Shahid Beheshti University of Medical Sciences



Alzheimer’s disease (AD) is the most common cause of dementia and the fifth leading cause of death in people aged 65 years and older.
Arterial spin labeling (ASL) is the Non-invasive method that uses arterial blood water as an endogenous tracer to measure cerebral blood flow (CBF).
Arterial spin labeling (ASL) MR imaging is a Non-invasive, rapid and increasingly widely available method for quantifying cerebral blood flow; ASL represents a potential alternative modality for measuring brain perfusion as compared with positron emission tomography (PET).
Quantitative imaging of cerebral blood flow, using standard magnetic resonance imaging (MRI) equipment because it requires no contrast injection, ASL can add resting functional information to MRI studies measuring atrophy and signs of ischemic injury. Key features of ASL technology that may affect studies in Alzheimer’s Disease are described. 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.
The most consistent finding across the studies of AD is decreased precuneus and/or posterior cingulate blood flow and lower posterior CBF at the time of diagnosis show a more rapid cognitive decline. Some of the regions with the slowest arrival are those that also show flow decreases in AD, such as parietal and frontal association cortex.
Since MRI scanners are more widely available than PET scanners (and also less expensive), ASL might become an alternative for FDG-PET.
ASL blood flow MRI is a promising marker of early disease in AD and other dementias. ASL currently lags some other imaging methods in the maturity of the technology and the evaluation in AD. With widespread distribution of the technique in progress, we anticipate these challenges will shortly be overcome and ASL will become an essential tool in AD treatment and prevention research.