目的:制作兔坐骨神经急性牵拉伤可逆损伤模型,探讨纤维示踪成像(DTT)评价坐骨神经急性牵拉伤的可行性及准确性。方法:选取32只新西兰白兔,牵拉右侧坐骨神经建立退变与修复模型;左后肢为假手术侧。于术后1、3 d及1、2、3、4、6、8周行MR扩散张量成像并行纤维示综,测量神经纤维束长度及平均神经纤维密度指数。MRI检查完毕,于各时间点取1只兔坐骨神经行病理检查。结果:坐骨神经牵拉伤术后1 d~2周损伤侧纤维束长度与假手术侧有明显差异(P<0.05);3~8周损伤侧坐骨神经纤维束长度与假手术侧无明显差异。术后1 d~8周损伤侧平均神经纤维密度指数与假手术侧有明显统计学差异(P<0.05);牵拉伤后1 d牵拉段可见较多髓鞘扭曲,3 d牵拉段轴索明显崩解。2周神经退变与再生并存,8周神经纤维再生基本成熟。结论:神经纤维束长度及平均神经纤维密度指数~时间曲线与病理学的变化趋势相一致,可作为评价神经损伤退变及再生的补充手段。 Objective: To develop a reversible injury model of acute traumatic nerve injury in rabbits, and to evaluate the feasibility and accuracy of using DTT to evaluate acute traumatic injury of sciatic nerve. Methods: Thirty-two New Zealand white rabbits were selected and the right sciatic nerve was pulled to establish the model of degeneration and repair. The left hind limb was sham operated. MR diffusion tensor imaging parallel fiber enumeration was performed on the 1st, 3rd, 3rd, 4th, 6th and 8th postoperative weeks to measure the length of the nerve fiber bundle and the mean nerve fiber density index. MRI examination was completed, at each time point to take a rabbit sciatic nerve pathological examination. Results: There was a significant difference between the injured side and the sham side 1 and 2 weeks after sciatic nerve injury (P <0.05). There was no significant difference in the length of injured side sciatic nerve bundle between 3 and 8 weeks after operation. The mean nerve fiber density index on the injured side was significantly different from that on the sham-operated side (P <0.05) at 1 d to 8 weeks after operation. More distraction of myelin was observed on 1 d after traction injury and 3 d on the distraction Axles clearly disintegrated. 2 weeks of nerve degeneration and regeneration coexist, 8 weeks of nerve fiber regeneration is basically mature. Conclusion: The length of nerve fiber bundles and average nerve fiber density index ~ time curve are consistent with the pathological changes, which can be used as a supplementary method to evaluate the degeneration and regeneration of nerve injury.