Show simple item record

NeuroImage

dc.contributor.authorBastin, Mark
dc.contributor.authorMunoz Maniega, Susana
dc.contributor.authorFerguson, Karen J
dc.contributor.authorBrown, Laura J
dc.contributor.authorWardlaw, Joanna M
dc.contributor.authorMacLullich, Alasdair M
dc.contributor.authorClayden, Jonathan D
dc.date.accessioned2011-01-17T14:15:07Z
dc.date.available2011-01-17T14:15:07Z
dc.date.issued2010-05
dc.identifier.issn1053-8119en
dc.identifier.urihttp://dx.doi.org/10.1016/j.neuroimage.2010.02.036en
dc.identifier.urihttp://hdl.handle.net/1842/4597
dc.description.abstractQuantitative 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 genu; 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.en
dc.language.isoenen
dc.publisherElsevieren
dc.subjectageingen
dc.subjectwhite matteren
dc.subjectmagnetic resonance imagingen
dc.subjectwater diffusion tensoren
dc.subjecttractographyen
dc.titleQuantifying the Effects of Normal Ageing on White Matter Structure using Unsupervised Tract Shape Modellingen
dc.typeArticleen
dc.identifier.doi10.1016/j.neuroimage.2010.02.036en
rps.issue1en
rps.volume51en
rps.titleNeuroImageen
dc.extent.pageNumbers1-10en
dc.date.updated2011-01-17T14:15:07Z


Files in this item

This item appears in the following Collection(s)

Show simple item record