Diffusion tensor imaging of the auditory pathway in sensorineural hearing loss: changes in radial diffusivity and diffusion anisotropy

Purpose: To prospectively compare diffusion tensor imaging (DTI) measures of axial diffusivity (lambda||), radial diffusivity (lambda perpendicular to), mean diffusivity (MD), and fractional anisotropy (FA) along the auditory pathway of patients with sensorineural hearing loss (SNHL) and normal controls. Materials and Methods: In 37 individuals with SNHL and 10 healthy controls, two regions of interest (ROIs) positioned along the auditory pathway-the lateral lemniscus (LL) and the inferior colliculus (IC)-were investigated bilaterally using diffusion tensor imaging at 3 T. SNHL patients were divided into three groups: patients with bilateral hearing loss, patients with unilateral hearing loss, and patients with partial hearing loss. DTI measures (lambda||, lambda perpendicular to, MD, FA) of both ROIs were determined in all subjects. Results: The FA value was reduced and the lambda perpendicular to was increased both at the lateral lemniscus and the inferior colliculus of patients with SNHL compared with controls. Similar changes were seen between the ipsilateral and contralateral LL and IC: for patients of unilateral profound heating loss. No changes were observed in any other parameters. Conclusion: In SNHL patients DTI showed a high radial diffusivity that consequently led to a decreased fractional anisotropy in the LL and the IC.