Faizy Tobias D, Thaler Christian, Broocks Gabriel, Flottmann Fabian, Leischner Hannes, Kniep Helge, Nawabi Jawed, Schön Gerhard, Stellmann Jan-Patrick, Kemmling André, Reddy Ravinder, Heit Jeremy J, Fiehler Jens, Kumar Dushyant, Hanning Uta
Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
Institute of Applied Biometrics and Epidemiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
Front Neurosci. 2020 Feb 24;14:136. doi: 10.3389/fnins.2020.00136. eCollection 2020.
Quantitative MRI modalities, such as diffusion tensor imaging (DTI) or magnetization transfer imaging (MTI) are sensitive to the neuronal effects of aging of the cerebral white matter (WM), but lack the specificity for myelin content. Myelin water imaging (MWI) is highly specific for myelin and may be more sensitive for the detection of changes in myelin content inside the cerebral WM microstructure. In this multiparametric imaging study, we evaluated the performance of myelin water fraction (MWF) estimates as a marker for myelin alterations during normal-aging. Multiparametric MRI data derived from DTI, MTI and a novel, recently-proposed MWF-map processing and reconstruction algorithm were acquired from 54 healthy subjects (aged 18-79 years) and region-based multivariate regression analysis was performed. MWFs significantly decreased with age in most WM regions (except corticospinal tract) and changes of MWFs were associated with changes of radial diffusivity, indicating either substantial alterations or preservation of myelin content in these regions. Decreases of fractional anisotropy and magnetization transfer ratio were associated with lower MWFs in commissural fiber tracts only. Mean diffusivity had no regional effects on MWF. We conclude that MWF estimates are sensitive for the assessment of age-related myelin alterations in the cerebral WM of normal-aging brains.
定量磁共振成像模态，如扩散张量成像（DTI）或磁化传递成像（MTI），对脑白质（WM）衰老的神经元效应敏感，但对髓鞘含量缺乏特异性。髓鞘水成像（MWI）对髓鞘具有高度特异性，并且可能对检测脑WM微结构内髓鞘含量的变化更敏感。在这项多参数成像研究中，我们评估了髓鞘水分数（MWF）估计值作为正常衰老过程中髓鞘改变标志物的性能。从54名健康受试者（年龄18 - 79岁）获取了源自DTI、MTI以及一种新提出的MWF图处理和重建算法的多参数MRI数据，并进行了基于区域的多变量回归分析。在大多数WM区域（除皮质脊髓束外），MWF随年龄显著降低，并且MWF的变化与径向扩散率的变化相关，表明这些区域髓鞘含量有实质性改变或保持不变。仅在连合纤维束中，各向异性分数和磁化传递率的降低与较低的MWF相关。平均扩散率对MWF没有区域影响。我们得出结论，MWF估计值对评估正常衰老大脑脑WM中与年龄相关的髓鞘改变敏感。
