Study of brain perfusion in adults with Down syndrome along the Alzheimer’s disease continuum.

We assessed pseudo-continuous arterial spin labeling (pCASL) sensitivity to detect changes in cerebral blood flow (CBF) in adults with Down syndrome (DS) along the Alzheimer’s disease (AD) continuum and explored the similarity with sporadic AD (sAD) hypoperfusion profile. Fifty-one euploid cognitively unimpaired individuals, 54 adults with DS (34.54% symptomatic for AD), and 25 sAD patients underwent 3T magnetic resonance imaging. pCASL images were preprocessed using ASLprep. Analyses explored, globally and regionally, the effects of demographic variables, clinical stages, and AD biomarkers. Age and sex differently impacted CBF in euploids versus the DS population. Asymptomatic DS showed temporo-parietal hypoperfusion, extending into frontal areas in symptomatic cases. This pattern closely resembled sAD’s pattern and correlated with AD biomarkers. Adults with DS present CBF changes before symptom onset, primarily affecting posterior regions as in sAD. pCASL is a sensitive imaging modality that captures early AD-related functional abnormalities in DS. Perfusion is negatively affected by age and correlates with Alzheimer’s disease (AD) biomarkers in Down syndrome (DS). Hypoperfusion in DS was observed even before the onset of the AD clinical symptoms. The pattern of hypoperfusion in the DS population resembles the one observed in the sporadic AD population.