Combining optimized three-dimensional ZOOMit real inversion recovery with T2-preparation to shorten the delay interval and scan time for endolymphatic hydrops evaluation in patients with Ménière's disease.

Background: The scan times and delay intervals of three-dimensional real inversion recovery imaging are excessively long, which limits its widespread use in clinical settings. This study aimed to determine whether an optimized three-dimensional zoomed imaging technique with parallel-transmission (ZOOMit) sampling perfection with application-optimized contrasts using different flip-angle evolutions (SPACE) real inversion recovery under T2 preparation protocols could evaluate endolymphatic hydrops with a short delay interval and scan time. Methods: Consecutive participants were recruited for this prospective study. All participants underwent optimized three-dimensional ZOOMit SPACE real inversion recovery with T2 preparation at 2-, 4-, and 6-hour post-administration. The overall image quality, the separation of the endolymph and perilymph, and the grade of endolymphatic hydrops were assessed and compared across each of the three delay intervals. Similarly, the signal intensity ratio (SIR), contrast-to-noise ratio (CNR), and signal-to-noise (SNR) were quantitatively calculated and compared across each of the three delay intervals. Results: The post hoc analyses revealed that the 4-hour-delay interval was superior to the 2-hour-delay interval in terms of overall image quality (P<0.001). Similarly, the 6-hour-delay interval was superior to the 2-hour-delay interval in terms of overall image quality (P<0.001). The 6-hour-delay interval demonstrated superior cochlear endolymph and perilymph separation as compared to the 2-hour-delay interval (P<0.001). Similarly, the 4-hour-delay interval demonstrated superior cochlear endolymph and perilymph separation of the asymptomatic side as compared to the 2-hour-delay interval (P<0.001). The SIR, CNR, and SNR differed significantly across the three postinjection intervals (all P values <0.001). The post hoc analyses revealed that except for the CNRs of the asymptomatic inner ear, the CNRs, SIRs, and SNRs of the optimized three-dimensional ZOOMit SPACE real inversion recovery with T2 preparation sequence were significantly higher at 4 hours than at 2 hours after intravenous administration of gadolinium (IV-Gd) (all pairwise comparison P values <0.001). Meanwhile, the SIRs, CNRs, and SNR were significantly higher at 6 hours than at 2 hours after IV-Gd (pairwise comparison P values <0.001); the CNR, SNR, and affected SIR parameters were also higher at 6 hours than at 4 hours after IV-Gd (pairwise comparison P values <0.001). However, the evaluation of the affected cochlear and vestibular endolymphatic hydrops across the three postinjection intervals did not differ significantly. Conclusions: The optimized three-dimensional ZOOMit SPACE real inversion recovery with T2 preparation sequence at a 2-hour-delay interval and 437-second scan time can reliably evaluate endolymphatic hydrops and blood-labyrinth barrier impairment. These findings contribute to the broader application of this approach in clinical settings.