Study On The Characteristics Of The Multi Modality Functional Magnetic Resonance Imaging In The Hippocampus Of The Patients With Amnestic Mild Cognitive Impairment

ObjectiveTo compare and analyze the clinical application value of 3D pseudo-continuous arterial spin labeling?3D-PCASL?imaging,multiple b value diffusion weighted imaging?MB-DWI?and ¹H-magnetic resonance spectroscopy?¹H-MRS?for evaluating changes of bilateral hippocampus perfusion and related metabolites of patients with amnestic mild cognitive impairment.Materials and MethodsBased on diagnostic criteria and exclusion criteria,27 patients who visited the Neurology Department of Qianfoshan Hospital Affiliated to Shandong University from February 2015 to December 2016 with complaints of memory loss were enrolled in this study,and 25 elderly cognitively normal people were recruited,the two groups being matched in the following aspects,such as age,gender and education etc.Firstly,all the patients underwent conventional magnetic resonance sequences and magnetic resonance angiography to eliminate cognitive impairment caused by organic disease and cerebrovascular disease,then all the patients underwent 3D-PCASL,MB-DWI and¹H-MRS.Bilateral hippocampus areas were selected as regions of interest and local cerebral blood flow(rCBF_ASL)were measured by 3D-PCASL.The multiple perfusion-related parameters measured by MB-DWI were fast ADC-mono,fraction of fast ADC-mono,fast ADC-bi,and fraction of fast ADC-bi,the multiple diffusion-related parameters of hippocampus?slow ADC-mono,slow ADC-bi?were measured by using parameter maps progressing from mono-exponential,biexponential,and stretched model of multiple b values DWI.Documenting the ratios of N-acetyl aspartate/creatine?NAA/Cr?,myoinositol/creatine?MI/Cr?,and choline/creatine?Cho/Cr?in the bilateral hippocampus,then the differences of ratios between the two groups were compared.T test was performed for bilateral hippocampus areas between aMCI group and NC group.Pearson correlation analysis was performed for changes of relative values?fast ADC-mono,fraction of fast ADC-mono,fast ADC-bi,and fraction of fast ADC-bi?of parameters of MB-DWI and rCBF_ASL.ResultsThe rCBF_ASL of aMCI group was lower than that of NC group and the difference was significant?P<0.05?.The differences of fast ADC-mono,fraction of fast ADC-mono and fraction of fast ADC-bi between aMCI group and NC group were significant?P<0.05?.The fast ADC-bi of aMCI group was lower than that of NC group and the difference was not statistically significant?P>0.05?.The slow ADC-mono and slow ADC-bi of aMCI group was higher than that of NC group,except slow ADC-mono of left hippocampus,the differences of other parameters between two groups were not significant?P<0.05?.The DDC and?of aMCI group were higher than that of NC group,the differences of right hippocampus DDC of and left hippocampus?between two groups were significant?P<0.05?,others weren't.Except fast ADC-bi,the differences between fast ADC-mono,fraction of fast ADC-mono,fraction of fast ADC-bi of bilateral hippocampus areas and rCBF_ASL were statistically significant?P<0.05?.The NAA/Cr ratios and Cho/Cr ratios of the bilateral hippocampus in the aMCI group was lower than those in the control group,except Cho/Cr of left hippocampus?P>0.05?,others difference were statistically significant?P<0.05?.The MI/Cr ratios of the bilateral hippocampus in the aMCI group was higher than those in the control group and the difference was statistically significant?P<0.05?.ConclusionsThe results of 3D-PCASL and MB-DWI for the diagnosis of changes of hippocampus perfusion of patients with amnestic mild cognitive impairment are consistent,which can be used for evaluating changes of brain perfusion in amnestic mild cognitive impairment and are helpful for clinical diagnosis and treatment.The decline of NAA/Cr,Cho/Cr and MI/Cr ratio in bilateral hippocampus could possibly be the sensitive biological indicator of diagnosing amnestic mild cognitive impairment,if these ratios could be sensitive biological indicator of worsened cognitive function in MCI patients need further study with enlarged samples and prolonged follow up.