Open AccessNonparenchymal fluid is the source of increased mean diffusivity in preclinical Alzheimer's disease
Author(s) -
Sepehrband Farshid,
Cabeen Ryan P.,
Barisano Giuseppe,
SheikhBahaei Nasim,
Choupan Jeiran,
Law Meng,
Toga Arthur W.
Publication year - 2019
Publication title -
alzheimer's and dementia: diagnosis, assessment and disease monitoring
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.497
H-Index - 37
ISSN - 2352-8729
DOI - 10.1016/j.dadm.2019.03.002
Subject(s) - white matter , perivascular space , magnetic resonance imaging , interstitial fluid , diffusion mri , pathology , parenchyma , cognitive decline , hyperintensity , cerebrospinal fluid , thermal diffusivity , pathological , pathophysiology , medicine , disease , dementia , radiology , physics , quantum mechanics
Although increased mean diffusivity of the white matter has been repeatedly linked to Alzheimer's disease pathology, the underlying mechanism is not known. Methods Here, we used ADNI‐3 multishell diffusion magnetic resonance imaging data to separate the diffusion signal of the parenchyma from less hindered fluid pools within the white matter such as perivascular space fluid and fluid‐filled cavities. Results We found that the source of the pathological increase of the mean diffusivity is the increased nonparenchymal fluid, often found in lacunes and perivascular spaces. In this cohort, the cognitive decline was significantly associated with the fluid increase and not with the microstructural changes of the white matter parenchyma itself. The white matter fluid increase was dominantly observed in the sagittal stratum and anterior thalamic radiation. Discussion These findings are positive steps toward understanding the pathophysiology of white matter alteration and its role in the cognitive decline.