In vivo Assessment of an Endolymphatic Hydrops Gradient Along the Cochlea in Patients With Meniere's Disease by Magnetic Resonance Imaging-A Pilot Study

Objective: To assess three strategies for evaluation and description of potential endolymphatic hydrops (EH) gradients along the cochlea in patients with Meniere's disease. Study Design: Prospective observational study. Methods: Ten patients with definite Meniere's disease revealed by magnetic resonance imaging were included in this prospectively conducted pilot study. The presence of cochlear endolymphatic hydrops as well as a potential hydrops gradient along the cochlea were subjectively evaluated by two readers. Furthermore, both readers performed planimetric measurements of the relative extent of endolymphatic hydrops in the cochlear turns for calculation of an apico-basal-index (ABI) and an average gradient slope of the endolymphatic hydrops. These models were correlated with the available pure tone audiometry (PTA). Results: Qualitatively, 13 of 16 inner ears presented an apical EH distribution. The median ABI was 1.69 for patients with low-tone hearing loss and 1.17 for patients with a flat PTA curve (p = 0.03). The median EH slope was 7.44 and correlated with the steepness of the PTA (r = 0.583; p = 0.018). The subjective analysis and the slope model were best fit for prediction of a low-tone hearing loss type with sensitivities of 100% (specificity, 42.86%) and 88.9% (specificity, 71.4%), respectively. The inter-reader agreement in all three approaches was considered substantial to perfect. Conclusion: The presented qualitative approach and the slope model represent reliable methods for the description of a potential EH gradient along the cochlea. Furthermore, the average EH steepness along the cochlea correlates with the type of hearing loss.