实验性脑弥漫性轴索损伤的磁共振波谱研究

目的 建立SD大鼠脑弥漫性轴索损伤(DAI)模型，探讨磁共振波谱(MRS)对DAI的早期诊断价值及前景。方法 雄性SD大鼠20只，自由落体法复制弥漫性脑轴索损伤动物模型，分别于损伤前及损伤后4h、8h、24h、48h行MRS检查，观察NAA／Cr、Cho／Cr的变化，并与病理对照。结果 打击后24h即可见轴索损伤的病理表现；MRS示轴索损伤后NAA／Cr4h显著下降；8h起逐渐恢复上升，但48h又明显下降；而Cho／Cr变化无显著差异。结论 DAI急性期可能存在短暂可恢复的时间窗。MRS有望为DAI的早期诊断、预后和疗效判断提供有效指标。

Magnetic resonance spectroscopy of experimental diffuse axonal injury

Objective To set up a model of diffuse axonal injury(DAI) in SD rats and to assess the value and prospect of magnetic resonance spectroscopy(MRS)in early diagnosis of DAI.Methods DAI model was established in 20 male SD rats utilizing a weigh-drop device,and MRS was performed before trauma and after trauma for 4,8,24,48 hours.The ratio of N-acetylaspartate/creatine(NAA/Cr)and choline/creatine (Cho/Cr)were calculated and correlated with pathological findings respectively.Results Axonal changes were confirmed in microscopic study 24 hours after injury.The ratio of NAA/Cr decreased drastically at 4 hours after trauma,followed by a steadily recover at 8 hour,and decline again at 48 hour,though the ratio of Cho/Cr had no significant change.Conclusion There may be a reversible narrow time-window in acute phase of DAI.MRS would play a positive role in early diagnosis,prognosis and follow-up of DAI.