轻度认知障碍和阿尔茨海默病的边缘系统氢质子磁共振波谱特点

~1H-MRS changes in limbic system in mild cognitive impairment and Alzheimer disease

目的探讨海马和扣带回后部氢质子磁共振波谱(’H-MRS)改变在轻度认知障碍(MCI)和阿尔茨海默病(AD)早期诊断中的作用。方法应用’H-MRS技术检测15名健康老年人、15例MCI患者及15例AD患者脑内边缘系统的代谢物水平,对检测的N-乙酰天门冬氨酸(NAA)、胆碱复合物(Cho)、肌酸复合物(Cr)和肌醇(mI)波谱数据进行比较分析。结果 AD组与健康对照组和MCI组相比,海马部位的mI/Cr均升高(均P<0.05),NAA/mI降低(均P<0.05);随病情进展,扣带回后部的mI/Cr呈递增趋势(P<0.05),NAA/mI呈递减趋势(P<0.05);AD组和MCI组扣带回后部的NAA/mI与健康对照组的差别程度大于海马部位(P=0.001,P=0.019)。结论扣带回后部的mI/Cr和NAA/mI有助于鉴别健康老人和AD患者;海马部位的NAA/mI有助于鉴别痴呆和非痴呆;MRS在诊断AD和MCI方面有一定辅助作用。

Objective To investigate the role of ^1H-MRS changes in the posterior cingulated gyrus and the hippoeampus in the diagnosis of mild cognitive impairment （MCI） and early Alzheimer disease （AD）. Methods ^1H-MRS was performed in 15 MCI patients, 15 AD patients and 15 age-matched normal healthy controls, with Siemens Trio TIM 3.0T MRI scanner using single voxel PRESS at the posterior cingulated gyrus and multiple voxel PRESS at bilateral hippoeampus. The metabolic concentrations of N-acetylaspartate （NAA）, choline （Cho）, creatine （Cr）, myoinositol （mI） and their ratios to Cr or mI were analyzed among normal, MCt and AD groups. Results In the hippocampus the mI/Cr was significantly enhanced and the NAA/mI was significantly deeresed in AD compared with those in normal （P〈0.05） and MCI （P〈0.05）. With the disease getting worsen, in posterior cingulated gyrus the mI/Cr was increasing （P〈0.05）, and the NAA/mI decreasing （P〈0. 05）. We found the changes of NAA/mI at posterior cingulated gyrus between AD and control and MCI and control were bigger than those in hippocampus （P = 0. 001, P = 0. 019）. Conclusions The NAA/mI and mI/Cr alterations in the posterior cingulated gyrus may be useful in differentiating normal elders and AD patients; NAA/mI changes in the hippoeampus may be useful in differentiating the demented （AD） and non-demented （normal and MCI） conditions. MRS in the posterior cingulated gyrus and the hippocampus may be helpful in the diagnosis of AD and MCI.