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目的在MR连续观察下,采用自制超小超顺磁性氧化铁(ultrasmall superparamagnetic iron oxide,USPIO),与钆喷酸葡胺(Gd-DTPA)对比,分别对动脉粥样硬化(AS)兔行增强MR检查,旨在探讨USPIO增强MR对AS兔的价值。材料与方法35只雄性新西兰大白兔随机分为两组,25只给予高脂饮食诱导动脉粥样硬化,10只给予正常饮食作为对照组。所有扫描均在1.5 T磁共振扫描仪上进行,采用Cardiac线圈。扫描序列包括:T1WISE,T1WI SE脂肪抑制,T2WI FSE,T2*WI GRE。所有动物于喂养10周时测血清总胆固醇量,并进行平扫及USPIO增强24 h扫描,1周后行Gd-DTPA增强扫描,完成Gd-DTPA增强扫描当天处死不同喂养阶段模型兔及同期对照组正常兔,整个过程每2周重复一次。USPIO使用剂量为0.05 mmolFe/kg体重,Gd-DTPA使用剂量为0.25 mmol/kg体重。MR所见与病理相对照。结果喂养10周时模型兔血清总胆固醇值明显高于正常组(P<0.05),且所有模型兔大体标本均发生肉眼可见动脉粥样硬化样改变,除5只模型兔喂养中途死亡,其余兔均完成全程扫描。病理证实斑块内巨噬细胞吞噬USPIO。USPIO增强MR较Gd-DTPA增强能更好识别斑块内各种成分。结论US-PIO增强MR对识别斑块成分具有独特价值,并能反映斑块内炎性浸润,因此对判断斑块易损性优于Gd-DTPA增强MR。
OBJECTIVE To observe the effect of ultrasound on the development of atherosclerosis (AS) rabbits under ultrastructural ultramagnetic iron oxide (USPIO) in comparison with Gd-DTPA. MR examination to investigate the value of USPIO in enhancing MR in rabbits. MATERIALS AND METHODS: Thirty-five male New Zealand white rabbits were randomly divided into two groups: 25 were given atherogenic diet induced by high fat diet and 10 were given normal diet as control group. All scans were performed on a 1.5 T MRI scanner using a Cardiac coil. Scanning sequences included: T1WISE, T1WI SE fat suppression, T2WI FSE, T2 * WI GRE. All animals were fed with serum total cholesterol at 10 weeks, and the plain scan and USPIO enhanced 24 h scan, 1 week after Gd-DTPA enhanced scan to complete Gd-DTPA enhanced scan the day of the different feeding stages of model rabbits and the control group was normal Rabbit, the whole process is repeated every 2 weeks. USPIO dose of 0.05 mmolFe / kg body weight, Gd-DTPA dose of 0.25 mmol / kg body weight. MR findings and pathological contrast. Results Serum total cholesterol in model rabbits at 10 weeks of feeding was significantly higher than that in normal rabbits (P <0.05). In all the rabbits, the appearance of atherosclerotic lesions was observed in macroscopic specimens. Except for 5 rabbits, Complete the full scan. Pathology confirmed that macrophages within the plaques engulf USPIO. USPIO enhanced MR is better identified than Gd-DTPA in identifying various components within the plaque. Conclusion US-PIO-enhanced MR has unique value for identifying plaque components and can reflect inflammatory infiltrates in plaques. Therefore, US-PIO-enhanced MR is superior to Gd-DTPA-enhanced MR in judging plaque vulnerability.