健康儿童颈髓磁共振扩散张量成像

目的 应用扩散张量成像技术研究儿童颈髓发育规律。方法 使用单次激发自旋回波平面回波序列对90例健康儿童行颈髓扩散张量成像。在颈髓节段分别测量其表观扩散系数值（ADC）、各向异性分数值（FA）、纤维束平均长度（Ltract）以及纤维束体积（Vtract）。结果 各组的ADC值、FA值、Ltract及Vtract分别如下：0.9747±0.2777、0.8493±0.2236、0.8210±0.1432、0.9198±0.1444、0.9048±0.1676；0.4117±0.0391、0.4712±0.0199、0.4944±0.0439、0.5608±0.0443、0.6169±0.0551；25.61±8.63、24.66±7.14、27.03±7.23、34.93±10.99、37.63±10.22；3.07±1.49、3.00±1.52、3.81±1.33、5.41±2.35、6.64±2.84。各年龄组的FA值、Ltract和Vtract不完全相同（P<0.001），而ADC值各年龄组的均值差异无统计学意义（F=1.758, P=0.145）。在组间的两两比较中：1、2组间FA值差异具有统计学意义；3、4组间FA值、Ltract和Vtract差异均具有统计学意义；4、5组间FA值差异具有统计学意义。FA值、Ltract和Vtract与年龄呈正相关。
结论 儿童颈髓发育具有阶段性，且具有阶段性特征；磁共振扩散张量技术可用于观测儿童颈髓并评价其发育。

Magnetic resonance diffusion tensor imaging of cervical cord in healthy children

Objective To investigate the development of the cervical cord in children by using diffusion tensor imaging.Methods Ninety healthy children were undergone with diffusion tensor imaging of the cervical cord by using single-shot spin-echo echo planar image sequence. The values of apparent diffusion coefficients (ADC), fractional anisotropy (FA), average length(Ltract) and volume of tracts(Vtract) were measured in the cervical regions. Results The measurements of each group were as follow: ADC value: 0.9747±0.2777,0.8493±0.2236,0.8210±0.1432,0.9198±0.1444,0.9048±0.1676；FA value:0.4117±0.0391,0.4712±0.0199,0.4944±0.0439,0.5608±0.0443,0.6169±0.0551； Ltract:25.61±8.63,24.66±7.14,27.03±7.23,34.93±10.99,37.63±10.22；Vtract:3.07±1.49,3.00±1.52,3.81±1.33,5.41±2.35,6.64±2.84. FA value， Ltract and Vtract showed significance in different age groups, while ADC value was found no difference (P<0.001). Post Hoc test revealed that FA value was significantly different between age group I and Ⅱ. FA value, Ltractand Vtract presented significantly different between group Ⅲ and Ⅳ. FA value difference was also found between group Ⅳ and V. FA value, Ltract and Vtract were all positively corelative with age (F=1.758,P=0.145). Conclusion Development of the cervical cord shows periodicity with periodic features. Diffusion Tensor Imaging can be used as a tool to observe and evaluate development of the cervical cord in children.