ARTERIAL STIFFNESS IS ASSOCIATED WITH GREATER WHITE MATTER BLOOD FLOW AND WHITE MATTER HYPERINTENSITIES REGARDLESS OF COGNITIVE STATUS

Recent developments in arterial spin labeling (ASL) MRI enable more robust measures of cerebral blood flow (CBF) in various regions of the brain including the deep white matter. Arterial stiffness is a marker of excess pulsatile flow associated with cognitive impairment, cerebrovascular disease markers and AD biomarkers. The relationships between arterial stiffness and CBF in the deep white matter remain unknown. Participants (n=144, mean age=71±8 years) underwent clinical and imaging examinations in Clinical Core of the Wake Forest Alzheimer's Disease Center (Table I). 3T brain MRI included T1 MP-RAGE, T2 FLAIR and multiphase pseudo-continuous arterial spin labeling (3.0×3.0×4.0 mm, labeling duration=1700ms, post-labeling delay=1300ms, TR=4000ms, TE=11ms). MP-RAGE and FLAIR were used to calculate AD-signature cortical thickness (by Freesurfer version 5.3) and white matter hyperintensity volume (log transformed WMH divided by ICV (by SPM LST)). Partial volume corrected CBF maps were used to calculated mean whole brain values in gray matter (CBFGM) and white matter (CBFWM) as well as for a voxel-wise analysis.. Arterial stiffness was assessed supine in the fasting state using the Sphygmocor XCEL™ to acquire carotid femoral pulse wave velocity (cfPWV, cm/s). Multivariable general linear models were constructed to examine the relationships between potential covariates, MRI outcomes and cfPWV in adjusted for age and gender. CBFGMand CBFWM were lower in older participants, men, and individuals with dementia. CBFWM was higher among women and African-American participants (p=0.04). Arterial stiffness assessed by cfPWV was associated with greater CBFWM(and WMH (Table II). A voxel-wise analysis of CBF and cfPWV showed a positive correlation between cfPWV and CBFWM. The white matter cluster was located mainly in left temporal and parietal lobes (Figure 1). No associations were observed between cfPWV and CBFGM or AD-signature cortical thickness in this sample. No interactions were detected with race, glycemic status or cognitive status.