定量研究人脑投射纤维扩散张量成像与年龄的关系

目的定量研究健康人脑投射纤维扩散张量成像(DTI)的分数各向异性(FA)、平均扩散系数(MD)图及其与年龄的关系。方法健康志愿者58例,年龄22～76岁,按年龄分为年轻组(≤40岁)30例,中老年组(>40岁)28例,采集人脑常规MRI及DTI图像,经后处理得到DTI的FA及MD参数图,使用FA图设置人脑投射纤维不同层面的6对兴趣区,定量分析FA、MD图的对称性及其与年龄的关系。结果年轻组桥脑投射纤维FA值左侧>右侧(P=0.011),中老年组所有层面投射纤维的FA、MD值左右侧对称。桥脑投射纤维FA值与年龄呈负相关关系(r=-0.57,P=0.000);MD值在半卵圆中心与年龄呈正相关关系(r=0.338,P=0.009)。结论健康人脑投射纤维DTI参数的左右对称性与年龄有关,投射纤维在桥脑的FA值与年龄呈负相关关系,在半卵圆中心的MD值与年龄呈正相关关系。

Quantitative study on the correlation between diffusion tensor imaging in human brain projection fibers and age

Objective To quantitatively analyze the diffusion tensor imaging fractional anisotropy（DTI FA）,mean diffusivity（MD） parameter maps in human brain projection fibers,and to investigate the correlation between these parameters and age.Methods The 58 healthy volunteers（age range：22~76yr） were divided into two group according to their age,30 subjects in young group（≤40yr） and 28 subjects in midddle-old age group（40yr）.The MRI and DTI were performed for all the subjects,then the parameter maps of DTI FA and MD were got after treated.The six-pair of ROIs of the projection fibers were determined according to FA maps.FA and MD values were measured in the two groups.The symmetry of FA,MD maps was quantitatively analyzed,and the correlation between the symmetry and age was analyzed.Results In the young group,the value of FA in left side was greater than that of right side（P0.05）,however,in the middle-old age group,the values of FA and MD of projection fibers at all horizons appeared the symmetry between left side and right side.The FA value of pons projection fibers was negatively related with age（r=-0.57,P0.01）.However MD value in centrum semiovale was positively correlated with age（r=0.338,P0.01）.Conclusion The left-right symmetry of the projection fibers of DTI parameters in brains of healthy subjects is related to age.In pons projection fiber,the FA value is negatively correlated with age,however,the MD value in centrum semiovale is positively correlated with age.