Background: The aim of this study was to identify the incidence of endolymphatic hydrops using 3-dimensional fluid-attenuated inversion recovery (3D-FLAIR) magnetic resonance imaging (MRI) in the contralateral ear in patients with unilateral Ménière’s disease (MD).
Material and Methods: This was a prospective study. 3D-FLAIR MRI was performed with a 3 Tesla (3 T) unit 24 h after the intratympanic administration of gadolinium (Gd) in 30 unilateral MD patients with an asymptomatic contralateral ear. The incidence of contralateral involvement in unilateral MD patients and the potential correlations between the affected and contralateral ears were analyzed.
Results: Endolymphatic hydrops was observed in 7 of the 30 (23.3%) asymptomatic ears. The mean PTA of the asymptomatic ears in the contralateral hydrops patients (33.0±6.1 dB) was significantly higher compared with the non-hydrops patients (17.8±5.7 dB). The patients with observed contralateral hydrops exhibited a significantly longer duration of the disease compared with the non-hydrops patients (6.7±6.3 vs. 2.9±3.1 years, respectively). Furthermore, the patients with contralateral hydrops had a worse hearing level in the affected ears compared with the non-hydrops patients (70.3±7.4 vs. 52.5±3.8 dB, respectively).
Conclusions: Endolymphatic hydrops is closely related to hearing loss but does not necessarily result in Ménière’s symptoms. Patients with a long history of MD and severe hearing loss in the affected ear are more likely to exhibit endolymphatic hydrops in the asymptomatic contralateral ear. Adequate attention should focus on unilateral MD patients with contralateral ear hydrops because of the potential to develop bilateral MD.

Keywords: Ear - pathology, Aged, Adult, Endolymphatic Hydrops - diagnosis, Female, Gadolinium - administration & dosage, Humans, Imaging, Three-Dimensional, Injections, Magnetic Resonance Imaging, Male, Meniere Disease - diagnosis, Middle Aged, Tympanic Membrane - pathology