不同认知水平的广泛性脑萎缩患者磁共振波谱分析

The analysis of the neural metabolites in patients with global brain atrophy and different cognitive function in hippocampus and frontal cortex

目的观察不同认知水平的广泛性脑萎缩患者脑内生化物质含量的差异。方法按照美国精神障碍诊断与统计手册第4版（DSM-Ⅳ）和认知功能障碍的诊断标准将33名广泛性脑萎缩患者分为阿尔茨海默病（AD）组14例、遗忘型轻度认知功能损害（aMCI）组9例和认知功能正常组10例。所有研究对象接受神经心理量表检测，然后采用1．5-TMR系统对左侧额叶皮质和左侧海马进行氢质子磁共振波谱（1H-MRS）检测分析。结果广泛性脑萎缩AD组的左侧海马和左侧额叶皮层的N-乙酰天门冬氨酸（NAA）／肌酸（Cr）值较认知正常组分别降低10．2％和5．3％，胆碱复合物（Cho）／Cr值分别升高17．5％和16．7％，肌醇（MI）／Cr值分别升高39．5％和19．2％。与aMCI组比较，广泛性脑萎缩AD组的左侧海马NAA／Cr值降低6．4％，左侧海马和左侧额叶皮层的Cho／Cr值分别升高9．3％和12．3％，左侧海马和左侧额叶皮层的MI／Cr值分别升高30％和17％，而左侧额叶皮层的NAA／Cr值在两者间差异无统计学意义。广泛性脑萎缩aMCI组的左侧海马NAA／Cr值比正常组降低4．1％、Cho／Cr值比认知正常组升高7．5％，但是左侧额叶皮层的生化改变在两组间差异均无统计学意义。结论不同认知水平的广泛性脑萎缩患者存在脑内神经生化物质的变化。左侧海马NAA／Cr值的降低、左侧海马和左侧额叶皮质Cho／Cr和MI／Cr值的升高有助于预测aMCI进展为AD；左侧海马NAA／Cr降低和Cho／Cr升高有助于鉴别广泛性脑萎缩伴aMCI患者与广泛性脑萎缩认知功能正常的患者。

Objective Global brain atrophy was reported as an important structural change in Alzheimer＇s disease （AD）, while it has been detected in the older person with normal cognitive function. Therefore, this study was aimed at investigating the difference of the neural metabolites in the left hippoeampus （HIP） and left frontal cortex （FC） among patients who showed global brain atrophy but with different cognitive function. Methods The 33 patients with global brain atrophy confirmed by MRI scan, underwent a comprehensively clinical and neuropsyehological assessment including mini-mental state examination （MMSE）, activities of daily living seale （ADL） and clock drawing test（CDT）. According to the diagnostic and statistical manual of mental disorders, fourth edition（DSM-Ⅳ ） and Mayo clinic rochester（MCR）, 14 patients were diagnosed as AD, 9 patients as amnestic mild cognitive impairment（aMCI）, and 10 patients as normal cognition. Every person was taken a cerebral proton magnetic resonance spectroscopy（1H -MRS） scan to measure the levels of nacetylaspartate（NAA）, choline（Cho）, myo inositol（MI） and Creatine（Cr） in the left HIP and the left FC. Results While compared with the group with normal cognition, the ratio of NAA/Cr in the AD group reduced 10.2%in the left HIP and 5.3% in the left FC, and the ratio of Cho/Cr increased 17.5% in the left HIP and 16.7%in the left FC, and the ratio of MI/Cr increased 39.5% in the left HIP and 19.2% in the left FC. The ratio of NAA/Cr of the left HIP in the AD group was lower than that in the aMCI group at the decrease rate of 6.4%, while the ratio of NAA/Cr of the left FC was not significantly different between the two groups. The AD group had higher ratios of Cho/Cr at the increase rate of 9.3% in the HIP and 12.3% in the FC, and higher MI/Cr ratios at the increase rate of 30%in the HIP and 17% in the FC than in the aMCI group. The aMCI group showed significantly lower ratio of NAA/Cr at the decrease rate of 4.1 %and higher ratio of Cho/Cr at the increase rate of 7.50% in the left HIP than in the normal cognition group. Conclusions Among patients with global brain atrophy, the decrement of ratio of NAA/Cr in the left HIP and the increment of the ratio of Cho/Cr and MI/Cr are predictive of the progress from aMCI to AD. Moreover, the decrement of ratio of NAA/Cr in the left HIP and the increment of the ratio of Cho/Cr are helpful to distinguish the aMCI and the persons with normal cognition.