Reproducibility of Volumetric Assessment of the Inner Ear Using Three Dimensional Reconstruction of the High Resolution MR Sequence

Purpose: to assess the reproducibility of the volumetric assessment of the inner ear using three dimensional (3D) reconstruction of the high resolution MR-Imaging (HR-MRI) sequences. Materials and Methods: The study was retrospectively performed on 50 patients referred for MRI due to different disorders of the inner ear. HR-MRI was performed using a T2-weighted SPACE sequence. 3D-reconstructions were performed using Advantage Workstation. The volumes of both inner ears together, each side alone, cochlea & vestibular system were assessed. Volume measurements were performed twice with 1 year between both measurements. The agreement between both results was tested using intra-class correlation (ICC) test. Results: For the first assessment the mean volume of both sides together was 1.01 cm3 +/-0.13, of each side alone 0.5 cm3 +/-0.07, of the cochlea 0.17 cm3 +/-0.024 & of the vestibular system 0.33 cm3 +/-0.06. For the second assessment the mean volume of both sides together was 0.99 cm3 +/- 0.11, of each side alone 0.5 cm3 +/-0.06, of the cochlea 0.17 cm3 +/-0.025 & of the vestibular system 0.33 cm3 +/-0.05. A statistically significant (p<0.0001) excellent agreement for volumetric assessment of both sides together (ICC-Coefficient=0.82) and of the cochlea (ICC-Coefficient=0.88) and substantial agreement for each side alone (ICC-Coefficient=0.79) and of the vestibular system (ICC-Coefficient= 0.7) were noted. Conclusion: Volumetric assessment of the inner ear using 3D reconstruction of HR-MRI is a reproducible method with statistically significant excellent agreement for volumetric assessment of both sides together and cochlea and substantial agreement for each side alone and vestibular system.