USPIO增强MRI检测兔动脉粥样硬化斑块的实验研究

目的:探讨USPIO增强MRI检测兔动脉粥样硬化(AS)斑块的可行性及价值.方法:健康雄性新西兰大白兔30只,随机分为实验组20只,对照组10只.实验组采用球囊导管损伤主动脉内膜结合高脂饮食的方法建立兔动脉粥样硬化模型,对照组不做干预.观察USPIO增强前后AS斑块MRI信号表现,并与病理检查结果行对照研究.结果:12例兔AS模型成功建立,扫描范围内共发现普鲁士蓝染色阳性斑块67个,USPIO增强前后信号明显改变者共53个.USPIO增强T_2WI及T_2~*WI表现为斑块中央信号减低,其负性强化峰值出现在注射对比剂后96h.USPIO增强3D-TOF序列表现为管壁点状充盈缺损.病理检查发现,氧化铁颗粒主要沉积在内膜下、泡沫细胞中以及泡沫细胞融合崩解的粥样坏死物中.结论:USPIO增强MRI能检出并反映兔动脉粥样硬化斑块成分,有望用于对AS病变诊断及斑块稳定性的评估.

Experiment Study of USPIO Enhanced MRI in the Detection of Atherosclerotic Plaques in Rabbits

Purpose: To explore the feasibility and value of USPIO enhanced MRI in the detection of atherosclerotic plaques in rabbits. Methods: Thirty New Zealand male rabbits were randomly divided into two groups: experiment group (10) and control group (5). Animal model of atherosclerosis was induced with aortic balloon endothelial injury and high - fat diet feeding. There was not any intervention with the rabbits in control group. MRI findings of atherosclerotic plaques before and after the injection of USPIO were analyzed.A correlative study was done between MRI and pathological findings. Results: Animal model of atherosclerosis was successfully maken in 12 rabbits. There were 67 plaques that were positive on Prussian blue staining within the MRI scanning scope, among which 53 plaques demonstrated obvious change before and after USPIO administration. The central area of the plaques demonstrated decreased signal on USPIO enhanced T_2 WI and T_2~* WI and the peak of the negtive enhancement occurred 95 hours after the injection of USPIO. The plaques showed a dot - like filling defect on USPIO enhanced 3D - TOF image. Ferric oxide particles mainly locallsed under the endomembrane of the vessel, in the foam cells and atheronecrosis area induced by the disaggregation of foam cells on pathologic inspection. Conclu-sion: USPIO enhanced MRI can find the plaques and reveal the component of AS plaque, which could be complied in the diagnosis and evaluation of the stability of AS plaques.