Investigating Arterial Spin Labeling As Large Vessel Correlate of Svd, AD, and PD

Background: In elderly populations, cerebral blood perfusion (CBF) measurements with arterial spin labelling (ASL) are affected by macro-vascular artefacts as a result of prolonged arterial transit time (ATT) [Figure 1]. The spatial coefficient of variance (CoV) provides a robust indirect estimate of ATT, hence it might be used as a proxy of the vascular health of the subject2, alone or in conjunction with other measures such as white matter hyperintensities (WMH) volume. The goal of this study was to compare spatial CoV between healthy controls (HCs) and subjects with Alzheimer’s (AD) or Parkinson’s (PD) disease. Methods: We analysed the scans of 143 participants from the APGeM study, in which a 3D GRASE pulsed ASL protocol was added to the Siemens 3T MRI protocol for degenerative diseases. Healthy controls (HC, n=56) and participants with AD- or PD-related mild cognitive impairment or dementia (AD, n=41; PD, n=46) were included [Table 1]. We calculated grey matter (GM) CBF, spatial CoV, and WMH volume using ExploreASL [ref]. Pearson’s correlation was used to calculate the correlation of spatial CoV with age and WMH volume. Student’s-test was performed to check differences in spatial CoV between sexes. A linear regression model was built to investigate whether spatial CoV could discriminate between HC vs. AD, HC vs. PD, and AD vs. PD after correction for age and sex. WMH and spatial CoV were logtransformed. Results: Spatial CoV showed a positive correlation with age (cor=0.35, p<0.001) and with WMH volume (cor=0.38, p <0.001) [Figure 2]. A difference in spatial CoV of 0.12 was reported (p<0.001). Spatial CoV differences were detected between HC and AD (ß=0.08, p=0.004) and between HC and PD (ß=0.09, p=0.0002) subjects [Figure 3]. However, spatial CoV was not able to discriminate between AD and PD. Conclusions: The relatively strong correlation between spatial CoV and WMH volume make ASL a promising marker to investigate the interplay between large and small vessel