DTI定量评价大鼠急性创伤性脊髓损伤后功能改变

目的 探讨DTI定量参数动态评价大鼠不同程度急性创伤性脊髓损伤（TSCI）后功能改变的价值。方法 采用改良Allen打击法制备轻度、中度及重度损伤组大鼠急性TSCI模型各10只。于损伤前、损伤后即刻、6 h、24 h、3天、7天及14天分别行DTI检查及运动功能评分（BBB）评分，获得并比较轻、中、重度损伤组大鼠TSCI后不同时间点DTI参数值及BBB评分的差异，分析大鼠BBB评分与各参数间的相关性。结果 轻、中、重度损伤组间和TSCI后不同时间点间FA、MD及RD值差异均有统计学意义（P均<0.05）；TSCI后不同时间点间AD值差异有统计学意义（F=12.720，P<0.001），而轻、中、重度损伤组间AD值差异无统计学意义（F=0.469，P=0.630）。大鼠TSCI后即刻FA、MD值减低，RD值升高，后FA值持续降低，MD和RD值持续升高至24 h （P均<0.05），24 h后趋于稳定（P均>0.05）。大鼠BBB评分损伤后即刻降至最低值，之后持续上升（P均<0.05），且BBB评分与MD相关性最高（r=0.958，P<0.01）。结论 DTI可动态定量评价大鼠TSCI后功能改变；推测TSCI后1天之内可能为治疗最佳时间窗。

DTI quantitative evaluation of functional changes after acute traumatic spinal cord injury in rats

Objective To explore the value of DTI quantitative parameters in evaluating neurological function changes of acute traumatic spinal cord injury (TSCI)in rat models. Methods The modified Allen''s dropping weight technique was used to establish TSCI rat models. Then the rats were divided into mild injury group, moderate injury group and severe injury group (each n=10). DTI examination and Basso-Beattie-Bresnahan (BBB) score were performed pre-TSCI and 0 h, 6 h, 24 h, 3 day, 7 day and 14 day post-TSCI, respectively. The BBB scores and DTI parameters, including FA, mean apparent diffusivity (MD), radial diffusivity (RD) and axial diffusivity (AD) were measured and compared among groups. The correlation between BBB scores and the parameters was evaluated. Results The differences of FA, MD and RD value were statistically significant among varying injury degree groups and different time points after TSCI (all P<0.05). AD value had statistical difference among different time points (F=12.720, P<0.001), whereas no difference was found among varying injury degree groups (F=0.469, P=0.630). FA and MD values decreased while RD increased 0 h post-TSCI. Then RD and MD increased continuously, whereas FA decreased continuously until 24 h post-TSCI (all P<0.05), and the parameters kept stable after 24 h post-TSCI (all P>0.05). The BBB scores were lowest on 0 h post-TSCI, then maintained increasing (all P<0.05). In addition, the BBB scores and MD values had good correlation (r=0.958, P<0.01). Conclusion DTI can quantitatively evaluate function changes of TSCI in rat models. Moreover, treatment within 24 h post-TSCI might be recommended for TSCI therapy.