中文摘要：

目的探讨纵向弛豫时间、弥散张量成像和波谱在评价兔失神经靶肌肉退变及再生的价值。方法将36只新西兰大白兔随机分成模型组（32只,白兔右后肢制作失神经支配骨骼肌退变及再生模型,左侧为假手术侧）和对照组（4只）,所有白兔分别于术后1 d、3 d,1、2、3、4、6、8周对靶肌肉进行T2图、弥散张量成像和波谱及病理检查,每时间点4只,测量不同时间点T2值、弥散张量参数、波谱参数及病理学变化特点。结果 32只兔造模成功,术后第1天,失神经靶肌肉波谱areaTMA、areacr、HighTMA、Highcr开始上升,弥散张量参数λ∥值、λ⊥值及FA值开始下降,以λ∥值最显著,与术前比较有统计学差异（P〈0.05）,病理上靶肌肉肌纤维间质出现水肿;3 d~4周,areaTMA、areacr、HighTMA、Highcr继续上升,λ∥值、λ⊥值及FA值继续下降,T2值开始轻度延长,T2值、大部分波谱及弥散张量参数在4周时到达峰值;而病理上则有血管扩张、充血淤血、渗出、肌纤维灶性萎缩、肌肉间隙增宽的出现;6~8周,上述指标均缓慢恢复,相对应病理改变逐渐减轻。经LSD法进行组间对比,T2值、FA值、λ∥、λ⊥及areaTMA与对照组有统计学差异的分别为3 d~8周,1 d~6周,1~6周,1~6周及3 d~2周（P〈0.05）。结论 MR T2值、弥散张量和波谱均能有效评价失神经靶肌肉退变及再生的情况,三者参数的变化规律和失神经靶肌肉的病理学变化趋势相一致,λ∥值是所有指标中最敏感的指标,敏感度比较从高到低依次是弥散张量成像、波谱、T2值。

英文摘要：

Objective To compare the denervation and reinnervation of rabbits by T2 value,diffusion tensor imaging and spectroscopy. Methods Thirty-six New Zealand white rabbits were randomly divided into the traction injury group（ 32 rabbits, the right posterior limb was made the model of denervation and reinnervation by tracting sciatic nerve,the left side was set as the sham operation side）and the control group（ four rabbits）. Conventional MRI sequences,diffusion tensor imaging,spectroscopy and histology were performed for all the target muscles preoperatively,and performeed again one day,three days,one weeks,two weeks,three weeks,the 4th week,six weeks,and eight weeks（ n = 4 each time point） after the surgery; meanwhile,T2,FA,ADC,λ∥and λ⊥,areaTMA,areacr,HighTMA,Highcrvalues were measured in the denervation muscle and the pathological feature were observed. Results All the rabbit models were successfully made. areaTMA,areacr,HighTMA,Highcrbegan to increase and λ∥,λ⊥and FA began to decrease when the muscle fibers of the target muscle developed interstitial edema on the first day after the denervation and reinnervation model was prepared. λ∥value decreased markedly and the difference was significant comparing with the preoperative data（ P〈0. 05）. areaTMA,areacr,HighTMA,Highcrincreased gradually and λ∥,λ⊥and FA decreased gradually,meanwhile T2 value prolonged slightly; the spectroscopy data and the diffusion tensor imaging data reached the peak values in four weeks,and the histological observation showed vasodilation,congestion,exudation,focal atrophy of muscle fibers and muscle gap widened from the 3 rd day to 4 th week after the modeling. The values of the parameters above slowly recovered,with the pathological changes gradually alleviated in the following six to eight weeks. According to LSD test,the differences in T2 values,λ∥values,λ⊥values,FA values and areaTMA were significant between the control group and the injury group at the postoperative time of three days to eight we