磁共振波谱及扩散张量成像联合评价轻中度Alzheimer病白质损害

目的 应用1H-磁共振波谱(~1H-MRS)及扩散张量成像(DTI)2种磁共振新技术联合评价轻中度Alzheimer病(AD)的自质损害.方法 AD患者20例,健康对照组20例,均进行临床检查,神经心理评估和GE Signa 3.0T超导磁共振检查,采用PRESS序列,对双侧侧脑室顶旁白质感兴趣区N-乙酰天门冬氨酸(NAA)、肌醇(mI)、含胆碱复合物(Cho)及肌酸和磷酸肌酸(Cr)浓度进行采集,并计算NAA/Cr、mI/Cr及Cho/Cr比值.同时进行常规MRI和DTI扫描,对双侧侧脑室顶旁相同部位白质感兴趣区的部分各向异性分数(FA)和平均扩散率(MD)的平均值进行测量,并行统计学处理.结果 AD组NAA/Cr比值与对照组比较差异无显著性(P＞0.05),mI/Cr及Cho/Cr比值较对照组明显升高(P＜0.05).AD组FA及MD值分别为0.470±0.082和0.771±0.099,对照组FA及MD值分别为0.539±0.068和0.691±0.064,AD组FA值较对照组明显降低(P＜0.05),MD值较对照组明显升高(P＜0.05).偏相关分析显示,控制年龄后,mI/Cr比值与FA值呈负相关关系(P＜0.05),与MD值无相关关系(P＞0.05).结论 AD患者侧脑室顶旁白质区mI及Cho浓度增加,DTI检测出相同部位FA值降低,MD值升高,提示AD患者不仅存在着灰质病变,白质亦受累;~1H-MRS与DTI结合能更好地检测出AD患者的自质损害.

Evaluation of white matter lesions in patients with mild and moderate Alzheimer's disease using proton magnetic resonance spectroscopy and diffusion tensor imaging

Objective To investigate the pattern of the cerebral white matter lesions in patients with mild and moderate Alzheimer's disease(AD)and healthy controls using proton magnetic resonance spectroscopy(~1H-MRS)and diffusion tensor imaging(DTI).Methods Twenty AD patients and Twenty healthy controls were recrnited.All subjects underwent clinical examination,neuropsychological assessment.The quantitative analysis of N-acetylaspartate(NAA),myoinositol(mI),Chotine(Cho)and Creatine(Cr)resonance signals in region of interests(ROIs)located in the paraventricular white matter region bilaterally were measured.Ratios of NAA/Cr,mI/Cr and Cho/Cr were calculated in two groups.In addition,conventional MRI and DTI scanning were received,fractional anisotropy(FA)and mean diffusivity(MD)values of white matter in the same regions were measured respectively.Results No significant difference between two groups were observed in NAA/Cr ratio(P＞0.05).A significantly increased mI/Cr and Cho/Cr were found in AD patients than in controls(P＜0.05).FA and MD values in AD patients were 0.470±0.082 and 0.771±0.099,and in controls were 0.539±0.068 and 0.691±0.064,respectively.FA value decreased significantly in AD patients(P＜0.05),M D value increased significantly in AD patients(P＜0.05).After controlling for age-related,partial correlation analysis revealed a negtive correlation between mI/Cr and FA value in the patients with AD(P＜0.05).No correlation between mI/Cr and MD was found(P＞0.05).Conclusion The results suggest that not only the gray matter is injured,but also the white matter is abnormal in AD patients.Combining ~1H-MRS with DTI alterations could provide the valuable informations about white matter lesions in AD patients.