The Role of CT Scan in the Diagnosis of Otosclerosis

Objective: Otosclerosis has long been a clinical, audiological and tympanometric diagnosis. The definitive role and value of imaging is yet unclear in the clinical practice. In this work we aimed to study the temporal bone density using CT scan in patients clinically diagnosed as otosclerosis, not only to ascertain the value of CT scan, but also to study the correlation between the bone density and the audiological status. Patients and Methods: Two groups of patient's temporal bones were investigated in this study. Study group: included 30 temporal bones (From 13 patients with clinically and audiologically diagnosed bilateral otosclerosis and 4 patients diagnosed with unilateral disease). Control group: included 22 temporal bones (from the normal temporal bones of 18 patients suffering from unilateral cholesteatoma and the normal temporal bones of 4 patients suffering from unilateral otosclerosis). All the temporal bones were investigated by bone density measurement at the fissula ante fenestrum (FAF). The density measurement together with its extent were correlated with the hearing status of the patients. Results: A positive correlation was elicited between the degree/extent of hypodensity at the FAF and the audiological air bone gap as well as the bone conduction threshold. Conclusion: CT scan using bone density measurement is a useful sensor to diagnose otosclerosis radiologically. An observation that should be taken in consideration for the future diagnosis of cochlear otosclerosis in patients with sensorineural hearing impairment of undetermined etiology, utilizing the value of bone density measurement rather than the morphoradiological findings which are often invisible.