大鼠急性脑缺血再灌注的磁共振灌注扩散成像与病理对照研究  

Combining Perfusion-Weighted MR Imaging and Diffusion-Weighed MR Imaging in the Evaluation of Rat Acute Cerebral Ischemic and Reperfusion and Histopathologic Correlation

作　　者：鲁宏[1] 胡惠[2] 杨娜[1] 游长永[2] 张小鸽[2] 张凌[2] 夏庆杰[3] 赵建农[1] 

机构地区：[1]重庆医科大学附属第二临床医学院放射科,重庆400010 [2]成都市第二人民医院影像科 [3]四川大学华西医学中心分子遗传学实验室

出　　处：《实用放射学杂志》2007年第10期1409-1412,共4页Journal of Practical Radiology

基　　金：国家自然科学基金资助项目(编号:30471646);重庆市自然科学基金资助项目;编号:渝科发计字[2004]54号

摘　　要：目的探讨急性脑缺血再灌注的磁共振灌注成像(PWI)及扩散成像(DWI)的表现以及其病理改变。方法取70只Wistar大鼠,用线栓法建立右侧大脑中动脉栓塞(MCAO)模型,分为假手术(A组)、栓塞30min及再灌注30min、60min(B、B1、B2组)、栓塞60min及再灌注30min、60min(C、C1、C2组),每组各10只。对各组分别行头部MRI扫描,计算缺血区的DWI异常信号相对面积(rSD)、相对表观扩散系数(rADC)、PWI异常信号相对面积(rSP)、相对平均通过时间(rMTT),将所测值进行比较。对缺血区脑组织进行病理观察。结果实验各组在T1WI、T2WI像上均未见异常信号。A组的DWI和PWI亦未见异常信号。在DWI像上,B、C、B1、B2、C2、C1组在右侧基底节区高信号的范围由小扩大,随后逐渐缩小。在PWI像上,B、C组在右侧基底节区出现明显低灌注信号,在B1、C2组则出现高灌注信号,C1组呈现稍低灌注信号,B2组的信号基本正常。在B、C2组间存在MTT/DWI异常信号不匹配区。病理观察:DWI异常信号区及MTT/DWI异常信号不匹配区均可见细胞器肿胀,提示为半暗带,B1、C1组可见轻度血管源性水肿,B2、C2组未见明显病理改变。结论细胞内水肿是半暗带的病理改变之一,在早期脑梗塞DWI高信号仍提示为半暗带组织,再灌注早期可出现血管源性水肿,再灌注越早脑细胞越容易恢复正常。Objective To investigate the perfusion -weighted MR imaging（PWI） and diffusion -weighed MR imaging（ DWI） features of acute cerebral ischemic as well as its histopathology. Methods Seventy Wistar rats were divided into 7 groups randomly, including control group （A） and occluded and reperfusion groups. The occluded groups were studied after the right middle cerebral artery of the rats unilaterally occluded （MCAO） at an interval of 30 min （ B ） , 60 min （ C ） , after that, the reperfusion operated at an interval of 30 min （ B1 , C1 ） , 60 min（B2,C2） , respectively（n = 10 for each group）. Then all rats were imaged with MRI. The relative areas of the abnormal signal （ rSo , rSp ） ,the relative apparent diffusion coefficient （rADC） , the relative mean transit time（rMTT） were calculated. The cerebral ischemic tissue were examined with histology. Results There was no changes of the signal intensity on T1WI and T2WI in all groups. In group A, DWI and PWI showed no change in the signal intensity, too. Hyper - intensity was found in the cerebral ischemic areas of groups B, C, B1, B2, C1 and C2. The size of the hyper- intensity signal（ rSo ） in DWI along with the extension of occlusion time （B and C）. Meanwhile, it reduced along with the time of reperfusion （ B1, B2 and C2）. On PWI, significant hypo - perfusion of right basal ganglia was shown in groups B and C. Otherwise, significant hyper - perfusion of right basal ganglia was shown in groups B1 and C2. There was no change of signal ingroup B2, slightly hypo - perfusion of right basal ganglia was shown in group C 1 . Tissues which hyper - intensity mismatch region between on DWI and MTT / DWI all shown slight swelling of cel organ in neurons , indicating the existence of ischemlc penumbra zone. The vasogenic brain edema was observed in groups B1 and C1. No histopathological change was found in groups B2 and C2. Conclusion The results imply that the intracelluar brain edema isone of the important pathological chara

关 键 词：脑 脑缺血 缺血半暗带 磁共振成像 扩散 灌注 

分 类 号：R743.31[医药卫生—神经病学与精神病学] R445.2[医药卫生—临床医学]