脑出血周围组织脑血流变化CT灌注成像与早期缺血性损伤的动物实验

CT perfusion imaging of perihematomal cerebral blood flow and early ischemic injury in experimental intracerebral hemorrhage

目的 探讨血肿周围局部脑血流变化与周围组织早期缺血性损伤的关系。方法 雄性SD大鼠70 只,随机分为注血组和对照组,采用自体血注射法制备大鼠脑出血模型,利用GE LightSpeed螺旋CT扫描机灌注成像及计算机辅助系统制作大鼠脑CT灌注参数图,对血肿周围局部脑血流量(rCBF)、局部脑血容量(rCBV)和对比剂平均通过时间(MTT)脑血流动力学参数进行定量测量,并与大鼠脑TTC染色和HE 染色进行比较。结果 血肿周围存在不同程度低灌注,低灌注梯度依色阶变化表现为多层彩色环绕带,呈“靶样”改变;血肿周围局部脑血流量呈波动性改变,血肿周围rCBF和rCBV在注血后1 h降至最低,其后逐渐回升。TTC染色血肿周围未见白色梗死区;HE 染色可见血肿周围组织疏松,细胞不同程度水肿,星形细胞肿胀,神经细胞变性。结论 大鼠脑注血后血肿周围局部脑血流显著降低可引发周围组织早期缺血性损伤,CT灌注成像可在活体下显示血肿周围异常的脑血流动力学变化,可为脑出血临床救治提供有价值信息。

Objective To investigate the relationship between the changes of regional cerebral blood flow and the ischemic injury in the early stage after intracerebral hemorrhage (ICH) in rats. Methods Seventy male Sprague-Dawley rats were randomly divided into ICH group and sham-operated group. ICH was produced by microinjection of fresh autologous blood into the right caudatum in rats. CT perfusion imaging and computer aided mapping in measurements of regional cerebral blood flow adjacent to the hematomas were performed in rats. The parameters of regional cerebral blood flow (rCBF), regional cerebral blood volume (rCBV) and mean transit time (MTT) were calculated respectively. After the CT examination, the histopathological examination of TTC and HE staining were carried out. Results The gradient of perihematomal hypoperfusion was revealed by rCBF and rCBV maps in ICH groups. The alternation of rCBF around the hematomas was fluctuated, the rCBF and rCBV reduction were most pronounced at 1 hour after ICH, then gradually returned. TTC staining did not show infarction around the hematomas. Histopathological study demonstrated the cellular edema, astrocytic swelling and neuronal degeneration in the peri-ICH regions. Conclusion The perihemorrhagic ischemic injury can be induced by the pronounced reduction of cerebral blood flow in the early stage of ICH. CT perfusion imaging can clearly demonstrate the abnormal cerebral hemodynamic change occurred in the region surrounding the hematomas in vivo, and can provide valuable information to the clinical treatment after intracerebral hemorrhage.