To investigate the value of hydrogen proton magnetic resonance spectroscopy (¹H-MRS) in the differential diagnosis of amnestic mild cognitive impairment (aMCI) and non-amnestic mild cognitive impairment (naMCI).

Twenty-five cases of aMCI patients were enrolled, twenty-two cases with naMCI and twenty subjects were elderly with normal cognitive function (NC). They all received examination of ¹H-MRS.The regions of interest were examined, including the left hippocampus, the posterior cingulate gyrus, and the frontal lobes.The area under the peak was determined for N-acethyl aspartate (NAA), glutamate (Glu), inositol (mI) and creatine (Cr). The ratios of NAA/Cr, Glu/Cr and mI/Cr were compared in different brain regions among the three groups with SPSS 17.0.

Compared with the NC group, the ratio of NAA/Cr in the left hippocampus group was significantly lower than that in the aMCI and naMCI groups (1.09±0.11, 1.07±0.08, 1.20±0.21; t=0.247, 0.312; all P<0.05), and the ratio of NAA/Cr in the left posterior cingulate gyrus group was also significantly reduced with those in the aMCI and naMCI groups (1.02±0.09, 1.07±0.10, 1.22±0.18; t=0.442, 0.381; all P<0.05). However, no significant difference in the ratio of NAA/Cr in any brain region were observed between aMCI and naMCI groups (t=0.021, 0.036; P>0.05). The Glu/Cr ratio in the posterior cingulate gyrus of the aMCI group decreased significantly compared with that in the naMCI and NC groups (0.35±0.04, 0.43±0.02, 0.42±0.05; t=0.474, 0.405; all P<0.05). No significant difference in the Glu/Cr ratio was observed in other brain regions among the three groups (F=0.382, 0.363; all P>0.05). The mI/Cr ratio in the hippocampus was significantly bigger in the aMCI group than that in the naMCI and NC groups (0.66±0.07, 0.39±0.04, 0.41±0.04; t=0.293, 0.247; all P<0.05), and the mI/Cr ratio in the posterior cingulate gyrus was also significantly higher in the aMCI group than that in the naMCI and NC groups (0.62±0.05, 0.42±0.03, 0.44±0.04; t=0.255, 0.261; all P<0.05). The mI/Cr ratio in the frontal lobes of the naMCI group increased significantly compared with that in the aMCI and NC groups(0.58±0.04, 0.43±0.03, 0.41±0.03; t=0.174, 0.226; all P<0.05).

Regional differences of mI and Glu metabolism are found in brain tissues of patients with aMCI and naMCI.¹H-MRS is an effective method in the differential diagnosis of aMCI and naMCI.