The audiometric pattern in patients with otosclerosis and outcomes of stapedectomy are variable. Whether this has anything to do with the number of sites affected by otosclerosis in the otic capsule and the disease pattern according to foci location, foci characteristics, extension to the cochlear endosteum, and presence of internal auditory canal diverticula, is the subject of this study. The authors analysed 40 ears through high-resolution CT scans (HRCT). Blinded evaluation was carried out by experienced radiologists. Preoperative audiometry was performed within three months of surgery. The audiometric parameters used were pure-tone average across all frequencies, high frequency pure-tone average and bone conduction pure-tone average. The PTA averages were higher if more sites were involved but there was no statistically significant difference. However, the bone conduction was statistically worse for more sites involved within the otic capsule. There was no statistically significant difference in the audiometric parameters between active (otospongiosis), inactive (otosclerosis) and mixed type of lesions. The audiometric values were worse for endosteal extension but not statistically significant. As for the presence or absence of internal auditory canal diverticula, the audiometric values were worse for the former but, again, not statistically significant. The authors contend that high-resolution CT scans are useful in assessing the clinical scenario of otosclerosis, particularly in relation to sensorineural loss preoperatively which would affect the outcome immediately and in the long term. This could possibly help patient choice in terms of surgery, bone-anchored hearing aid or stapedectomy. A long-term postoperative follow-up in relation to these features would be interesting.