ABSTRACT
The availability of HRCT with it is detailed anatomical visualization of fine structure of middle and inner ears makes it the best modality in the diagnosis of otosclerosis. Twenty patients were examined and operated for otosclerosis, the females were more involved and 75% of cases had bilateral involvements, with positive family history supporting its inherted back ground. to evaluate the accuracy of HRCT in preoperative evaluation of otosclerosis. Result and CT scan visualize otospongiosis as illdefined hypodensities at oval window, lateral labyrinthine wall and as around the cochlear turns. The disease is in pure sclerotic phase, underestimation is suspected. The volume average artifact decrease the ability in detecting thickened footplate or stapes crus. Postoperative evaluation by CT scan explains the causes of surgical failures of disease recurrence