Contrast Agent Uptake in Endolymphatic Sac and Duct: Inverse Relation to Endolymphatic Hydrops

ABSTRACT Objectives Ménière's disease (MD) and vestibular migraine (VM) can be associated with endolymphatic hydrops (ELH). The differential role of the endolymphatic sac and duct (ES/ED) system for the development of ELH is poorly understood. Methods On 251 delayed, contrast‐enhanced inner ear MRI (iMRI) datasets from neurotological patients and healthy control participants, we evaluated (1) the visibility of the ES/ED system using a novel semi‐quantitative scale, and (2) the dimensions of ELH, calculated using volumetric local thresholding (VOLT). Afterwards, statistical analysis of ES/ED radiologic visibility in relation to the grade of ELH, the degree of clinical symptoms, and audiometric findings was performed. Results Patients were divided into an MD cohort ( n = 68, 34 females, mean age 54.5 ± 14.8 years) and a VM cohort ( n = 67, 42 females, 45.9 ± 15.5 years). The remaining datasets did not fulfill diagnostic criteria for definite diagnoses ( n = 64, 27 females, mean age 51.3 ± 16.6) or were from healthy controls (HC; n = 52, 27 females, 49.0 ± 18.1 years). MD patients showed the lowest ES/ED‐visibility scores on the affected side (ANOVA F(172,2): 20.60, p < 0.001), while the ES/ED‐visibility on the non‐affected side in MD patients was still significantly lower than in VM and HC (ANOVA F(172,2): 6.80, p 1.44 × 10 −3 ). The ES/ED‐visibility score and ELH volume (determined by VOLT, in mm 3 ) correlated inversely (Spearman's rho: −0.32, Fisher's z −0.34, p < 0.001). Conclusion ES/ED radiologic visibility in iMRI is inversely associated with ELH volumes. Patients with MD show substantially decreased ES/ED visibility on the affected ear and (less pronounced) on the unaffected ear, while VM and HC exhibit normal ES/ED visibility. Level of Evidence: 3.