AbstractObjective:To verify the hypothesis that intravenous frusemide reduces endolymphatic hydrops, as evaluated by three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging following intratympanic gadolinium administration.Methods:The study comprised 12 patients (7 females and 5 males, aged 19–74 years) with Ménière's disease. Disease duration ranged from 0.5 to 8 years, with a frequency of 0.5 to 6 vertigo spells per month, as calculated in the last 6 months. Three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging was performed 24 hours after intratympanic injection of gadobutrol diluted eight-fold. Frusemide 20 mg was given intravenously immediately after imaging. Magnetic resonance imaging was repeated after 1 hour, using the same parameters and sequence.Results:All patients showed enhancement defects, indicating endolymphatic hydrops of variable degrees. No modifications occurred at the second magnetic resonance imaging performed 1 hour after frusemide administration.Conclusion:There was no evidence of endolymphatic hydrops modification 1 hour after intravenously administered frusemide. Therefore, loop diuretics in Ménière's disease, which are today used on an empirical basis, must be reconsidered. Implications of these outcomes are discussed and related to the role of endolymphatic hydrops in the development of Ménière's disease.