrane retractions, or acquired cholesteatoma. The CT appearance of each of these conditions is discussed and illustrated. Emphasis is placed on the differential diagnosis of tubotympanic disease by determining dependent from nondependent soft-tissue opacity using two CT projections.

Postinflammatory ossicular fixation is a common problem encountered by the otologic surgeon upon exploration because of conductive hearing loss in patients with chronic otitis media. These nonotosclerotic noncongenital lesions take three pathologic forms: fibrous tissue fixation (chronic adhesive otitis media), hyalinization of collagen (tympanosclerosis), and new bone formation (fibro-osseous sclerosis). Fibrous tissue fixation appears on CT as nonbony, noncalcific soft-tissue debris encasing some or all of the ossicular chain. Tympanosclerosis appears as unifocal or multifocal punctate or weblike calcifications in the middle ear cavity or on the tympanic membrane. This debris may be in direct apposition to the ossicular chain or may replace the suspensory ligaments in symptomatic patients. New bone formation has been identified only in the attic and is the least common manifestation. Thick bony webs or generalized bony encasement may be present at CT. More than 300 patients with the clinical diagnosis of chronic otitis media have been examined. This study encompasses 23 proved cases.