“…Furthermore, FCD has been considered to be a negative prognostic factor for surgical outcome in COM surgery [16]. In this regard, highresolution computed tomography (HRCT) of the temporal bone provides valuable data since it can determine the cholesteatoma tissue and its extent, and assess the ossicles, facial canal, tegmen, PWEAC, bony plate over the sigmoid sinus and jugular vein, carotid canal, and inner ear structures [17][18][19]. Low-lying dura or anteriorly located sigmoid sinuses, which are considered important in mastoid surgery, can also be visualized preoperatively via HRCT scanning.…”