ASL-vascular insufficiency parameters can differentiate healthy controls from Alzheimer’s and Parkinson’s diseases

Decreased/Poor vascular health - e.g. increased vascular resistance, tortuosity - may lead to a delayed arrival of labelled blood to brain tissue causing vascular artefacts on arterial spin labeling (ASL) images [Figure 1]. Although these artefacts are traditionally treated as a nuisance, their presence can be quantified by the spatial coefficient of variance (CoV) parameter and used as an indication of vascular insufficiency. . Here, the goal was to investigate the ability of spatial CoV to assess the vascular health by comparing it between healthy controls and subjects with Alzheimer’s (AD) and Parkinson’s (PD) diseases.

Methods: We analyzed the MRI scans of 143 APGeM study participants, including healthy controls (HC, n=56) and subjects with AD- (n=41) or PD-related (n=46) mild cognitive impairment or dementia [Table]. We calculated CBF, spatial CoV, and WMH volume using ExploreASL [ref]. Pearson’s correlations of spatial CoV with age and WMH volume were investigated, as well as a t-test for the relation between spatial CoV and sex. A linear regression model was used to evaluate whether spatial CoV was able to discriminate HC vs. AD, HC vs. PD, and AD vs. PD after correction for age and sex.

Results: Spatial CoV measures showed a positive correlation with age (cor=0.35, p <0.001 and with WMH volume (cor=0.38, p <0.001 [Figure 2A], and differed between sexes (p <0.001). Differences in spatial CoV values were detected between HC and AD and between HC and PD subjects (p<0.05 in both cases) [Figure 2B]. With our model, spatial CoV was not able to discriminate between AD and PD.

Conclusions: These findings suggest that spatial CoV can provide insight in the vascular component of AD and PD pathologies. Validation of these results in larger cohorts and across a wider range of disorders might provide further insight in the relation between cerebrovascular health and neurodegeneration.