超急性期脑梗死CT灌注与病理表现相关性实验研究

An experimental correlation of perfusion CT with pathology in hyperacute cerebral infarction

目的研究兔的脑梗死模型在脑梗死超急性期各时间段CT灌注(CTPI)与病理的相关性,从而发现CT灌注图像变化所代表病理变化规律。方法新西兰白兔42只,采用改良O’Brein法制作局灶性脑缺血模型,分别于术后0.5、1、2、3、4、6h进行CT灌注扫描,获得6幅伪彩功能图像并对大脑双侧对称性ROI的rCBF、rCBV、rTS、rTP进行计算,测量并计算缺血区的相对面积。在各时间段取兔脑组织进行切片,分别进行TTC染色和电子显微镜观察。结果(1)从缺血0.5h开始,血流功能图上可见缺血灶;(2)随着缺血时间的延长rCBF、rCBV不断下降,rTP、rTS开始延长,然后在中区变为0;(3)缺血中心区面随着缺血时间的延长呈现出不断扩大的趋势,缺血边缘区面积随时间延长,在CBF图上逐渐减小,在TP图上逐渐增大,而在TS图上无明显变化;(4)超微结构变化:缺血中心区在缺血4h前是细胞水肿表现;4h后细胞核固缩或结构消失,边缘区表现为细胞水肿。结论CTPI与病理表现有很好的对应性,是诊断超急性期脑梗死比较敏感、稳定、可靠的技术。

Objective To reveal the rules of peffusion maps changing and guide early diagnosis of hyperaeute cerebral infarction. Methods Acute focal cerebral isehemia models were presented in 42 New Zealand rabbits with modified O＇ Brein method. Dynamic scans were performed at 0. 5,1,2,3,4,6h separately after operation by CT scanner. Six cerebral blood functional perfusion maps were obtained, rCBF, rCBV, rTP, rTS of bilateral symmetric interesting regions were calculated. The relative isehemic areas were measured. After CT scanning, rabbits cerebral tissues were obtained and observed by electron microscope. Results At 0.5h after cerebral isehemia,the functional map could show hypoperfusion areas;The rCBF and rCBV of ischemic cores and peri-ischemie areas decreased subsequently along with times of ischemia developing. rTP and rTS increased along with the times, then which of ischemie cores decreased to 0 ; Areas of isehemic cores increased in all perfusion maps along with the time developing. Peri-ischemie areas changed differently on different maps;Before 4 hours after ischemia the cell edema could be shown by electron microscope on the ischemie cores and cell karyopyenosis eould be found after 4 hours. The cell edema could only be observed on peri-isehemie areas. Conclusion CTPI appearanees correspond well with pathologic findings. CTPI is a sensitive, stable, reliable technique to diagnose the hyperacute cerebral infarction.