Altered whole-brain white matter networks in preclinical Alzheimer's disease

Surrogates of whole-brain white matter (WM) networks reconstructed using diffusion tensor imaging (DTI) are novel markers of structural brain connectivity. Global connectivity of networks has been found impaired in clinical Alzheimer's disease (AD) compared to cognitively healthy aging. We hypo...

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Main Authors: Florian Udo Fischer, Dominik Wolf, Armin Scheurich, Andreas Fellgiebel
Format: Article
Language:English
Published: Elsevier 2015-01-01
Series:NeuroImage: Clinical
Subjects:
DTI
Online Access:http://www.sciencedirect.com/science/article/pii/S2213158215001138
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spelling doaj-246412008b0c406e9abdbbd77535dcf72020-11-24T21:40:04ZengElsevierNeuroImage: Clinical2213-15822015-01-018C66066610.1016/j.nicl.2015.06.007Altered whole-brain white matter networks in preclinical Alzheimer's diseaseFlorian Udo FischerDominik WolfArmin ScheurichAndreas FellgiebelSurrogates of whole-brain white matter (WM) networks reconstructed using diffusion tensor imaging (DTI) are novel markers of structural brain connectivity. Global connectivity of networks has been found impaired in clinical Alzheimer's disease (AD) compared to cognitively healthy aging. We hypothesized that network alterations are detectable already in preclinical AD and investigated major global WM network properties. Other structural markers of neurodegeneration typically affected in prodromal AD but seeming largely unimpaired in preclinical AD were also examined. 12 cognitively healthy elderly with preclinical AD as classified by florbetapir-PET (mean age 73.4 ± 4.9) and 31 age-matched controls without cerebral amyloidosis (mean age 73.1 ± 6.7) from the ADNI were included. WM networks were reconstructed from DTI using tractography and graph theory. Indices of network capacity and the established imaging markers of neurodegeneration hippocampal volume, and cerebral glucose utilization as measured by fludeoxyglucose-PET were compared between the two groups. Additionally, we measured surrogates of global WM integrity (fractional anisotropy, mean diffusivity, volume). We found an increase of shortest path length and a decrease of global efficiency in preclinical AD. These results remained largely unchanged when controlling for WM integrity. In contrast, neither markers of neurodegeneration nor WM integrity were altered in preclinical AD subjects. Our results suggest an impairment of WM networks in preclinical AD that is detectable while other structural imaging markers do not yet indicate incipient neurodegeneration. Moreover, these findings are specific to WM networks and cannot be explained by other surrogates of global WM integrity.http://www.sciencedirect.com/science/article/pii/S2213158215001138Preclinical Alzheimer's diseaseDTIBrain network
collection DOAJ
language English
format Article
sources DOAJ
author Florian Udo Fischer
Dominik Wolf
Armin Scheurich
Andreas Fellgiebel
spellingShingle Florian Udo Fischer
Dominik Wolf
Armin Scheurich
Andreas Fellgiebel
Altered whole-brain white matter networks in preclinical Alzheimer's disease
NeuroImage: Clinical
Preclinical Alzheimer's disease
DTI
Brain network
author_facet Florian Udo Fischer
Dominik Wolf
Armin Scheurich
Andreas Fellgiebel
author_sort Florian Udo Fischer
title Altered whole-brain white matter networks in preclinical Alzheimer's disease
title_short Altered whole-brain white matter networks in preclinical Alzheimer's disease
title_full Altered whole-brain white matter networks in preclinical Alzheimer's disease
title_fullStr Altered whole-brain white matter networks in preclinical Alzheimer's disease
title_full_unstemmed Altered whole-brain white matter networks in preclinical Alzheimer's disease
title_sort altered whole-brain white matter networks in preclinical alzheimer's disease
publisher Elsevier
series NeuroImage: Clinical
issn 2213-1582
publishDate 2015-01-01
description Surrogates of whole-brain white matter (WM) networks reconstructed using diffusion tensor imaging (DTI) are novel markers of structural brain connectivity. Global connectivity of networks has been found impaired in clinical Alzheimer's disease (AD) compared to cognitively healthy aging. We hypothesized that network alterations are detectable already in preclinical AD and investigated major global WM network properties. Other structural markers of neurodegeneration typically affected in prodromal AD but seeming largely unimpaired in preclinical AD were also examined. 12 cognitively healthy elderly with preclinical AD as classified by florbetapir-PET (mean age 73.4 ± 4.9) and 31 age-matched controls without cerebral amyloidosis (mean age 73.1 ± 6.7) from the ADNI were included. WM networks were reconstructed from DTI using tractography and graph theory. Indices of network capacity and the established imaging markers of neurodegeneration hippocampal volume, and cerebral glucose utilization as measured by fludeoxyglucose-PET were compared between the two groups. Additionally, we measured surrogates of global WM integrity (fractional anisotropy, mean diffusivity, volume). We found an increase of shortest path length and a decrease of global efficiency in preclinical AD. These results remained largely unchanged when controlling for WM integrity. In contrast, neither markers of neurodegeneration nor WM integrity were altered in preclinical AD subjects. Our results suggest an impairment of WM networks in preclinical AD that is detectable while other structural imaging markers do not yet indicate incipient neurodegeneration. Moreover, these findings are specific to WM networks and cannot be explained by other surrogates of global WM integrity.
topic Preclinical Alzheimer's disease
DTI
Brain network
url http://www.sciencedirect.com/science/article/pii/S2213158215001138
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AT andreasfellgiebel alteredwholebrainwhitematternetworksinpreclinicalalzheimersdisease
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