Quantitative study of vestibular endolymphatic hydrops in Meniere's disease based on Three-Dimensional real Inversion Recovery (3D-real IR) sequence.

Objective: To establish objective criteria for grading vestibular endolymphatic hydrops (EH) in Meniere's disease (MD) using 3D-real IR MRI, and investigate its clinical correlations.

Methods: Retrospective analysis of 155 MD patients (189 ears) included clinical data, audiovestibular assessments, and gadolinium-enhanced MRI. Vestibule volume (VV) and the volume of vestibular endolymph (EndV) were outlined on 3D-real IR sequence images, and the volume of vestibular endolymph was calculated by the vestibular endolymphatic ratio (ELR) to evaluate the degree of EH, analyze the correlation between the degree of EH and specific clinical features, hearing and vestibular function, and determine the optimal ELR value to differentiate each degree of effusion by using receiver operating characteristic (ROC) curve analysis.

Results: EH severity significantly correlated with disease stage (P < 0.001), pure-tone average (P < 0.001), age (P < 0.01), and caloric weakness (P < 0.01), but not with gender, disease duration, vertigo frequency, tinnitus, aural fullness, or electrocochleography. Affected ears demonstrated significantly different EndV (0.013 ± 0.003 vs 0.005 ± 0.001 cm) and ELR (33.6 ± 12.1 % vs 6.4 ± 2.7 %) compared to controls (P < 0.01), while maintaining comparable VV (0.08 ± 0.016 cm). ROC analysis established ELR thresholds of 16 % (AUC = 0.905), 34 % (AUC = 0.871), and 47 % (AUC = 0.899) differentiating no hydrops from grade I, grade I from II, and grade II from III, respectively.

Conclusion: 3D-real IR MRI enables quantitative EH assessment, with ELR thresholds providing objective grading criteria. EH severity reflects pathophysiological progression through its associations with auditory/vestibular dysfunction and disease stage, while demonstrating stability of total vestibular volume. This methodology addresses limitations of subjective grading systems, offering standardized metrics for clinical research and therapeutic monitoring.