Magnetic resonance imaging in Ménière´s disease

Abstract

Ménière´s disease (MD) is a known cause of chronic vertigo, with multiple fluctuating audiological symptoms (hearing loss, tinnitus, aural fullness). The pathophysiology is not completely understood but has been attributed to endolymphatic hydrops (EH). There are many electrophysiological tests available, but none of them can be considered as the gold standard, either because of difficult technique or inconsistent results in the literature. Nonetheless, some findings are highly suggestive of MD, like the presence of a low response and high threshold in ocular and cervical VEMPs (vestibular evoked myogenic potentials), or the increased ratio between the amplitudes of summation potential and action potential in the electrocochleography.  Despite the availability of these tests, the diagnosis of MD is still made clinically, following the diagnostic criteria establish by international consensus, due to the difficulty to visualize the EH and also the lack of full comprehension of other pathophysiological mechanisms. In the last decades, there have been promising advances in the detection of endolymphatic hydrops with magnetic resonance imaging, allowing the visualization of the perilymphatic and endolymphatic space using gadolinium as a contrast agent. At the same time, the imaging sequences have improved, new techniques for imaging processing have been developed, entailing that various classifications or graduation systems for EH have been proposed, which will be review in detail, in this paper.