CT Findings of Otosclerosis

Objective To evaluate the high-resolution CT (HRCT) findings of otosclerosis and its value in clinical practice.Materials and Methods 24 cases with otosclerosis were analyzed retrospectively which were pathologically proved, axial and coronal HRCT scanning was performed with 1mm slice thickness, 1mm space, windows level 700HU and windows with 4 000HU.Results Hypodensity was shown in the anterior oval window region on 13 left ears and 12 right ears, also in the peripheral cochlear region on 7 left ears and 7 right ears. Thickening of stapes footplate was in 6 cases, including 3 on left ear and 3 on right ear. Relapsing of stapes footplate was in 5 cases, including 2 on left ear and 3 on right ear. Broadening of oval window was in 4 cases, 2 on left and 2 on right, narrowing of oval window was in 6 cases, 2 on left and 4 on right. Conclusion Otosclerosis occurs in young female predominantly. The lesion of otosclerosis may involve all parts of otic capsule, most commonly in the anterior oval window region approximate to the promontory. In active phase, the lesion may be manifested hypodensity, oval window broadening, footplate relapsing, while in mature phase oval window was narrowing so much as obstructing. The peripheral region of cochlear may be exhibited “spot” or “arc-line” lesion, typically “double-ring” sign. CT can clearly display the extension and degree of lesion, which is helpful for diagnosis and follow-up of the disease.