Endolymphatic hydrops impairs inner ear uptake and distribution of intratympanically injected gadolinium mixed with dexamethasone in patients with Meniere's disease.

Objective: To investigate how endolymphatic hydrops (EH) affects the entry of intratympanic gadolinium in the inner ear of patients with Meniere's disease (MD).

Methods: This study included 166 MD patients. MRI was performed 24 h after intratympanic injection of dexamethasone and 20-fold diluted Gd-DTPA. The region of interest with the strongest enhancement in the cochlea and vestibule was selected to calculate the signal intensity ratio (SIR), representing transport speed. The enhancement area in the vestibular perilymph, indicating the distribution volume of Gd-DTPA, was measured.

Results: EH was detected in 77.7% of patients, specifically in 60 out of 63 definite MD cases and 51 out of 103 probable MD cases. Vestibular EH with various grades was present in 76.1% of patients, whereas 17.5% exhibited impaired barriers of endolymph. Cochlear EH with various grades was observed in 68.7% of patients, and 34.9% located at the apex; 12.7% had impaired barriers of endolymph. The severity of cochlear symptoms and the stage of MD significantly correlated with the presence of EH. The vestibular SIR inversely correlated with vestibular EH. The enhancement area of the vestibular perilymph inversely correlated with EH and the stage of MD.

Conclusions: Gadolinium transport from the middle ear into the inner ear and the distribution volume in the inner ear inversely correlated with EH, which is compromised in more advanced stages MD patients.