Arterial Spin Labeling MRI in Alzheimer's Disease: A Systematic Review of Cerebral Perfusion Biomarkers.

backgroundAlzheimer's disease (AD) is a leading cause of dementia. Arterial spin labeling (ASL) MRI, particularly at 3 Tesla (3T), offers a noninvasive method to assess cerebral blood flow alterations, which are believed to be early indicators of AD. PURPOSE: The purpose of this study is to evaluate the utility of 3T ASL MRI in identifying cerebral perfusion biomarkers for the diagnosis and management of AD, assess its prognostic value, and compare it to other imaging modalities, such as PET. DATA SOURCES: A systematic literature search was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines across PubMed, Cochrane Library, and Scopus using keywords related to "ASL," "3T MRI," and "AD." STUDY SELECTION: Studies were included if they used 3T ASL MRI to investigate CBF in AD. Reviews, preclinical studies, case reports, studies lacking 3T ASL MRI, or those focusing on other dementias or mild cognitive impairment without an AD comparison were excluded. Data extracted included study design, sample characteristics, imaging techniques, parameters measured, and outcomes. A qualitative synthesis of findings highlights CBF patterns and biomarkers associated with AD.

resultsFindings demonstrated hypoperfusion in the hippocampus, precuneus, and posterior cingulate cortex, distinguishing AD from normal aging and other forms of dementia. CBF patterns are often correlated with the severity and progression of cognitive impairment. ASL MRI at 3T demonstrated diagnostic accuracy comparable to that of PET while being noninvasive and radiation free.

conclusionASL MRI at 3T could be a valuable tool for the early diagnosis and monitoring of AD. Its noninvasive nature makes it ideal for repeated measures and longitudinal studies. Further research should focus on standardizing protocols and validating their use in larger populations.