目的 探讨3.0T高分辨MRI对兔腹主动脉粥样硬化模型药物诱发斑块破裂和血栓形成的成像研究.方法 20只雄性新西兰白兔,采用数字表法随机分为实验组16只,对照组4只,采用间断高脂饲料喂养结合球囊拉伤腹主动脉技术建立动脉粥样硬化模型,并在建模3个月后给予蝰蛇毒+组胺药物诱发试验,以期斑块破裂和形成血栓.在药物诱发试验前后分别行腹主动脉的多序列高分辨3.0T MR成像,包括三维时间飞跃法血管成像(3D TOF)、T1WI、T2WI及对比增强扫描,最后处死动物获得主动脉的大体病理和组织学资料.分析MRI检查结果,采用Pearson相关检验比较MRI测量的血栓位置、长度与组织病理学结果的相关性.利用方差分析及LSD-t检验回顾性比较血栓形成亚组和无血栓形成组动物.结果 在药物诱发实验后,存活的14只实验组兔中8只成功诱发斑块破裂并血栓形成,对照组无血栓形成,多序列MRI检查显示其对血栓数量的诊断准确性为87.1% (27/31).MRI测量的血栓位置(r=0.94,P<0.01)和血栓长度(r=0.85,P<0.01)均与大体组织学测量的相应参数呈正相关.管腔狭窄更易诱发斑块破裂和血栓形成,有血栓组管腔面积是(5.71±2.38)mm^2,无血栓组为(8.93±5.36) mm^2,差异有统计学意义(P<0.01).结论 高分辨MRI能无创性评估动物模型斑块破裂和血栓形成.
Objective To explore the imaging of the thrombosis after pharmacological triggering of plaque rupture in atherosclerotic rabbit model by using 3.0 T high-resolution magnetic resonance imaging.Methods Twenty male New Zealand white rabbits were divided into an experimental group (n = 16) and a control group (n = 4).The aortic wall injuries were induced by an intravascular balloon in experimental group rabbits after high cholesterol diet.The pharmacological triggering with Russell's viper venom and histamine was performed after 3 months of establishment of model.All of the animals underwent pre-trigger and post-trigger MR examinations including 3D time of fight (3D TOF),T1 WI,T2WI and post contrast T1 WI.Euthanasia was performed in all rabbits and gross anatomy and histological specimen of aorta were obtained.Comparing the location and length of the thrombus between MRI images and histopathology was used Pearson test.Comparing the calculated indexes of abdominal aorta between rabbits with and without thrombosis was used AVONA test and LSD-t test.Results After triggering,8 in 14 survived rabbits developed thrombosis in experimental group,meanwhile,no thrombus was found in control group.The accuracy of multi-sequences MRI for detecting of thrombus was 87.1% (27/31).MRI data correlated with the histopathology regarding thrombus length ( r = 0.85,P 〈 0.01 ) and thrombus location ( r = 0.94,P〈0.01 ).Compared with rabbits without thrombosis,the rabbits with thrombosis had narrower lumen of abdominal aorta in the pre-triggered MR images [ ( 5.71 ± 2.38 )mm^2 vs.( 8.93 ± 5.36) mm^2,P 〈 0.01 ].Conclusion MRI is useful tool to determine the thrombosis and plaque rupture in atherosclerotic rabbit model.