Naganawa Shinji, Ito Rintaro, Kawamura Mariko, Taoka Toshiaki, Yoshida Tadao, Sone Michihiko
Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.
Department of Otorhinolaryngology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.
Magn Reson Med Sci. 2025 Apr 1;24(2):253-261. doi: 10.2463/mrms.mp.2024-0011. Epub 2024 Apr 3.
The endolymph of the inner ear, vital for balance and hearing, has long been considered impermeable to intravenously administered gadolinium-based contrast agents (GBCAs) due to the tight blood-endolymph barrier. However, anecdotal observations suggested potential GBCA entry in delayed heavily T2-weighted 3D-real inversion recovery (IR) MRI scans. This study systematically investigated GBCA distribution in the endolymph using this 3D-real IR sequence.
Forty-one patients suspected of endolymphatic hydrops (EHs) underwent pre-contrast, 4-h, and 24-h post-contrast 3D-real IR imaging. Signal intensity in cerebrospinal fluid (CSF), perilymph, and endolymph was measured and analyzed for temporal dynamics of GBCA uptake, correlations between compartments, and the influence of age and presence of EH.
Endolymph showed a delayed peak GBCA uptake at 24h, contrasting with peaks in perilymph and CSF at 4h. Weak to moderate positive correlations between endolymph and CSF contrast effect were observed at both 4 (r = 0.483) and 24h (r = 0.585), suggesting possible inter-compartmental interactions. Neither the presence of EH nor age significantly influenced endolymph enhancement. However, both perilymph and CSF contrast effects significantly correlated with age at both time points.
This study provides the first in vivo systematic confirmation of GBCA entering the endolymph following intravenous administration. Notably, endolymph uptake peaked at 24h, significantly later than perilymph and CSF. The lack of a link between endolymph contrast and both perilymph and age suggests distinct uptake mechanisms. These findings shed light on inner ear fluid dynamics and their potential implications in Ménière's disease and other inner ear disorders.
内耳内淋巴液对平衡和听力至关重要，长期以来，由于血 - 内淋巴屏障紧密，人们一直认为静脉注射钆基造影剂（GBCAs）无法渗透到内淋巴液中。然而，一些轶事观察表明，在延迟的重T2加权三维真实反转恢复（IR）MRI扫描中，GBCA可能进入内淋巴液。本研究使用这种三维真实IR序列系统地研究了GBCA在内淋巴液中的分布情况。
41名疑似内淋巴积水（EHs）的患者在注射造影剂前、注射后4小时和24小时接受了三维真实IR成像。测量并分析了脑脊液（CSF）、外淋巴液和内淋巴液中的信号强度，以了解GBCA摄取的时间动态、各腔室之间的相关性以及年龄和EH的存在对其的影响。
内淋巴液在24小时时显示出延迟的GBCA摄取峰值，这与外淋巴液和脑脊液在4小时时的峰值形成对比。在4小时（r = 0.483）和24小时（r = 0.585）时，均观察到内淋巴液与脑脊液对比效应之间存在弱至中度的正相关，表明可能存在腔室间相互作用。EH的存在和年龄对内淋巴液增强均无显著影响。然而，在两个时间点，外淋巴液和脑脊液的对比效应均与年龄显著相关。
本研究首次在体内系统地证实了静脉注射后GBCA进入内淋巴液。值得注意的是，内淋巴液摄取在24小时达到峰值，明显晚于外淋巴液和脑脊液。内淋巴液对比与外淋巴液和年龄之间缺乏关联表明存在不同的摄取机制。这些发现揭示了内耳液动力学及其在梅尼埃病和其他内耳疾病中的潜在意义。
