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

Abstract

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.

Chinese Abstract

背景和目的：使用超高分辨率 CT 测量的镫骨足板厚度仅在侧半规管平面所描述。 本研究的目的是比较耳硬化症患者的側半规管与镫骨轴面之间的足板厚度, 并和对照组相比较。

材料和方法：我们对接受高分辨率颞骨CT的患者进行了一项回顾性单中心研究。 两位放射科医生测量了侧半规管和镫骨轴面两个部位的镫骨足板厚度。

结果：2020 年 2 月至 2022 年 10 月期间, 我们收集了 49 名患者的 81 只耳朵（女性占 75%, 平均年龄 51.22±16.6 岁, 17 只耳患耳硬化症, 64 只对照耳）。 在镫骨轴面, 耳硬化症患者的前壁显著增厚（读数 1：0.52±0.12 [0.3-0.7] 相比于对照耳 0.41±0.08[0.3-0.6], p=0.001； 读数 2： 0.54±0.06 [0.5-0.7] 相比于对照耳0.39±0.08 [0.2-0.6], P<0.001）。使用外侧半规管平面时这些差异并不显著。

结论：仅使用镫骨轴向平面时, 耳硬化症患者镫骨足板在 AC 处增厚。

意义：我们建议使用镫骨轴向平面代替外半规管平面来分析镫骨。

Keywords:

• Otosclerosis
• CT
• ultra-high resolution
• stapes
• temporal bone
• semi-circular canals

Disclosure statement

Two authors of this work are on a non-remunerated research contract with Canon Medical Systems.