Agreement between early-phase Amyloid-PET and pulsed Arterial Spin Labeling in a memory clinic cohort

Abstract

Abstract Relative Cerebral Blood Flow (rCBF) as assessed with pulsed Arterial Spin Labeling (pASL) MRI and the standardized uptake value ratio (SUVr) in early-phase amyloid-PET (ePET) can be used as proxies of brain perfusion. Both techniques have shown good agreement with the gold-standard (F-fluorodeoxyglucose-PET), however the comparison between them is less clear. This study aimed to compare perfusion-like data from pASL (rCBF) and ePET (SUVr) in a memory clinic cohort. We included 46 patients (69 ± 8 years; 37 women) from the Geneva Memory Center (Cognitively Impaired-CI n = 29; Cognitively Unimpaired-CU n = 17), with available pASL and ePET. We tested the association between rCBF and SUVr values in 18 cortical/subcortical regions using Pearson’s correlations (r). Regional differences between CU and CI were evaluated using the Mann-Whitney test. We observed weak correlations (0 < r < 0.39) between rCBF and SUVr in: frontal superior, posterior cingulate, precuneus, superior temporal pole, insula, amygdala, caudate, thalamus; moderate correlations (r > 0.40) in: precuneus, hippocampus, putamen. Additionally, significant differences in rCBF between CU and CI were also observed in the inferior temporal, precuneus, and calcarine (p < 0.05), while SUVr showed significantly differences in the hippocampus and caudate between the two clinical groups. The posterior cingulate was the only region consistently different in rCBF and SUVr between CU and CI subjects. Our findings indicate weak to moderate local correlations between the two analyzed techniques. Nevertheless, both techniques exhibited differing regional levels of perfusion in CU and CI groups. Notably, rCBF showed differences mainly in cortical regions, while SUVr differences were predominantly observed in subcortical areas.