大鼠局灶性脑缺血模型的氧代谢功能磁共振成像研究  

Research on oxygen-metablism functional MR imaging of rat's regional cerebral ischemia model

作　　者：龚万庆[1] 陶晓峰[1] 高欣[1] 姚建华[1] 王霞[1] 

机构地区：[1]上海长征医院影像科,上海200003

出　　处：《中国医学影像技术》2007年第12期1757-1760,共4页Chinese Journal of Medical Imaging Technology

基　　金：上海市科委重点课题(034119836);上海市卫生局课题(024003);长征医院"三重三优"学科人才计划优秀青年技术骨干项目

摘　　要：目的应用氧代谢功能磁共振成像对线栓法建立的大鼠局灶性脑缺血模型进行实验研究,以明确该技术对脑缺血的评价作用。方法14只350～450g Sprague-Dawley大鼠（其中雄性12只,雌性2只）,扫描采用GEsigna HD1.5T双梯度超导磁共振仪。大鼠仰卧头部放置于3英寸环形相控阵线圈中央,口内置入塑料氧管约3～4cm,以胶贴固定于口部周围,留出鼻孔位置,于每次采集时相开始时开放纯氧10s,氧流量为8L/h,模拟正压通气状态。于大鼠一侧大脑中动脉栓塞后1、2、5、8、12、24、48h行DWI和BOLD-fMRI扫描,运用GE工作站Functool软件获得BOLD-fMRI感兴趣区（ROI）信号变化曲线,其信号强度升高为正性激活,减低为负性激活。在氧含量异常的区域指定感兴趣区以显示其灌注曲线,并将DWI和BOLD-fMRI检查结果与病理观察对比。结果14只实验大鼠中11只成功完成检查。完成检查的大鼠栓塞后1h,梗死区DWI显示轻微信号异常,fMRI显示正常鼠脑组织和梗死区的信号均为明显负性激活;栓塞后2h,DWI明显异常,fMRI显示正常鼠脑组织的信号为明显负性激活,梗死区则表现为明显的正性激活;栓塞后5、8、12h fMRI显示正常鼠脑组织和梗塞区的信号为明显负性激活,但信号强度随时间递减。栓塞后48h显示正常鼠脑组织为负性激活,梗塞区信号强度曲线杂乱,无明显激活。病理切片符合相应时间内梗死的表现。结论氧代谢功能磁共振成像能动态观察大鼠局灶性脑缺血后的缺血缺氧改变,这项技术的实验研究对发展和检测fMRI技术、深入研究脑缺血的风险预测具有重要价值。Objective To study oxygen-metablism functional MR imaging on rat＇s regional cerebral ischemia model and evaluate the use of this technique on cerebral ischemia. Methods Fourteen Sprague-Dawley rats weighting 350-450 g with unilateral middle cerebral artery occlusion （MCAO） examined with GE signa HD 1.5 T scanner （Male： twelve; Female： two）. Rats fixed with nasal opening free are backlying in the middle of phased-array coil with a plastic tube of 3-4 cm at the inner entrance. Oxygen is supplied when each activation phase starts with 8 L/h lasting for 10 s. DWI and BOLD-fMRI series are performed 1, 2, 5, 8, 12, 24, 48 h respectively after unilateral focal cerebral＇ischemia. The curve of region of interest （ROI） of BOLD-fMRI was analysised with Functool from GE. The signal rises with positive activation and reduces with negative activation. To show the TI-C of regions of abnormal oxygen content on BOLD-fMRI and compare the results of DWI and BOLD-fMRI with pathological findings. Results Eleven examinations were successfully done. One hour after the blockage DWI shows minor abnormal signal, while fMRI shows obvious negative activation in both normal and infarction areas （P〈0.01）. Two hours after blockage, DWI shows significant abnormal signal, fMRI shows obvious negative activation in normal areas and obvious positive activation in infarction areas （P〈0.01）. Five, 8, 12 hours after blockage, fMRI shows obvious negative activation in normal areas （P〈0. 01）, with signals descending with time. Pathological finding prove the corresponding infarction manifestations. Conclusion Oxygen-metablism MRI functional imaging is useful to observing changes of rat＇s regional cerebral ischemia. This technique is of great value for the development of fMRI and risk estimation of cerebral ischemia.

关 键 词：脑功能成像 磁共振成像 动物实验 氧代谢 

分 类 号：R445.2[医药卫生—影像医学与核医学]