急性脑梗死后血管性认知障碍的磁共振波谱研究

目的应用质子磁共振波谱(1 H-MRS)技术,探讨急性脑梗死后血管性认知障碍(VCI)患者的颅内物质代谢变化与认知损害的关系。方法对86例脑梗死患者(脑梗死组)及21名健康对照者(对照组)进行简易精神状态检查量表(MMSE)和蒙特利尔认知评分量表(MoCA)评分,并计算其视空间及执行功能评分。根据认知评分结果,将脑梗死组分为脑梗死后认知功能正常组(NCI)、脑梗死后VCI非痴呆组(VCIND)、脑梗死后痴呆组。对脑梗死组及健康对照进行1 H-MRS检查,测定右额叶、左颞叶、左丘脑及顶枕叶交界处N-乙酰天冬氨酸(NAA)/肌酸(Cr)、肌醇(mI)/Cr及胆碱复合物(Cho)/Cr比值,并分析脑梗死组物质代谢比值与认知评分(MoCA评分、视空间及执行功能)间的相关性。结果 (1)与对照组(左颞叶及左丘脑NAA/Cr 1.53±0.08、1.52±0.10)相比,VCIND组左颞叶及左丘脑NAA/Cr(1.46±0.07、1.47±0.07)降低(P=0.001、P=0.006);与VCIND组右额叶1.46±0.10比较,梗死后痴呆组右额叶、左颞叶及左丘脑NAA/Cr(1.38±0.14、1.39±0.06、1.42±0.09)降低(分别P<0.001、P<0.001、P=0.003)。对照组及NCI组间的各区域物质代谢比值无统计学差异(均P>0.05)。(2)所有脑梗死患者中,除右额叶Cho/Cr外,余各感兴趣区物质代谢比值与MoCA评分间均相关,其中以左颞叶、左丘脑NAA/Cr值与MoCA评分的相关性为著(分别r=0.566,P<0.001;r=0.485,P<0.001);除右额叶、丘脑及顶枕叶交界处Cho/Cr外,余各物质代谢比值与视空间及执行功能评分间相关,其中亦以左颞叶及左丘脑NAA/Cr值的相关性为著(分别NAA/Cr为r=0.591,P<0.001;r=0.491,P<0.001)。结论左丘脑及左颞叶代谢异常可能为VCI患者认知损害的早期关键环节之一,随着VCI病变进展可能整个皮质及皮质下环路区域都将出现代谢异常。

1H-MRS findings in patients with VCI after cerebral infarction(CI)

Objective To identify the metabolic changes of brain in patients with vascular cognitive impairment(VCI)after cerebral infarction(CI) by proton magnetic resonance spectroscopy(1H-MRS). Methods 86 patients with CI and 21 controls were enrolled.They were tested by mini-mental state examination(MMSE) and Montreal cognitive assessment(MoCA).The score of visuospatial and executing skills was calculated.According to the scores of cognitive ability,all subjects were divided into 4 groups: no cognitive impairment(NCI) group after CI,cognitive impairment,but not dementia(VCIND) group after CI,dementia group after CI,and control group.All groups received MRS examination.The ratios of N-acetyl aspartate/creatine(NAA/Cr),choline/creatine(Cho/Cr),and myo-inositol/creatine(mI/Cr) in the right frontal lobe,the left temporal lobe,the left thalamus and mid-line-parietal-occipital region were calculated.Moreover,the correlations between scores of MoCA as well as its sub-item(visuospatial and executing skills) and the ratios of NAA/Cr,Cho/Cr,mI/Cr were analyzed in all CI patients. Results Compared with control group(1.53±0.08,1.52±0.10),the ratio of NAA/Cr in the left temporal lobe and the left thalamus(1.46±0.07,1.47±0.07) decreased in VCIND group(P=0.001,P=0.006);compared with VCIND group(1.46±0.10,1.46±0.07,1.47±0.07),the ratio of NAA/Cr in the right frontal lobe,the left temporal lobe,and the left thalamus(1.38±0.14,1.39±0.06,1.42±0.09)decreased remarkably in the dementia group(P<0.001,P<0.001,P=0.003);the ratios of NAA/Cr,Cho/Cr,and mI/Cr were no statistical difference between NCI group and control group;The ratios of NAA/Cr and mI/Cr in all regions were all correlated with cognitive ability,and moreover,the ratio of NAA/Cr in the left temporal lobe and the left thalamus were significantly correlated with the score of MoCA(r=0.566,P<0.001;r=0.485,P<0.001) and the score of visuospatial and executing skills(r=0.591,P<0.001;r=0.491,P<0.001),and the ratio of Cho/Cr in the temporal lobe was correlated with the score of visuospatial and executing skills(r=-0.231,P=0.037). Conclusions Metabolic abnormalities in the left thalamic and the left temporal neurons maybe an early and crucial part in the pathogenesis of VCI,and the whole frontal-subcortical circuits may be disrupted with the development of cognitive impairment.