Inclusion Criteria:  Adult patients (18 years and older) Requiring radiological assessment for conductive hearing loss with intact tympanic membrane, confirmed by otoscopy and audiogram Signed informed consent Affiliated or beneficiary of health insurance  Exclusion Criteria:  Absence of otosclerosis on the MDCT History of middle ear surgery Pregnancy, breast feeding women and women who are of childbearing age and not practicing adequate birth control Patient under legal protection