Which is the optimally defined vestibular cross-section to diagnose unilateral Meniere's disease with delayed post-gadolinium 3D fluid-attenuated inversion recovery MRI?

OBJECTIVES: Delayed post-gadolinium 3D fluid-attenuated inversion recovery (FLAIR) MRI is used to support a diagnosis of Ménière's disease (MD) with the ratio of the endolymphatic space (ES) to the sum of the endolymphatic and perilymphatic spaces (SEPS) on a cross-section through the vestibule being a key diagnostic criterion. It was hypothesised that the exact definition of the vestibular cross-section would influence the ES: SEPS ratio, its ability to diagnose MD, and its reproducibility. METHODS: Following institutional approval, 22 patients (five male, 17 female; mean age 52.1) with unilateral MD and delayed post-gadolinium 3D FLAIR MRI were retrospectively analysed. Two observers measured the ES and SEPS on predefined axial (superior and inferior) and sagittal vestibular cross-sections. Receiver operating characteristic (ROC) curves, Bland-Altman plots and intraclass correlation (ICC) were analysed for the ES:SEPS ratios. RESULTS: The area under the curve (AUC) was decreased for the ES:SEPS ratios on the superior axial section through the vestibule (AUC 0.737) compared to the inferior axial (AUC 0.874) and sagittal sections (AUC 0.878). The resulting optimal thresholds (sensitivities/specificities) were 0.21 (0.66/0.75), 0.16 (0.77/0.9) and 0.285 (0.75/0.96). The reproducibility was excellent for all measures with ICCs of 0.97, 0.98 and 0.99. CONCLUSION: Inferior axial or sagittal vestibular cross-sections are more accurate for the diagnosis of MD ears and have excellent reproducibility. ADVANCES IN KNOWLEDGE: The choice of vestibular cross-section influences both the ability to distinguish MD from asymptomatic contralateral ears, and the optimum threshold ES:SEPS value.