年龄相关性视辐射功能减退的磁共振DTI各向异性研究

To Study the Age-ralated Functional Degradation in Optic Radiation by Analysing Fractional Anisotropy in Diffusion Tensor Imaging

目的通过定量分析磁共振弥散张量成像(DTI)中部分各向异性(FA)值的减低来评价成人视辐射随年龄增长的功能减退区域。方法选取18～75岁健康志愿者40例,按年龄分为5组,第1组18～35岁8例作为对照组,第2～5组分别为36～45岁,46～55岁,56～65岁和66～75岁,每组人数均为8例,分别行DTI检查后,对得到的FA图通过SPM2软件进行T检验分析,得到各组的FA值减低区域分布图。结果与第1组比较,第2组出现右侧视辐射FA减低区,第3组出现双侧视辐射FA减低区,范围较第2组略扩大,第4、5组与第1组比较双侧视辐射均出现FA值减低区,范围明显扩大。各组FA值减低的程度随年龄增长逐步加深。结论成人视辐射FA值随年龄的增长出现了区域性减低,并逐渐加重,磁共振弥散张量成像作为无创性检查,对评价视辐射的正常功能退化有重要的价值。

Objective To evaluate the age-related degradation in opitic radiation by analyzing the decrease of fractional anisotropy（FA） in diffusion tensor imaging. Methods Forty healthy volunteers were divided into five groups. Each group include eight objects. The first group was from 18 to 35 years old and was regarded as the control group. The other four groups were from 36 to 75 years old with the interval between two adjacent groups being ten years. Each volunteer had been performed a DTI scanning and the FA maps were analyzed by SPM software to generate FA decreasing maps. Results In comparison between group 2 （age 36-45） and control group, the decreasing FA ragion was found in right opitic radiation. In comparison between group 3 and control group, the decreasing regions which were slightly enlarged than group 2 were found in bilateral optic radiation. In comparison between group 4, group 5 and control group, the range of decreasing region were apparently enlarged and the degree were deeper than group 2 and group 3. The range and degree of FA reduction appeared positive correlation with the rising age. Conclusion There are significant age-related degradation regions in opitic radiation which are keeping aggravating with the age rising. DTI as a noninvasive examination has an important value in studying the age-ralated degradation of human brain.