Observation of contrast enhancement in the cochlear fluid space of healthy subjects using a 3D-FLAIR sequence at 3 Tesla.

Abstract

In animals, the enhancement of perilymph in the cochlea has been reported using 1.25 mmol/kg of Gd-DTPA, allowing the separate visualisation of perilymph and endolymph for the diagnosis of Meniere's disease. The purpose of this study was three-fold: (1) to determine the optimal timing for detecting cochlear fluid enhancement using 3D-FLAIR (fluid-attenuated inversion recovery) after intravenous administration of 0.1 mmol/kg of Gd-DTPA in healthy human subjects; (2) to examine the reliability of enhancement in multiple healthy subjects; and (3) to investigate whether endolymph and perilymph space can be visually discriminated. In two healthy subjects, 3D-FLAIR images were obtained before, immediately after and 2 h, 4 h and 6 h after the injection. Three more healthy subjects were scanned before and 4 h after the injection. In all four ears of the initial two subjects, cochlear fluid was found to be most intensely enhanced 4 h after the injection. In all of the additional three subjects, the cochlear fluid signal had increased after 4 h from injection. However, visual differentiation of endolymph and perilymph fluid could not be achieved. Using 3D-FLAIR and Gd-DTPA, cochlear fluid enhancement can be observed in healthy human ears, even with a single dose of contrast-medium injection.