犬肺缺血再灌注损伤的CT表现及其病理生理学基础

目的评价闭胸式球囊栓塞法制备犬肺缺血再灌注模型的CT表现及其病理生理学基础。材料与方法选用健康杂种犬11只,球囊栓塞犬左下叶肺动脉2 h,然后撤出球囊,建立肺缺血再灌注模型,分别于栓塞前、栓塞2 h、再灌注1 h、2 h、3 h、4 h分别行CT平扫,同时测量肺动脉主干的压力,抽取静脉血及动脉血做血常规及血气分析,再灌注4 h行CT扫描后处死犬得到肺病理标本,进行病理学检查。分析其动态影像学表现、肺动脉压、血气结果及组织病理学表现。结果 10只犬模型制作成功,8只犬数据完整纳入最终分析。栓塞前8只犬双肺未见明显异常。栓塞2 h,8只犬均表现为左肺透亮度增加,右肺均出现不同程度的"毛玻璃征"。再灌注过程中,8只犬双肺均出现不同程度"毛玻璃征",持续4 h后仍未恢复正常;非栓塞侧肺组织改变无规律的变化趋势;而栓塞侧肺组织再灌注3～4 h时病变程度最重(n=7)。综合评价6个时间点,4只犬左肺病变略重于右肺,4只犬右肺病变略重于左肺。病理学检查见双肺均出现肺毛细血管充血,肺泡间隔增宽,其中4只犬左肺病理改变重于右肺,4只犬左肺病理改变比右肺轻;与上述影像学表现吻合。犬栓塞后至再灌注后4 h持续存在低氧血症和酸碱平衡紊乱,但整体上栓塞前后至再灌注后4 h肺动脉压、血气分析结果的差异无统计学意义(P>0.05),综合分析显示再灌注过程中3 h时机体病理生理学改变最重。结论闭胸式球囊栓塞法制备的犬肺缺血再灌注损伤在CT像上主要表现为双肺轻重不一的"毛玻璃"样改变,持续至再灌注4 h后仍未恢复正常,可能与肺毛细血管扩张充血、低氧血症和酸碱平衡紊乱等病理生理学改变相吻合。

CT Findings of Lung Ischemia Reperfusion Injury in Canine:Correlation with Pathophysiology

Objective To evaluate CT findings and associated pathophysiological basis of pulmonary ischemic reperfusion injure(PIRI) in dog models with the closed pectoral balloon embolization method.Materials and Methods Eleven health hybrid dogs were selected for establishing PIRI model.Right femoral vein was punctured with Seldinger method and left pulmonary artery was blocked with the balloon for 2 hours.CT plain scan was performed,pulmonary arterial pressure were measure and blood sample was collected at 6 time points,including pre embolisation,2 h after establism,1 h,2 h,3 h,4 h after reperfusion.Immediately after CT scan at 4 h after reperfusion,the dogs were sacrificed and lung specimens were harvested.Dynamic CT findings,pulmonary artery pressure,blood gas results and histopathological findings were analyzed.Results PIRI models were successfully made in 10 dogs,8 dogs were induced into final analysis.Bilateral lungs were normal on pre embolisation CT images.At 2h after embolisation,the left lungs had decreased opacification and the right lungs occurred different degree of ground glass opacification in 8 dogs.During reperfusion process,bilateral lungs appeared to different degree of ground glass opacification in 8 dogs,and did not recover until 4h after reperfusion.The contralateral lung did not show homogeneous change after reperfusion,while the embolized lungs showed the most serious damage at 3-4 h after reperfusion(n=7).Comprehensive evaluation showed the left lung lesions were slightly heavier than the right lung in 4 dogs,the right lung lesions slightly heavier than the left lung in other 4 dogs.Pathological examination showed the widened alveolar interval and hyperemia capillaries in bilateral lung tissues.Pathological findings agreed with CT imaging on severity of lung lesions.Continuous hypoxia and acid base disorders were represented during PIRI.But from embolisation to 4h after reperfusion,blood gas results had no statistically significant(P>0.05),comprehensive analysis showed the pathophysiological changes were worst at 3 h after reperfusion.Conclusion Different degree of ground-glass opacification was main CT finding of PIRI in canine models,which will persist at least 4h after reperfusion.These CT findings were concord with pathophysiological changes,such as pulmonary capillary hyperemia,hypoxemia,and acid base disorders.