Quantifying the effects of normal ageing on white matter structure using unsupervised tract shape modelling
Quantifying the effects of normal ageing on white matter structure using unsupervised tract shape modelling
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DOI：
10.1016/j.neuroimage.2010.02.036
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发表时间：
2010-05-15
期刊：
影响因子：
5.7
通讯作者：
Clayden, Jonathan D.
中科院分区：
文献类型：
--
作者：
Bastin, Mark E.;Maniega, Susana Munoz;Clayden, Jonathan D.
定量纤维束造影术可提供对正常衰老中白质结构变化的区域性异质性的洞察。在这里，我们使用增强版本的概率邻域脑束成像技术，在90名65岁以上的非痴呆受试者中，研究脑萎缩和白质病变如何影响额叶和非额叶一系列脑束形状、脑束完整性和年龄之间的相关性。这种用于自动放置单个种子点的新方法使用无监督学习和流线选择来提供可靠和准确的束分割，同时还指示单个束的形状如何与预定义的参考束的形状相比较。年轻脑白质图谱的束形态相似性与膝部和压部的年龄呈显著负相关。控制颅内和侧脑室容量，后者随着年龄的增加而显著增加，分别减弱了40%和84%的相关性，表明这种与年龄相关的膝盖束拓扑结构的变化明显地由整体萎缩和脑室扩大所介导。根据“额叶老化”假说，膝骨体的平均弥散率(<；D>；)与年龄呈显著正相关，而分数各向异性(FA)与年龄呈显著负相关：压部未见相关关系。双侧扣带回、扣带束和右侧皮质脊髓束的<；D和gt；与年龄呈显著正相关。然而，当对那些有显著白质损伤负荷的受试者和那些没有白质损伤负荷的受试者进行单独分析时，这种相关性模式并没有重现。因此，这些数据表明，脑萎缩和白质损伤在驱动与年龄相关的白质束形状和完整性变化的区域模式中发挥着重要作用。(C)2010 Elsevier Inc.保留所有权利。
Quantitative tractography may provide insights into regional heterogeneity of changes in white matter structure in normal ageing. Here we examine how brain atrophy and white matter lesions affect correlations between tract shape, tract integrity and age in a range of frontal and non-frontal tracts in 90 non-demented subjects aged over 65 years using an enhanced version of probabilistic neighbourhood tractography. This novel method for automatic single seed point placement employs unsupervised learning and streamline selection to provide reliable and accurate tract segmentation, whilst also indicating how the shape of an individual tract compares to that of a predefined reference tract. There were significant negative correlations between tract shape similarity to reference tracts derived from a young brain white matter atlas and age in genu and splenium of corpus callosum. Controlling for intracranial and lateral ventricle volume, the latter of which increased significantly with age, attenuated these correlations by 40% and 84%, respectively, indicating that this age-related change in callosal tract topology is significantly mediated by global atrophy and ventricular enlargement. In accordance with the "frontal ageing" hypothesis, there was a significant positive correlation between mean diffusivity (< D >) and age, and a significant negative correlation between fractional anisotropy (FA) and age in corpus callosum genii: correlations not seen in splenium. Significant positive correlations were also observed between < D > and age in bilateral cingulum cingulate gyri, uncinate fasciculi and right corticospinal tract. This pattern of correlations was not, however, reproduced when those subjects with significant white matter lesion load were analyzed separately from those without. These data therefore suggest that brain atrophy and white matter lesions play a significant role in driving regional patterns of age-related changes in white matter tract shape and integrity. (C) 2010 Elsevier Inc. All rights reserved.