Measurement of stapes footplate thickness using ultra-high-resolution computed tomography: stapes axial plane correlates better with otosclerosis than lateral semicircular canal plane.

BACKGROUND, AIMS Stapes footplate thickness measurement using ultra-high-resolution CT has been described only in the lateral semicircular canal plane. The purpose of this study was to compare stapes footplate thickness between the lateral semicircular canal and stapes axial planes in patients with otosclerosis compared to controls. MATERIAL AND METHODS We performed a retrospective single-center study of patients undergoing high-resolution temporal bone CT. Two radiologists measured stapes footplate thickness in both the lateral semicircular canal and stapes axial planes. RESULTS Between February 2020 and October 2022, we collected 81 ears from 49 patients (75% of women; mean age 51.22 ± 16.6 years, 17 otosclerosis, and 64 controls). In the stapes axial plane, there was a significant anterior thickening in otosclerosis patients (Reader 1: 0.52 ± 0.12 [0.3-0.7] vs. 0.41 ± 0.08 [0.3-0.6], p = 0.001; Reader 2: 0.54 ± 0.06 [0.5-0.7] vs. 0.39 ± 0.08 [0.2-0.6], P < 0.001) compared to controls. These differences were not significant using the lateral semicircular canal plane. CONCLUSION The stapes footplate was thickened at its AC in otosclerosis patients using only the stapes axial plane. SIGNIFICANCE We propose to use the stapes axial plane instead of the lateral semicircular canal plane when analyzing the stapes.