Comparison of manual and computer-assisted measurement of cochlear nerve obtained from magnetic resonance imaging

Abstract

Objectives: Cochlear implantation of sensorineural hearing loss requires accurate measurement of cochlear nerve (CN). The precise measurement of very small structures can be improved by automated segmentation and measurement. The variability and reproducibility of the computer-assisted measurement were compared with manual measurements. Materials and Methods: The 3D-constructive interference in steady state magnetic resonance imaging (MRI) images of twenty patients who were referred for MRI in the assessment of giddiness/vertigo or fitness for cochlear implant during the period from June 2013 to June 2014 were analyzed. The CN sizes were measured manually by two independent radiologists. The automatic measurements were then performed on the same images, and its correlation and agreement were calculated between automated and manual measurements. Results: The intra-observer correlation coefficients were significantly larger for cross-sectional area (CSA) of CN using automated measurements when compared to manual measurement (intra-observer r: 0.94021 vs. 0.91437). Similarly, the inter-observer correlation for CSA of CN is also higher in automated measurements (inter measurement r: 0.94786 vs. 0.92013). Conclusions: Using computer-assisted CN dimension measurement, the intra- and inter-observer correlation can be improved when compared to manual measurements. The automated measurement can assist the radiologist in eliminating the need for tedious manual tracing and thus, the time and effort for manual segmentation are also significantly reduced.