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方法：动物(兔)随机分为5组，1组正常饮食，另4组给予不同种类的高脂饮食。4周后抽取血标本，测定血脂，包括CHO、TG、HDL、LDL、血糖、血钙等指标，确定造影是否成功。成功后进行IVUS检查。动物麻醉后，股动脉分离穿刺，放置5F鞘管，立即给予肝素100 IU/kg抗凝。自鞘管尾端插入超声导管，在X线透视帮助下，把导管头端放置在不同肋间之下肋上缘对应的胸主动脉处，记录超声影像于录像带上。完毕后，从血管注入空气处死动物。立即取超声观察部位的动脉置入10%福尔马林液中送病理检查。回放录像带观察动脉是否存在粥样硬化及其性质，测量斑块最大厚度。测量内膜及中膜的厚度。病理检查确定动脉有无斑块及斑块性质，用显微镜测微尺测量内膜及中膜的厚度。
结果：和病理相对比，IVUS判断大弹性动脉是否存在粥样硬化二者无显著性的差异，其符合率达94%(IVUS对照组12个血管位点均未发现斑块，病理也示12个位点均正常。实验组33个位点，IVUS发现30个存在脂纹或斑块，3个正常；病理显示32个存在脂纹或斑块，1个正常，P＞0.05)。对斑块厚度的测量，二者相关性较好(r=0.835,P＜0.05),对中膜厚度的测量，二者相关性亦较好(r=0.814,P＜0.05),但对正常血管内膜的测量，二者相关性较差(r=0.055,P＜0.05)。对脂质斑块性质的判断，二者亦无显著性差异，符合率达97%(P＞0.05)。
结论：IVUS能够准确判断血管(弹性动脉)是否存在粥样硬化改变，即使是动脉硬化也能较敏感地发现。更主要的是能够准确判断斑块性质及大小，并能较好地测量内膜的厚度，但却往往大大高估弹性动脉内膜的厚度。
A Qualitative and Quantitative Study of Normal and Atherosclerotic Elastic Arteries with Intravascular Ultrasound (Abstract)
The Heart Center, Beijing Red Cross Chaoyang Hospital,
The Institute of Cardiovascular Disease, Capital University of Medical Sciences, Beijing (100020)
Ni Zhuhua, Zhu Tiangang, Hu Dayi, et al.
Objective: The purpose of this study is to evaluate the morphology and structure of elastic arteries and find out whether there was atherosclerosis in vessels. If there were, determine the quality and thickness of the plaques, demarcate intima and media of normal and abnormal vessels and measure their thickness. In order to evaluate the values on atherosderotic diseases with IVUS, results of IVUS imaging were compare with histological examination and their correlation was calculated.
Methods: Animals (rabbits) were randomly divided into five groups. The control group was given normal diet. The other four groups were given various kinds of hypercholesterol diet respectively. Blood serum the concentration of Cho, TG, HDL, LDL, Ca2+, Glu were measured to determine whether remodelling was successful. IVUS image was performed in the successful models. After the animal anesthetized successfully, the femoral artery was dissected, punctured and a 5F sheath inserted. Heperin was given at the dose of 100 IU/kg immediately. With the help of X-ray fluoscopy, the tip of catheter was deployed on certain point of thoracic artery. Then the IVUS imaging was recorded on video- tapes. When the experiment was finished, the air was injected into vessel to kill the animal. The corresponding sites of artery which was observed by IVUS were got for histological examination. Replay the video-tapes and judged whether atherosclerosis existed. If there were plaques, the thickness was measured, the quality was determined. Some of the intima and media were demarcated and the thickness was measured. At the same time, the above index were measured or determine pathologically. Results of the two methods were compared and correlation was calculated.
Results: Comparing with pathological examination, there was no statistical significance in determining whether atherosclerosis existed with IVUS, the conform rate amounted to 94% (In control group, IVUS showed 12 sites were all normal; pathological examination also showed the 12 sites were normal; in experiment group, IVUS demonstrated that 30 out of 33 sites existed plaque, 3 sites were normal; pathological examination demonstrated that 32 out of 33 sites existed plaque or streak, 1 was normal). There was also no statistical significance in determining the fat plaque quality, the conform rate amounted to 97% (p＞0.05). For the measurement of the thickness of plaque and media, the two methods have a good correlation (r=0.885, p＜0.05 and r=0.814, p＜0.05 respectively), but for the measurement of intima, the two methods have a poor correlation (r=0.055, p＜0.05).
Conclusion: IVUS can be used to judge whether atherosclerosis (AS) exists at elastic arteries correctly, even in its very early stage of AS. It is more important that the quality and thickness of atherosclerotic plaque can determined taccuratly. he thickness of media can be measured relatively correctly. However IVUS the intimal thickness of elastic artery could be overestimated greatly.
