Preliminary MRS study of critical values of relevant brain metabolites in elderly Chinese patients with post-stroke cognitive impairment

Objective: Proton magnetic resonance spectroscopy (H-1-MRS) was applied in this study to detect metabolite changes in the brain of post-stroke cognitive impairment (PSCI) and normal volunteers. The levels of N-acetylaspartate (NAA) and creatinine (Cr) and in the frontal lobe, hippocampus and cingulate gyrus were measured to distinguish patients with post-stroke cognitive impairment (PSCI) and normal control group (NC). The relationship between them and cognitive function was explored and a critical value of the metabolite ratio was predicted. This study may serve as a reference for the diagnosis of cognitive dysfunction after stroke. Methods: A total of 46 patients with PSCI (PSCI group, all patients are unilateral cerebral infarction or intracerebral haemorrhage) were screened by the Mini-Mental Status Examination (MMSE), and 35 healthy volunteers were selected as normal control group (NC group). The general information of gender, age, and education level was matched between the two groups. Two groups of subjects were examined using MRS and evaluated for cognitive function using the MMSE test and the Montreal Cognitive Assessment Scale (MoCA). The correlation between MRS and neurobehavioral scale (MMSE test and MoCA scale) was analysed, and the possible demarcation points of the brain metabolism of PSCI were evaluated. Result: The MMSE and MoCA scores of patients with PSCI were lower significantly when compared with those of the NC group (P < 0.05). The NAA/Cr values of the bilateral hippocampus, bilateral frontal lobe and bilateral anterior and posterior cingulate gyrus in the PSCI group were lower than those in the NC group (P < 0.05). The NAA/Cr cut-off value for the right frontal lobe was 1.533, and the NAA/Cr sensitivity, specificity and Youden index for the right frontal lobe were 0.943, 0.935, and 0.878. Conclusion: NAA/Cr values in the MRS bilateral frontal, bilateral hippocampus and bilateral anterior and posterior cingulate gyrus were reduced in the cognitively impaired post-stroke patients compared to the normal control group. MRS was also found to be correlated with the score of neurobehavioral scale (MMSE test and MoCA scale) and the combination of the two could evaluate cognitive dysfunction more comprehensively and objectively. NAA/Cr value of the right frontal lobe < 1.533 indicated that PSCI may occur. In accordance with this cut-off point, PSCI could be detected as early as possible and timely intervention could be carried out.