High-resolution CT and cochlear densitometry in otosclerosis

Abstract Problem: Otosclerosis is a primary local disease of the otic capsule that affects the enchondral layer of the human temporal bone. It develops in the oval window area in most of the cases followed by the round window niche and the inner ear. The aim of this study is to evaluate the sensitivity of high-resolution Computer Tomography (CT) and the cochlear densitometry in the diagnosis of otosclerosis. Methods: This is a prospective study conducted at the Hospital Italiano de Buenos Aires (Argentina) from August 2000 to November 2003. It includes all patients with suspected diagnosis of otosclerosis later confirmed at surgery having a CT scan and a cochlear densitometry performed previously to surgery. Results: Twenty-eight ears (24 patients, 15 females; mean age, 37 years) were studied. Thirteen ears had a mixed-type hearing loss, among them 11 had a pathologic CT and 9 had an abnormal densitometry profile. Fifteen ears had a conductive hearing loss; 8 of them presented CT and densitometric alterations. Conclusion: The diagnosis of otosclerosis is based on the clinical symptoms, individual family history, a complete audiological evaluation and confirmed during surgery. The CT cochlear densitometry sensitivity was of 60.7%. The high-resolution CT had a sensitivity of 68% in the otosclerosis diagnosis, which went up to 84% when the cochlea was affected. Significance: The high-resolution CT constitutes an objective approach to otosclerosis diagnosis, especially in those patients with cochlear affectation. Support: No grants or other support have been received for this research.