Cerebral blood flow measured by arterial spin labeling MRI at resting state in normal aging and Alzheimer's disease

- ASL MRI is a noninvasive method to quantitatively measure cerebral blood flow.
- Technical advances and multivariate statistical analysis improve ASL investigations.
- Cerebral blood flow changes in aging vary depending on vascular and AD risk factors.
- ASL is promising to use in early diagnosis and monitoring disease progression in AD.

Arterial spin labeling (ASL) magnetic resonance imaging uses arterial blood water as an endogenous tracer to measure cerebral blood flow (CBF). In this review, based on ASL studies in the resting state, we discuss state-of-the-art technical and data processing improvements in ASL, and ASL CBF changes in normal aging, mild cognitive impairment (MCI), Alzheimer's disease (AD), and other types of dementia. We propose that vascular and AD risk factors should be considered when evaluating CBF changes in aging, and that other validated biomarkers should be used as inclusion criteria or covariates when evaluating CBF changes in MCI and AD. With improvements in hardware and experimental design, ASL is proving to be an increasingly promising tool for exploring pathogenetic mechanisms, early detection, monitoring disease progression and pharmacological response, and differential diagnosis of AD.