A study on posterior cingulate gyrus glutamate levels in mild cognitive impairment patients using proton magnetic resonance spectroscopy with multi-voxel.

Abstract

Objective To explore the diagnosis value of quantitative analysis of glutamate(Glu) with mild cognitive impairment (MCI) by proton magnetic resonance spectroscopy (1H-MRS). Methods According to the clinical diagnosis standard for cognitive function, the study group included 20 patients with mild cognitive impairment (MCI group, 9 males and 11 females) and 20 patients with Alzheimer′s disease (AD group, 10 males and 10 females), and the control group used 20 healthy volunteers (NC group, 9 males and 11 females). All of the patients and volunteers were scanned by multi voxel 1H-MRS using rapid acquisition with relaxation enhancement (RARE) and point-resolved spectroscopy (PRESS) pulse sequence. The levels of the Glu and Cr were measured in the posterior cingulate gyrus, hippocampus and the frontal gyms cortex automatically by the NUTS-NMR Utility Transform Software. The ratios of Glu/Cr were calculated and compared among the groups. Comparisons of the cognitive function and the 1H-MRS indexes among MCI, AD and NC group were conducted by single factor analysis of variance (one-way ANOVA), between two groups significantly compared with minimal difference method (LSD). Results Gender, age, and the fixed number of year of the education comparison between each group had no statistical difference (P>0.05). MMSE detection showed that cognitive function in the MCI group was lower than that in the NC group, and difference was statistically significant (t=0.427, P 0.05), but the Glu/Cr ratios of the hippocampus region in AD (0.32±0.03) and NC groups were significantly different (t=0.594, P<0.05). There were no significant changes in Glu/Cr ratios among AD, MCI and NC groups (0.41±0.03, 0.43±0.03 and 0.43±0.03). Conclusion In 1H-MRS test, Glu may be an effective biochemical index of the diagnosis of MCI. 1H-MRS quantitative analysis provides the important basis for the early diagnosis of MCI. Key words: Cognitive disorder; Alzheimer disease; Glutamic acid; Magnetic resonance Spectroscopy