Dept. Medical Physics and Biomedical Engineering, University College London, United Kingdom; School of Biomedical Engineering and Imaging Sciences, Kings College London, United Kingdom.
School of Biomedical Engineering and Imaging Sciences, Kings College London, United Kingdom.
Neuroimage. 2021 Aug 15;237:118112. doi: 10.1016/j.neuroimage.2021.118112. Epub 2021 May 1.
The preterm brain has been analysed after birth by a large body of neuroimaging studies; however, few studies have focused on white matter alterations in preterm subjects beyond infancy, especially in individuals born at extremely low gestation age - before 28 completed weeks. Neuroimaging data of extremely preterm young adults are now available to investigate the long-term structural alterations of disrupted neurodevelopment. We examined white matter hierarchical organisation and microstructure in extremely preterm young adults. Specifically, we first identified the putative hubs and peripheral regions in 85 extremely preterm young adults and compared them with 53 socio-economically matched and full-term born peers. Moreover, we analysed Fractional Anisotropy (FA), Mean Diffusivity (MD), Neurite Density Index (NDI), and Orientation Dispersion Index (ODI) of white matter in hubs, peripheral regions, and over the whole brain. Our results suggest that the hierarchical organisation of the extremely preterm adult brain remains intact. However, there is evidence of significant alteration of white matter connectivity at both the macro- and microstructural level, with overall diminished connectivity, reduced FA and NDI, increased MD, and comparable ODI; suggesting that, although the spatial configuration of WM fibres is comparable, there are less WM fibres per voxel. These alterations are found throughout the brain and are more prevalent along the pathways between deep grey matter regions, frontal regions and cerebellum. This work provides evidence that white matter abnormalities associated with the premature exposure to the extrauterine environment not only are present at term equivalent age but persist into early adulthood.
大量神经影像学研究对早产儿出生后的大脑进行了分析；然而，很少有研究关注早产儿在婴儿期之后的白质变化，尤其是在出生极早早产儿（胎龄 28 周前）中。目前已有大量神经影像学数据可用于研究神经发育中断的长期结构变化。我们研究了极早早产青年的大脑白质的层次组织和微观结构。具体来说，我们首先在 85 名极早早产青年中确定了潜在的中枢和外周区域，并将其与 53 名社会经济状况匹配且足月出生的同龄人进行了比较。此外，我们还分析了中枢、外周区域以及整个大脑的分数各向异性（FA）、平均扩散系数（MD）、神经丝密度指数（NDI）和各向异性指数（ODI）。我们的结果表明，极早早产成人大脑的层次组织仍然完整。然而，有证据表明，白质连接在宏观和微观结构层面都存在显著变化，整体连接减少，FA 和 NDI 降低，MD 增加，ODI 相似；这表明，尽管 WM 纤维的空间配置是可比的，但每个体素的 WM 纤维数量减少。这些变化在整个大脑中都存在，并且在深灰质区域、额叶区域和小脑之间的通路中更为常见。这项工作提供了证据，表明与早产相关的白质异常不仅在足月等效年龄存在，而且会持续到成年早期。
