title: Early detection of microstructural white matter changes associated with arterial pulsatility.
abstract: Increased cerebral blood flow pulsatility is common in vascular dementia and is associated with macrostructural damage to cerebral white matter or leukoaraiosis (LA). In this study, we examine whether cerebral blood flow pulsatility is associated with macrostructural and microstructural changes in cerebral white matter in older adults with no or mild LA and no evidence of dementia. Diffusion Tensor Imaging was used to measure fractional anisotropy (FA), an index of the microstructural integrity of white matter, and radial diffusivity (RaD), a measure sensitive to the integrity of myelin. When controlling for age, increased arterial pulsation was associated with deterioration in both measures of white matter microstructure but not LA severity. A stepwise multiple linear regression model revealed that arterial pulsatility index was the strongest predictor of FA (R = 0.483, adjusted R (2) = 0.220), followed by LA severity, but not age. These findings suggest that arterial pulsatility may provide insight into age-related reduction in white matter FA. Specifically, increased arterial pulsatility may increase perivascular shear stress and lead to accumulation of damage to perivascular oligodendrocytes, resulting in microstructural changes in white matter and contributing to proliferation of LA over time. Changes in cerebral blood flow pulsatility may therefore provide a sensitive index of white matter health that could facilitate the early detection of risk for perivascular white matter damage and the assessment of the effectiveness of preventative treatment targeted at reducing pulsatility.
authors.affiliation: Functional Neuroimaging Laboratory, Faculty of Science and IT, School of Psychology, University of Newcastle Newcastle, NSW, Australia ; Centre for Translational Neuroscience and Mental Health Research, University of Newcastle Newcastle, NSW, Australia ; Hunter Medical Research Institute Newcastle, NSW, Australia.
authors.forename: Todd A D
authors.initials: TA
authors.lastname: Jolly
authors.forename: Grant A
authors.initials: GA
authors.lastname: Bateman
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Levi
authors.forename: Mark W
authors.initials: MW
authors.lastname: Parsons
authors.forename: Patricia T
authors.initials: PT
authors.lastname: Michie
authors.forename: Frini
authors.initials: F
authors.lastname: Karayanidis
keywords: arterial pulsatility; diffusion tensor imaging; fractional anisotropy; leukoaraiosis; pulse wave encephalopathy