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

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.

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.

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 mm³) correlated inversely (Spearman's rho: -0.32, Fisher's z -0.34, p < 0.001).

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.