猫闭合性创伤性脑水肿扩散加权成像的实验研究

The Experimental Study of Diffusion-weighted Imaging in the Brain Edema after Cat Acute Closed Traumatic Brain Injury

目的建立猫急性闭合性脑创伤(TBI)模型,并应用扩散加权成像(DWI)探讨伤后脑水肿类型及演变规律。方法共选取22只猫,以最大角加速度(6.43±0.15)×105rad/s2制成TBI模型,其中10只用于常规MRI及DWI扫描,连续观察伤前及伤后3、6、24、48、72 h 6个时相点,另于上述相同6个时相点,分别选取6只猫用于HE及嗜银染色、6只猫用于透射电镜观察。结果常规MRI显示蛛网膜下腔出血1例、硬膜外或硬膜下出血2例、脑挫裂伤2例、脑室内出血1例、同时显示蛛网膜下腔出血和脑挫裂伤2例、同时显示硬膜下出血和脑实质内点状出血2例。10只猫致伤前后各时点ADC值显示细胞毒性及血管源性两种类型脑水肿,其中7只(70%)猫以细胞毒性脑水肿改变为主,24 h达峰值;3只(30%)猫早期以血管源性脑水肿改变为主,6 h达峰值,而后期以细胞毒性脑水肿为主。HE、嗜银染色及透射电镜显示血管通透性增加、细胞肿胀,轴索肿胀、断裂、轴索球形成。结论猫急性闭合性创伤性脑水肿包括细胞毒性及血管源性两类,以细胞毒性水肿为主。扩散加权成像是观测脑水肿的一种可靠方法。

Objective To investigate the types and rules of brain edema after acute closed traumatic brain injury（TBI） in cats,using diffusion-weighted imaging（DWI）.Methods Ten cats models of TBI were made with an angular acceleration rotating device,study the changes of apparent diffusion coefficient（ADC） before injury and after injury 3h、6h、24h、48h and 72h on different time points.Another 12 cats models were made for observation under light microsope and transmission electron microscope.Results The changes of ADC in the 10 cats revealed two types of brain edema,main changes of cytotoxic brain edema were observed in 7 cats and reached peak at 24h;main changes of vasogenic brain edema were observed in 3 cats and reached peak at 3h,which developed into main changes of cytotoxic brain edema gradully.Conclusion The types of brain edema after acute closed TBI include cytotoxic brain edema and vasogenic brain edema,and cytotoxic brain edema is the main characteristic of brain edema after TBI.DWI is one reliable method in study brain edema.