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Vasogenic edema in the frontostriatal tract and the anterior limb of the internal capsule predict cognitive decline in Alzheimer disease
Author(s) -
Wang Qing,
Chen Gengsheng,
McKay Nicole Sarah,
Gordon Brian A.,
Hassenstab Jason,
Morris John C.,
Morris John C.,
Benzinger Tammie L.S.,
Wang Yong
Publication year - 2020
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1002/alz.046183
Subject(s) - cognition , internal capsule , white matter , psychology , diffusion mri , medicine , neuroscience , magnetic resonance imaging , radiology
Background Whereas the gray matter has long been regarded by neuroscientists as the major locus of cognitive function, white matter (WM) structures of the brain are increasingly recognized as critical for cognition. In particular, the frontostriatal tract (FST) and the anterior limb of the internal capsule (ALIC) play important roles in cognition function. In order to noninvasively quantify WM integrity, inflammation, and edema, a diffusion‐based MRI method, neuro‐inflammation imaging (NII), has recently been developed and validated. Specifically, NII‐derived extracellular water fraction (NII‐EWF) has been used as a surrogate biomarker of WM vasogenic edema in Alzheimer Disease (AD) (Figure 1). This study aimed to examine: (1) whether NII‐EWF in the FST and the ALIC is associated with cognitive ability; (2) whether the baseline NII‐EWF in the FST and the ALIC predict the cognitive decline in AD. Method 172 Participants (121 amyloid negative healthy controls, 31 amyloid positive individuals w/ normal cognition and 20 individuals diagnosed as AD with a CDR of 0.5) enrolled in ongoing studies at the Knight ADRC at Washington University in Saint Louis underwent NII measures and a test battery of cognitive tests. Our measure of cognitive ability was Trail Making test, which is a subtask within our cognitive battery that assesses visual attention and working memory abilities. NII was acquired with multi‐b value scheme ( bmax =1400s/mm 2 and 25 directions). A random coefficient model was used to assess correlations between NII‐EWF and cognitive measures and to assess whether the baseline NII‐EWF is predictive of cognitive decline. Result The significant correlations between NII‐EWF and cognitive ability has been observed in both the FST (Figure 2A) and the ALIC (Figure 2B). The measure of NII‐EWF in both tracts has been found to be significantly predictive of the rate of cognitive decline (Figure 3). Conclusion Our findings suggest that NII‐EWF could be used as a predictor for cognitive decline in preclinical and early symptomatic AD. Given that the measure is acquired without using contrast agent and radioactive tracer, NII holds great promise as an accessible measure for quantifying WM pathologies and investigating their roles in the cognitive decline in AD.