[The radiological pattern of cochlear otosclerosis. A CT study of 14 patients].

In this review of cochlear otosclerosis 14 cases were studied by CT scan aiming to establish a densitometric pattern of the capsular foci and relating it to the hearing and vestibule dysfunctions. Severe demineralization with characteristics of probable activity (increased lucency of 30-40%) was demonstrated in the capsular foci. These were mainly cochlear with endosteal involvement (93%): large (64%) or discrete (29%). Cochlear otosclerosis was widespread in 64% of the patients, with coexisting foci in the semicircular canals (38%), vestibule aqueduct (43%) and internal auditory canal (43%). The antefenestral component with stapes involvement was 85%, mostly of the anterior polar and crural varieties (64%) and signs of activity. In 2 patients there was a conductive hearing loss in the tonal audiometry, pure or combined; in 2 others there was only a pure perceptive hypoacusis of type IV. A direct relationship was noted (64% of cases) between the most serious hypoacusis (type III and IV) and the endosteal extension of the cochlear foci. Vertigo occurred in 36% of the patients and was attributed to the posterior labyrinth foci.