轻度阿尔茨海默病和血管性痴呆患者认知损害及与扣带回后部和海马氢质子磁共振波谱的相关性研究

Proton magnetic resonance spectroscopy study of posterior cingulate and hippocampus in patients with mild vascular dementia and Alzheimer disease

目的分析轻度阿尔茨海默病(AD)和血管性痴呆(VD)患者的认知损害程度及与氢质子磁共振波谱(1H-MRS)的关系,探讨其对AD与VD的诊断和鉴别诊断的作用。方法 AD组28例、VD组30例、健康对照组22例,采用简易精神状态量表(MMSE)、蒙特利尔认知评估量表(Mo CA)进行认知功能评分;采用刺激回波序列进行检测,计算双侧海马和扣带回后部的N-乙酰天冬氨酸/肌酸(NAA/Cr)、肌醇/肌酸(MI/Cr)、胆碱/肌酸(Cho/Cr)、N-乙酰天冬氨酸/肌醇(NAA/MI)等的比值;比较各组间认知功能评分和各代谢物比值的差别,并进行相关分析。结果 (1)AD组和VD组的Mo CA总分、MMSE评分均低于对照组,差异有统计学意义(P<0.05);VD组汉密尔顿焦虑量表(HAMA)评分高于AD组和对照组(P<0.05);(2)AD组和VD组左侧海马、扣带回后部的NAA/Cr比值均低于对照组(P<0.05);AD组和VD组扣带回后部的Cho/Cr比值低于对照组;AD组和VD组左侧海马、扣带回后部的MI/Cr比值高于对照组(P<0.05);AD组和VD组左侧海马、扣带回后部的NAA/MI比值均低于对照组(P<0.05)。与VD组相比,AD组左侧海马、扣带回后部的NAA/Cr比值升高,差异有统计学意义(P<0.05),扣带回后部的Cho/Cr比值降低,差异有统计学意义(P<0.05),左侧海马、扣带回后部的MI/Cr比值升高,差异有统计学意义(P<0.05);(3)AD组和VD组的Mo CA总分、MMSE评分与左侧海马、扣带回后部的NAA/Cr存在正相关(P<0.05),AD组MMSE评分与扣带回后部的NAA/MI存在正相关(P<0.05),而VD组MMSE评分与扣带回后部的NAA/MI无相关性(P>0.05)。结论在认知损害程度方面轻度AD患者与VD患者具有相似性,且认知损害程度与左侧海马、扣带回后部的1H-MRS具有相关性,认知功能评分与1H-MRS结合可作为AD和VD早期诊断、鉴别诊断的重要工具。

Objective To investigate the significance of cognitive evaluation and proton magnetic resonance spectroscopy(1H-MRS) for the diagnosis and the differential diagnosis of mild Alzheimer disease(AD) and vascular dementia(VD), through analyzing the cognitive impairment characteristics and the correlation with 1H-MRS. Methods Cognitive function score were assayed according to mini-mental state examination(MMSE) and Montreal cognitive assessment(Mo CA) in 28 cases of patients with AD, 30 cases of VD patients and 25 healthy controls. A stimulated echo acquisition mode was used to detect and calculate the ratios of N-acetyl aspartate/creatine(NAA/Cr), myoinositol/creatine(MI/Cr), choline/creatine(Cho/Cr), and N-acetyl aspartate/myoinositol(NAA/MI) in the bilateral hippocampus and the posterior cingulate. Then the differences of memory function score and ratios were compared, and correlation analysis between them was performed. Results Scores of the AD and VD group on the Mo CA scores and MMSE score were all lower than those of control group(P<0.05). Scores of the VD group on the HAMA scores were lower than those of AD and control group(P<0.05). The NAA/Cr ratios of the left bilateral hippocampus and posterior cingulate in the AD group and VD group were all lower than those in the control group. There were significant differences(P<0.05). The Cho/Cr ratios of the posterior cingulate in the AD group and VD group were all lower than those in the control group, there were significant differences(P<0.05). The MI/Cr ratios of the left bilateral hippocampus and posterior cingulate in the AD group and VD group were all higher than those in the control group(P<0.05). The NAA/MI ratios of the left bilateral hippocampus and posterior cingulate in the AD group and VD group were all lower than those in the control group. Patients with VD showed significant reduction of NAA/Cr and MI/Cr ratios in left bilateral hippocampus and posterior cingulate and significant increment of Cho/Cr ratios in the posterior cingulate compared to AD group(P<0.05). In AD and VD group, Mo CA scores and MMSE score were all positively correlated with NAA/Cr ratios in the left bilateral hippocampus and posterior cingulate(P<0.05). In AD group, MMSE score were all positively correlated with NAA/MI ratios in the posterior cingulate(P<0.05). But in AD group, MMSE score had no correlation with NAA/MI ratios in the posterior cingulate(P>0.05). Conclusions AD has similar cognitive evaluation with VD, and cognitive evaluation correlated with 1H-MRS in the left bilateral hippocampus and posterior cingulate. The combination of cognitive function score and 1H-MRS could be effective on early diagnosis and differential diagnosis of AD and VD.