The effect of delay time after injecting gadobutrol on the diagnosis of endolymphatic hydrops

Objectives: The aim of this study was to reduce the time delay between gadolinium injection and 3D-FLAIR (threedimensional fluid-attenuated inversion recovery) MRI by using a single dose of intravenous gadobutrol in Menie`re's disease patients. Methods: 17 patients diagnosed with definite unilateral Meniere's disease underwent 3D-FLAIR MRI scans at 2, 4, and 6 h post-intravenous administration of a single-dose of gadobutrol. The signal intensity ratio of bilateral inner ear, cochlear and vestibular hydrops was measured at 2 h, 4 h and 6 h, while the differences in signal intensity ratio and endolymphatic hydrops were evaluated at three time points. Results: The cochlea, vestibule, and semicircular canal exhibit clear structural features with distinct perilymphendolymph boundaries at 2 h, 4 h, and 6 h. The signal intensity ratio of the affected ear was significantly higher than that of the unaffected ear at 2 h, 4 h, and 6 h. The signal intensity ratio at 4 h and 6 h in both the affected and unaffected ears was significantly higher than that at 2 h, but there was no significant difference between 4 h and 6 h. Cochlear hydrops and vestibular hydrops show no significant differences at these time points, demonstrating excellent consistency. Conclusions: We have demonstrated that 3D-FLAIR images acquired 2 h after intravenous administration of a single-dose gadobutrol are of high quality and equally effective as those obtained at the conventional 4-h time point for diagnosing endolymphatic hydrops in Menie`re's disease. In clinical practice, the delay time can be safely shortened to 2 h.