The Study Of 1~H-magnetic Resonance Spectroscopy And The Association Between Spectral And Cognitive Performance In Patients With Mild Cognitive Impairment

Purpose: We compared the difference of 1H-magnetic resonance spectroscopy (1H-MRS) performance in left hippocampus and other regions between mild cognitive impairment (MCI) and normal aging, in order to investigate the value of 1H-MRS in the diagnosis of MCI and the relationship between metabolite ratios and cognitive performance in patients with MCI.Methods: A battery of neuropsychological tests including Mini Mental state examination (MMSE), Cambridge cognitive examination of Chinese Version of elderly (CAMCOG-C), Geriatric Depression Scale (GDS) were performed in 12 cases of MCI and 14 cases of normal control, There were no significant difference (P> 0.05) between the two groups in gender, age, educational level, routine MRI were taken on each cases by GE Signa 3.0T superconducting MRI in order to eliminate diseases of the brain, followed by 1H-MRS scan, We selected the left frontal lobe, left basal ganglia and left hippocampus as regions of interest (ROI). Results were given by the system automatically which Cr as a reference to the various metabolites signal intensity ratios, such as NAA / Cr, Cho / Cr, mI / Cr and then calculate the NAA / MI. We used statistical software to compare the difference of metabolite ratios of each ROI between control and MCI group, Correlation coefficients between metabolite ratios and cognitive scores were calculated in MCI group.Results:Compared with the control group, NAA/Cr in left frontal lobe, NAA/Cr and NAA/MI in left hippocampus of the MCI reduced significantly (left frontal lobe, 1.39±0.06 vs.1.47±0.12, t=-2.239,P=0.035; left hippocampus, 1.28±0.07 vs.1.39±0.10, t=-3.009, P=0.006; 1.58±0.15 vs. 1.84±0.19, t=-3.774,P=0.001 respectively), MI/Cr in left hippocampus of the MCI increased significantly(0.82±0.06 vs. 0.76±0.05, t=2.662, P=0.014).However, there were no significant differences of metabolite ratios in left basal ganglia between two groups(P>0.05). NAA/Cr and NAA/MI of left hippocampus of the MCI had a significantly positive correlation with CAMCOG-C scores(r=0.568 and r=0.654 respectively, P<0.05) and part of its subitem.Conclusions: 1) Compared with the controls, NAA/Cr in left frontal lobe and left hippocampus of the MCI were both reduced, MI/Cr increased in left hippocampus, however, there were no significant differences of metabolite ratios in left basal ganglia between two groups. 2) NAA/Cr and NAA/MI of MCI in left hippocampus related to CAMCOG-C score and part of its subitem. Reduced NAA of left hippocampus, especially reduced NAA/MI might relate to cognitive impairment of MCI.3) Cognitive evaluation and MRS might discriminate MCI and normal subjects.