| Background:With the aging of the population,the prevalence of dementia is rising rapidly and has become the second largest health problem for adults after cancer.Dementia is the most severe stage of cognitive impairment,and the daily activities of patients are impaired,which brings great burden to patients and their families.At present,there is no cure for dementia,but its proclinical and prodromal course is very long.Early diagnosis and intervention will greatly improve the quality of life of patients.Subjective cognitive decline(SCD)and mild cognitive impairment(MCI)and are the early stages of dementia,and there is a high risk of developing dementia in the future,so it is necessary to pay attention to this population.Cerebral blood flow is very important in all stages of cognitive impairment,especially in the early stage.Arterial spin labeled(ASL)magnetic resonance imaging(MRI)can quantitatively measure CBF,without exogenous tracer,and its reliability has been widely verified.Objective:The CBF of MCI,SCD and normal control(NC)was obtained by ASL-MRI technique,and the relationship between CBF and cognitive function was analyzed,and the feasibility of using ASL-MRI technique to identify predementia was discussed,so as to provide experimental basis for CBF as a biomarker for early diagnosis of cognitive impairment.Objects and methods:196 volunteers were randomly recruited from August 2018 to March 2020,and 169 subjects were finally included in accordance with strict inclusion and exclusion criteria.According to the neuropsychological criteria for MCI proposed by Jak and Bondi and the diagnostic criteria of SCD recommended by Professor Han Ying of Xuanwu Hospital,all subjects were divided into MCI group,SCD group and normal control(NC)group.There were 59 patients in MCI group,26 patients in SCD group and 84 patients in NC group.All subjects recorded basic information and were evaluated with a complete set of neuropsychological scales.The structural images and ASL functional images of all subjects were collected by German Siemens MAGNETOM Skyra 3.0T magnetic resonance scanner,and then the data were processed.One-way ANOVA was used to compare the differences of CBF among the three groups,and the brain regions of CBF differences between the two groups were obtained by pairwise comparison,and the results were corrected by Alphasim.The CBF values of different brain regions between the groups were extracted,and spearman correlation analysis was conducted between the CBF values and the scores of overall cognition and the three cognitive domains(memory function,executive function,and language function).P<0.05 indicated that the differences were statistically significant.Results:The overall cognitive level,memory function,language function and executive function of the MCI group were significantly worse than those of the NC group(P<0.05).The overall cognitive level,memory function and language function of the MCI group were significantly worse than those of the SCD group(P<0.05).There was no statistical difference between the NC group and the SCD group in each cognitive field(P>0.05).There were significant differences in regional CBF among the three groups,and the differences were mainly distributed in the left frontal lobe,left anterior and middle cingulate gyrus,bilateral cuneate lobe and bilateral occipital lobe.Pairwise comparison showed that the CBF in left frontal lobe,left anterior and middle cingulate gyrus,bilateral precuneus lobe and bilateral occipital lobe in MCI group was lower than that in NC group,and the CBF in left frontal lobe and left anterior and middle cingulate gyrus in MCI group was lower than that in SCD group.There was no significant difference in CBF between SCD group and NC group.Correlation analysis showed that the executive function of MCI group was positively correlated with CBF of right lingual gyrus.(P=0.014,rs=0.319).Conclusion:1.MCI patients mainly showed low perfusion in anterior and middle cingulate gyrus,precuneate lobe,occipital lobe and frontal lobe,while no obvious abnormal perfusion was found in all brain regions of SCD patients.2.Low occipital perfusion may be related to executive dysfunction.3.The measurement of CBF by ASL-MRI technique is reliable,and CBF may be used as a biomarker for early diagnosis of cognitive impairment. |
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