探讨健康成人视辐射的磁共振弥散张量成像与年龄的相关性

Assessment on age-related changes in optic radiation with diffusion tensor imaging in healthy adults

目的定量分析正常成人视辐射的DTI中各参数与年龄的相关性。方法选取健康志愿者50名行DTI扫描,年龄20～75岁,分为5个连续的年龄组。将图像载入DTI studio 2.4中,分别在双侧视辐射勾画ROI,得到FA、平均弥散率(MD)及神经纤维根数(NOF),分析双侧间的差异性、不同组间差异性及与年龄间的相关性,并用SPM 2软件分析不同组间视辐射FA、MD值变化趋势,验证所得结果。结果双侧视辐射FA、MD及NOF之间差异均无统计学意义(P均>0.05);双侧FA、MD及NOF各组间差异有统计学意义(P均<0.05);双侧FA与年龄呈负相关(右侧:r=-0.856,左侧:r=-0.864,P均<0.05),双侧MD与年龄无相关性(P均>0.05),双侧NOF与年龄呈负相关(右侧:r=-0.498,左侧:r=-0.674,P<0.05);SPM2仅显示出视辐射区持续扩大的FA减低,与勾画ROI法所得结果相符。结论成人双侧视辐射随年龄增长出现FA减低和神经纤维数目减少,而MD的变化与年龄无相关性。

Objective To analyze the correlation between age and quantified parameters of diffusion tensor imaging（DTI）.Methods Fifty healthy volunteers were divided into 5 groups from 20 to 75 years old.All subjects underwent DTI scanning,and the parameters including FA,mean diffusivity（MD） and the number of fibers（NOF） were quantified by methods of ROI in DTI studio.Difference or correlation between the parameters and the age were analyzed.The SPM2 software was used to generate FA and MD changing maps,which could prove the accuracy through comparing to the results by ROI.Results FA,MD and NOF had no significant difference between bi-sides optic radiation（all P0.05）.FA,MD and NOF had significant difference among 5 groups（all P0.05）.Bi-sides FA and NOF values had negative correlation with age（FA,right：r=-0.856,left：r=-0.864;NOF,right：r=-0.498,left：r=-0.674,all P0.05）.No correlation between MD values and age was found（both P0.05）.The analysis results by SPM2 were in accordance with that by the method of ROI.Conclusion The FA and NOF values are reducing with aging in optic radiation.No evidence proves the correlation between MD and age.