Imaging Endolymphatic Hydrops at 3 Tesla Using 3D-FLAIR with Intratympanic Gd-DTPA Administration

Abstract

Purpose: Visualization of endolymphatic hydrops by 3-dimensional fluid-attenuated inversion recovery-FLAIR using conventional turbo-spin-echo (3D-FLAIR-CONV) after intratympanic injection of Gd-DTPA has been reported in patients with Ménière's disease. Compared to 3D-FLAIR-CONV used in previous studies, the addition of a variable flip-angle technique (3D-FLAIR-VFL) enables very long echo trains and, therefore, shorter scan times. We evaluated whether 3D-FLAIR-VFL could replace 3D-FLAIR-CONV in detecting endolymphatic hydrops after intratympanic Gd-DTPA administration. Methods: Eleven patients were included in this study. Twenty-four hours after Gd-DTPA injection, we performed 3D-FLAIR-CONV and 3D-FLAIR-VFL imaging at 3T. We compared the contrast-to-noise ratio (CNR) between cochlear fluid and the cerebellum between the 2 FLAIR sequences. We subjectively scored the size of the endolymphatic space in the cochlea and vestibule for each patient and correlated the scores with the clinical diagnoses. Results: The CNR of 3D-FLAIR-CONV was significantly higher than that of 3D-FLAIR-VFL. Scores for the size of endolymphatic space in the vestibule were identical between the 2 sequences; however, those in the cochlea disagreed in 3 cases. 3D-FLAIR-CONV correlated better with the clinical diagnoses. Conclusions: Currently, we may not be able to replace 3D-FLAIR-CONV with 3D-FLAIR-VFL, at least not with the scanning parameters used in the present study.