Morphometric analysis of facial and cochlear nerves in normal-hearing ears using 3D-CISS

Abstract

Purpose: The aim of the current study was to establish a normative data set for the morphometric parameters of the facial nevre (FN) and cochlear nevre (CN) according to age and sex in the adult population, using 3-dimensional constructive interference in steady state (3D-CISS) sequence on magnetic resonance imaging. Methods: We retrospectively analyzed 157 ears of 102 adults with no hearing impairment, facial palsy or Ménière's disease. The vertical (VD) and horizontal (HD) diameters as well as cross-sectional areas (CSAs) of the FNs and CNs were measured on the parasagittal oblique image created using the axial 3D-CISS sections passing through the internal acoustic canal. We related the measurement results with side, sex and age. Results: The mean VD, HD and CSA of the FNs were 1.09 ± 0.18 mm, 0.84 ± 0.17 mm, and 0.75 ± 0.27 mm2, respectively, whereas those of the CNs were 1.34 ± 0.17 mm, 1 ± 0.15 mm and 1.06 ± 0.3 mm2, respectively. There was no statistically significant difference between the morphometric parameters of both the nerves according to side or sex (P > 0.05). However, except for the CSA of the FNs among males, we found a statistically significant decrease in all the morphometric parameters of both the nerves with ageing (P < 0.05). Conclusion: The normative morphometric data obtained in this study can be beneficial in clinical applications for sensorineural hearing loss, facial palsy and Ménière's disease. Keywords: Cochlear nerve, Facial nerve, 3 dimensional constructive interference in steady state (3D-CISS)