To investigate the characteristics of cerebral blood flow (CBF) in Alzheimer's disease (AD) and its relationship with cognitive function by arterial spin labeling magnetic resonance imaging (ASL-MRI).

Thirteen AD patients admitted to Dongzhimen Hospital, Beijing University of Chinese Medicine from September 2020 to March 2021 were included as the AD group; and other 13 cognitively normal subjects with age and gender matched were included as the normal control group. The cortical CBF was measured by ASL-MRI, and their cognitive function was evaluated by neuropsychological scales. The receriver operating characteristic curve was used to evaluate the diagnostic efficacy of CBF value in each brain region for AD, and correlation analysis was used to study the relationship between CBF in different brain regions and cognitive function.

The cerebral blood flow in AD group generally showed decreased compared with the normal control group, especially the cerebral blood flow in the anterior central gyrus, middle frontal gyrus, posterior cingulate gyrus, and left middle temporal lobe [(30.44±8.02) ml/(100 g·min) vs (42.63±12.89) ml/(100 g·min), (29.73±15.70) ml/(100 g·min) vs (47.44±14.30) ml/(100 g·min), (39.69±13.31) ml/(100 g·min) vs (58.84±15.98) ml/(100 g·min), (40.87±14.62) ml/(100 g·min) vs (56.92±16.47) ml/(100 g·min)]. These differences were statistically significant (t=2.410, 2.500, 2.762, 2.186; P=0.028, 0.024, 0.014, 0.044). These areas may be of value in the diagnosis of AD (area under curve = 0.78, 0.80, 0.83, 0.78). CBF of middle frontal gyrus and left posterior cingulate gyrus were positively correlated with MMSE orientation score（r=0.489, 0.511; P=0.040, 0.030）.

CBF in AD patients generally decreased, especially in the middle frontal gyrus and posterior cingulate gyrus, which was related to the score of cognitive function.