Visualization of Endolymphatic Hydrops in Patients With Meniere's Disease

TLDR

Recent reports describe intratympanic gentamicin and steroid therapies for Meniere’s disease and sudden sensorineural hearing loss. The study aimed to visualize intratympanic drug entry into the inner ear and to explore its relationship with functional tests and implications for drug‑therapy development. Gadolinium hydrate diluted eightfold with saline was injected intratympanically through the tympanic membrane using a 23‑G needle, and 3‑Tesla 3D‑FLAIR MRI was used to image the inner ear. 3D‑FLAIR MRI showed gadolinium entering the perilymphatic space, delineating perilymphatic and endolymphatic compartments; in patients with endolymphatic hydrops the perilymphatic space was reduced or absent; gadolinium appeared first in the scala tympani and vestibular perilymph, spread throughout perilymph within one day, and largely disappeared after six days, representing the first visualization of endolymphatic hydrops in Meniere’s disease.

Abstract

Recently, there have been many reports of intratympanic gentamicin therapy for the treatment of intractable Meniere's disease. Intratympanic administration of steroids has also been used to treat sudden sensorineural hearing loss. We attempted to visualize how the intratympanically administered drug enters the inner ear.Gadolinium hydrate diluted eightfold with saline was injected intratympanically through the tympanic membrane using a 23 G needle in nine patients with inner ear diseases. With a 3 Tesla magnetic resonance imaging (MRI) unit, three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) imaging was performed.3D-FLAIR MRI clearly revealed that the gadolinium entered the perilymphatic space and delineated the perilymphatic and endolymphatic spaces of the inner ear. In patients with endolymphatic hydrops, the perilymphatic space surrounding the endolymph was small or had disappeared. Gadolinium appeared first in the scala tympani of the basal turn of the cochlea and the perilymphatic space of the vestibule. One day after the intratympanic injection of gadolinium, the gadolinium was observed in almost all parts of the perilymph. Six days after the intratympanic injection, the gadolinium had almost disappeared from the inner ear.We reported the first visualization of endolymphatic hydrops in patients with Meniere's disease. The relationship between the image of the endolymphatic space and functional tests, such as electrocochleography and vestibular-evoked myogenic potential, must be examined in the near future. It is important for the development of intratympanic drug therapies for inner-ear diseases to investigate how the drugs enter and leave the inner ear.