Evaluation of Cochlear Nerve Diameter with MRI in Patients with Idiopathic Unilateral Sensorineural Hearing Loss

Objective The aim of this study was to evaluate the cochlear nerve diameter in patients with unilateral sensorineural hearing loss and to compare the diameter of the normal sidewith the hearing loss side.Materialsand MethodsA total of 36 patients with idiopathic unilateral sensorineural hearing loss were included in the study. Magnetic resonance imaging (MRI) and pure sound audiogram wereperformed on all the patients. Both cochlear nerve diameters were measured on axial thin-section constructive interference in steady state (CISS) sequences.Results The patients were comprised of 16 males and 20 females with a mean age of 52.3±13.7 years. Hearing loss was in the right ear in 11 patients, and in the left ear in 25. Theaverage cochlear nerve diameter on the side with hearing loss was 0.13 cm while it was 0.19 cm on the normal side. There was a statistically significant difference betweenthe two sides (p < 0.001).Conclusion In patients with unilateral sensorineural hearing loss, MRI allows the assessment of the cochlear nerve with anatomic detail, and enables the exclusion of possible organicpathologies. Demonstration of decreased cochlear nerve diameter in idiopathic sensorineural hearing loss will contribute to elucidating the etiology of this disease in thefuture.