T2 mapping及扩散张量成像在兔坐骨神经损伤中的应用

Application of T2 Mapping and Diffusion Tensor Imaging in the Injury of Sciatic Nerve in Rabbits

目的探讨T2 mapping及扩散张量成像(DTI)在评估兔坐骨神经损伤中的价值。材料与方法选择15只新西兰大白兔,建立右侧坐骨神经夹伤模型,左侧为对照侧。所有兔于损伤后3 d及1、2、3、4周行T2 mapping和DTI扫描。MRI扫描完毕后,于各时间点取1只白兔行病理检查。分析损伤侧坐骨神经各时间点的T2值和各向异性分数(FA)值,并运用改良Tarlov评分和趾展反射评分评价肢体功能恢复情况。结果兔坐骨神经夹伤远端3 d T2值上升,FA值下降,与对侧比较差异有统计学意义(P<0.05);1~4周T2值下降,FA值上升,与对侧比较差异有统计学意义(P<0.05);神经夹伤近端3 d T2值升高,FA值下降,1周恢复正常,与对侧比较差异无统计学意义(P>0.05)。坐骨神经损伤后T2值与功能评分呈负相关(r=-0.884,P<0.05);FA值与功能评分呈正相关(r=0.975,P<0.05)。结论 T2 mapping及DTI序列能够定量测定坐骨神经的损伤情况,可用于评估兔坐骨神经损伤的变化。

Purpose To explore the value of T2 mapping and diffusion tensor imaging （DTI） in assessing sciatic nerve injury in rabbits. Materials and Methods A group of 15 New Zealmld white rabbits was selected to establish right sciatic nerve crush models. The left side served as control group. All rabbits received T2 mapping and DTI on 3rd day, and at 1, 2, 3 mid 4 weeks after injury. After the MR scml, one white rabbit was examined at each time point for pathological examination. The T2 value mid fractional ainsotropy （FA） value of the injured sciatic nerve at each time point was analyzed. The improved TaJclov score mid toe reflex score were used to evaluate the recovery of limb function. Results The T2 value of distal-end injured sciatic nerves increased on 3rd day, mid the FA value decreased, with statistical differences compared with the normal side （P〈0.05）; at 1-4 weeks, the T2 value decreased, while FA value increased, with significmlt differences compared with the normal side （P〈0.05）; the T2 value of proximal-end injured sciatic nerves increased on 3rd day, FA value decreased and returned to normal at 1 week, without statistically significmlt differences compared with the normal side. The T2 mid FA values were highly correlated with the nerve function scores （r=0.884 mid 0.975, P〈0.05）. Conclusion T2 mapping and DTI sequences can qumltitatively determine the injury of sciatic nerve mid can be used to evaluate the chmlges of sciatic nerve injury in rabbits.