右利手正常年轻人脑投射纤维DTI参数图研究

目的 定量分析右利手年轻人脑投射纤维在扩散张量成像（DTI）参数图上的表现，探讨参数图的意义和相互关系。方法应用GE3T全身超导MRI仪，对30名右利手健康青年志愿者（男16名，女14名，平均年龄28．2岁）行常规颅脑MRI及DTI，重建DTI的部分各向异性FA、平均扩散系数MD和T2-weighedtrace三种参数图，观察投射纤维6个部位在参数图上的表现特征，测定三种参数值，定量分析投射纤维侧别、性别及部位的差别。结果①在投射纤维的6个部位，三种参数值皆无性别差异：②桥脑的投射纤维FA值左侧大于右侧（P=0.0111，桥脑、大脑脚、内囊前肢和半卵圆中心T2．weightedtrace值左侧大于右侧（P=0．000-0．017），MD在所有部位双侧差别无统计学意义；③6个部位平均FA值为大脑脚〉内囊后肢〉内囊膝部〉内囊前肢、桥脑〉半卵圆中心；④投射纤维T2．weighedtrace与FA、MD之间有负相关关系（r=0．169，P=0．024；r=0．149，P=0．0471。结论FA图对投射纤维显示最清楚，FA和MD反映水分子扩散的不同方面，T2-weighedtrace图应结合FA、MD图以及常规MRI进行综合分析。

Diffusion tensor imaging parameter maps of projection fibers from the brain in right-handed healthy young volunteers

Objective： To quantitatively analyze the diffusion tensor imaging parameter maps of the right-handed young human projection fibers, reveal the significance and correlation of three diffusion parameters： fractional anisotropy （FA）, mean diffusivity （MD） and T2-weighted trace. Materials and Methods： Thirty right-handed healthy young volunteers （16 men, 14 women; mean age of 28.2 years） underwent diffusion tensor imaging and conventional MR imaging with a GE 3T MR system. The FA, MD and T2-weighed trace were determined at six-pair of parts of the projection fibers. The gender, lateral and regional differences of the parameters values were tested, the correlation between different parameters were analyzed. Results： （1） No significant differences were found in FA, MD and T2-weighted trace due to gender. （2） The FA value of projection fibers in the left pons was superior to that in the right （P=0.011）, whereas the other five-pair regions of the fibers had no lateral differences. T2- weighted trace had lateral differences in the pons, peduncle, anterior limb of internal and centrum semiovale （P value was 0.000 to 0.017）. （3） The order of FA values was peduncle 〉 posterior limb of internal capsule 〉 genu of internal capsule 〉 anterior limb of internal capsule, pons 〉 centrum semiovale. （4） In the projection fibers, T2- weighted trace had negative correlation with FA and MD （r=-0.169, P=0.024; r=-0.149, P=0.047）. Conclusion： In showing the projection fibers, FA can give more details than the other two parameters. FA and MD are different parameters which reflect different aspect of the water molecule diffusion. T2-weighted trace map should be analyzed combining with FA, MD map and conventional MR imaging