Magnetic resonance imaging assessment of endolymphatic hydrops in Ménière’s disease

The membranous labyrinth is a structure located within the otic capsule, consisting of a set of vesicles and ducts containing endolymph, which form a closed fluid circulation system separated from the surrounding perilymph. Endolymphatic hydrops (HE) is the distension of the endolymphatic compartments of the inner ear into the surrounding perilymphatic space, with involvement of both the cochlea and vestibule, a finding that is considered the pathological hallmark of Ménière’s disease; however, it may also be seen in other otological disorders with similar symptoms. Visualization of HE has been achieved by magnetic resonance imaging with FLAIR sequence optimized for inner ear assessment, performed four hours after injection of intravenous contrast; a method that has become a reliable technique to demonstrate and classify HE. The objective of this iconographic essay is to present, by means of the FLAIR sequence, the normal findings of the labyrinth, as well as the different ways of assessing endolymphatic hydrops, for which cases from our institution were used.