Visualization of endolymphatic hydrops after intratympanic injection of Gd-DTPA: a comparison of high resolution three dimensional-real inversion recovery and three dimensional fluid-attenuated inversion recovery with a variable flip angle sequence

Abstract

Objective To compare the value of high resolution 3D-real inversion recovery(3D-real IR) and 3D fluid-attenuated inversion recovery with a variable flip angle (3D-Flair-VFL) sequence in the visualization of endolymphatic hydrops. Methods 52 ears in 40 patients with Meniere's disease or delayed endolymphatic hydrops were enrolled and performed by axial 3D-real IR and 3D-Flair MRI scans 24 hours after intratympanic injection of eight-fold diluted Gd-DTPA. Signal to noise ratio (SNR) and contrast-to-noise ratio (CNR) of the two sequences were calculated and compared by t test. Whether there were endolymphatic hydrops in the basal turn, middle turn, apical turn of the cochlear and vestibule was further evaluated. Results Both the SNR and CNR of 3D-real IR images were statistically higher than 3D-Flair images (SNR: 28.06±12.71 vs. 17.64±6.38, P<0.05; CNR: 33.79±13.52 vs. 15.40±6.04, P<0.05). Endolymphatic hydrops of the basal turn, second turn, apical turn of the cochlear and vestibule detected by 3D-Flair-VFL images were 33, 37, 10 and 41 cases, respectively, while by 3D-Flair-VFL images were 46, 46, 46 and 49 cases, respectively. There were significant differences between the two sequences in evaluating basal turn, second turn, apical turn of the cochlear except vestibule (P<0.05). Conclusion 3D-real IR images are clearer than 3D-Flair-VFL images and can display endolymphatic hydrops more precisely. Key words: Magnetic resonance imaging; Ear, inner; Meniere disease