Twelve patients with surgically proven otosclerosis and sensorineural hearing loss were studied with high-resolution computed tomography (CT). The purpose was to Identify abnormal bony changes that could be diagnostic of cochlear otosclerosis. Of the 24 temporal bones thus studied, 10 showed positive findings. The findings in our study—as well as those of others—show a pericochlear zone of radiolucency. The precise origin of this is undetermined.