CT灌注成像诊断大鼠超急性脑梗死

CT perfusion imaging in the experimental ultra-acute cerebral infarction in rats

目的应用CT灌注成像技术观察大鼠超急性脑梗死脑血流动力学变化及缺血半暗带的演变,为临床早期诊断治疗提供依据和指导。方法雄性成年Wistar大鼠,随机分为缺血组(n=24)及假手术组(n=6)。各组术后6h内,每间隔1h分别行CT灌注扫描及TTC、HE染色。结果缺血组CTPI表现:①梗死中心区CBF、CBV较对侧明显减低,MTT明显延长,差异有统计学意义(P<0.05);IP区CBF较对侧减低明显(P<0.05)。②梗死中心区缺血1h、2h与3h、4h、5h、6h比较rCBF、rCBV及MTT变化明显,差异有统计学意义(P<0.05)。③梗死中心区与IP区、周围正常组织区比较,rCBF、rCBV及MTT差异有统计学意义(P<0.05);IP区较周围正常区rCBF差异有统计学意义(P<0.05)。④梗死中心区梗死面积随缺血时间延长扩大,1h、2h与3h、4h、5h、6h比较差异有统计学意义(P<0.05),同一时间点不同样本之间梗死体积的差别与CBF减低的程度关系密切。假手术组:在CTPI及HE染色均表现阴性。缺血组HE染色表现:缺血1h、2h、3h血管间隙增宽,神经细胞水肿;4h、5h、6h,神经核固缩,血管周围大量空泡状改变。结论CTPI检查无创、简单快捷,可以在超急性脑梗死实验中及时、准确显示梗死及IP的部位及范围,并定量分析其血流动力学变化情况,大大缩短了治疗时间窗,为临床治疗提供有力的依据。

Objective To observe brain hemodynamic changes and the development of ischemic penumbra（IP）of rats with ultra-acute cerebral infarction using CT perfusion imaging（CTPI）.Methods Twenty-four ischemia adult male Wistar rats and 6 controls underwent CTPI and TTC,HE staining within 6 h of stroke onset once an hour.Lesion volumes were measured on MTT,CBV,and CBF maps with region-of-interest analysis and were compared with follow-up CT volumes with correlation and regression analysis.Results At the central area of infarction,the CBF and CBV were lower than those of the contralateral area,and MTT was prolonged（P〈0.05）.At the central area of ischemic infarction,the rCBF,rCBV and MTT changed significantly at 1 h,2 h compared with the 3 h,4 h,5 h,6 h（P〈0.05）.There were significant differences in rCBF,rCBV,MTT between the central area of infarction and the penumbra,the area around the normal comparison（P〈0.05）,also in rCBF about penumbra compared with the area around the normal（P〈0.05）.The infarction central area expanded significantly with the time prolonged,and there were significant differences in infarction central area between 1 h,2 h and 3 h,4 h,5 h,6 h（P all〈 0.05）.The difference of infarction volume was closely related to the reduction of CBF at the same point.CTPI and HE staining were negative in the sham group.At 1 h,2 h,3 h point,blood vessels gap widened,the nerve cells edema mild.Nucleus condensated at 4 h,5 h,6 h points,and there was great quantity of vacuoles around blood vessels.Conclusion The use of CTPI in the triage process has been driven by the rapidity and wide availability of this imaging technique.CTPI can show the scope and site of cerebral infarction and penumbra at ultra-acute period,the homodynamic changes with quantitative analysis,and reduce the treatment time window significantly.