论文部分内容阅读
目的阻断狗大脑中动脉建立急性脑梗塞动物模型，观察早期ＭＲＩ表现及其病理改变。材料与方法将１６只成年狗随机分为实验组（１０只）和对照组（６只）。经颞开颅阻断一侧大脑中动脉（ＭＣＡ），造成其供应区急性缺血性脑梗塞，术后２，４，６，８，１２小时行ＭＲＩ薄层扫描；取出动物大脑观察病理改变，测定不同时相梗塞区Ｔ２时间和组织水含量。结果ＭＲＩ最早２小时表现异常，Ｔ２加权像可见尾状核头部、豆状核信号增高；桓塞６小时，ＭＲＩ可见尾状核、豆状核形成明确梗塞，并出现占位征象。梗塞２小时，电镜下已有缺血水肿改变，４小时光镜下出现脑缺血水肿改变，电镜下见血脑屏障受损。相关分析表明：病灶区Ｔ２时间变化与组织水含量变化在时序上有密切关系，经 ｔ检验差别具显著意义（Ｐ＜０．０１）。结论本项实验结果表明，ＭＲＩ可用于脑梗塞早期的诊断，在显示病灶方面，ＭＲＩ Ｔ２加权像优于Ｔ１加权像。急性脑梗塞早期 ＭＲＩ表现的病理基础是脑水肿。
OBJECTIVE: To establish an animal model of acute cerebral infarction by blocking middle cerebral artery (MCAO) in dogs and observe the manifestations and pathological changes of early MRI. Materials and Methods 16 adult dogs were randomly divided into experimental group (n = 10) and control group (n = 6). One side of the middle cerebral artery (MCA) was blocked by temporal craniotomy, which caused acute ischemic stroke in its supply area. MRI thin-layer scanning was performed at 2, 4, 6, 8 and 12 hours after operation. , At different time points infarction area T2 time and tissue water content. Results The first 2 hours of MRI showed abnormalities. The T2 weighted image showed the head of caudate nucleus and the lentiform nucleus signal increased. For 6 hours, the nuclei of caudate nucleus were observed with MRI, and the lentiform nucleus formed a clear infarction with occupying signs. 2 hours after infarction, ischemia-edema had been observed under electron microscope, cerebral ischemic edema changed under light microscope in 4 hours, and blood-brain barrier was damaged under electron microscope. Correlation analysis showed that there was a close relationship between temporal change of lesion T2 and changes of tissue water content in time sequence. The difference was significant (P <0.01) by t test. Conclusion The experimental results show that MRI can be used in the early diagnosis of cerebral infarction, MRI T2-weighted images are superior to T1-weighted images in the display of lesions. The pathological basis of early MRI manifestations of acute cerebral infarction is cerebral edema.