正常成人和阿尔茨海默病的扣带回后部质子磁共振频谱研究

目的 评价质子磁共振频谱在阿尔茨海默病（AD）诊断中的价值。方法 将研究对象分为三组，即临床拟诊的AD组（18例），血管性痴呆组（VD组，25例），正常对照组（60例）。正常对照组再分为两组（50～60岁组和大于60岁组）。所有病人均排除糖尿病及其他高渗性疾病。对各组进行头颅常规MRI扫描及扣带回后部的单体素PRESS MRS检查，用SPSS软件包进行数据处理，正常对照组间采用团体t检验，正常组与AD组、VD组对比用方差分析法及q检验。结果 正常对照组两年龄段NAA／Cr、Cho／Cr、及mI／Cr值均无显著性差异（P〉0．05）；AD组分别与VD组、正常对照组比较，NAA／Cr、Cho／Cr三组间比较差异无统计学意义（P〉0．05），而mI／Cr值在三组之间比较差异有统计学意义（P〈0．05）。结论 50岁以上正常人群mI／Cr值不会随年龄增长而上升，AD患者扣带回后部mI／Cr值明显升高，若以大于0．76为标准，则本组AD诊断的阳性预测值接近100％，阴性预测值94．5％。

Proton MR spectroscopy study of posterior portion cingulate gyrus both in patients with Alzheimer''s disease and normal adults

Objective To evaluate the role of proton magnetic resonance spect roscopy in patient s with Alzheimer's disease(AD) . Methods All subject s were divided into three groups : AD group (18 cases) , vascular dementia (VD) group (25 ca-ses) , and normal cont rol group (60 cases) . According to their ages, the cont rol group was classified into two groups : thefirst group with ages f rom 50 to 60 years , the second group with ages > 60 years. We used the same protocols : conventionalMRI and MRS. Spect roscopy was acquired by single voxel PRESS , TR 1500 ms , TE 30 ms , volume 8 cm. Saggital view was selected as scout image. The region of interest was located in the posterior portion of cingulate gyrus. We used SPSS sof tware package to process the data. We used grouped t test in testing the difference between the two normal groups and ANOVA for AD , VD and cont rol groups. The ratios of NAA/ Cr , Cho/ Cr , mI/ Cr were analyzed. Results There was no significant differences between the two cont rol goup s (P>0.05) . The ratios of NAA/Cr, Cho/Cr , mI/ Cr among AD , VD, and cont rol group s were compared , the result s showed no significant differences between the ratios of NAA/ Cr,Cho/Cr(P> 0.05) . However , the ratio of mI/ Cr had significant difference (P<0.05).Conclusion The ratio of mI/ Cr did not in-crease with aging in > 50 years normal cont rols. Obvious increasing the ratio of mI/ Cr was found in AD group. If the value of mI/ Cr measured in the posterior portion cingulated gyrus large than 0.76 was used as criteria of AD , the positive predic-tive value of AD was 100 % and negative predictive value was 94. 3 % in this study. But the most important thing was to rule out diabetes and other diseases which also had high mI/ Cr.