Objective: The purpose of this study was to investigate the incidence of endolymphatic hydrops (EH) and the clinical features in patients with atypical Ménière's disease (aMD), by 3-T gadolinium-enhanced magnetic resonance imaging (MRI).

　Methods: Thirty-three patients who were diagnosed as having aMD participated in this study. Out of the 33 patients, 23 were classified as having cochlear MD (CMD) and the remaining 10 as having vestibular MD (VMD). 3-T MRI was performed 24 hours after intratympanic injection of gadolinium in 24 patients, and 4 hours after intravenous injection of gadolinium in the remaining 9 patients. We investigated the prevalence rate of EH, the relationship between detection of EH and the duration of illness, and the transition rate to classical MD in the study participants. In addition, in the CMD group, the degree of hearing fluctuation was also evaluated.

　Results and Conclusions: The incidence of EH was 78.3% (18/23) in the CMD group and 40% (4/10) in the VMD group. There was no significant difference in the prevalence of EH in relation to the duration of illness between the two groups. The degree of hearing fluctuation in the patient group with CMD was slightly greater in the patients with EH than in those without EH. It was assumed that patients with other diseases causing episodic vertigo were diagnosed could be misdiagnosed as having VMD, and that 3-T MRI with gadolinium injection could be a good diagnostic tool for confirming the presence of EH.