Intravascular Ultrasound Imaging in the Assessment of Atherosclerotic Plaques Rabbit Abdominal Aorta : Comparison with Histological Findings

目的：探讨兔动脉粥样硬化斑块成分与回声的相关性。材料与方法：通过插入聚乙烯管刺激高脂血症或正常血脂兔腹主动脉斑块的形成。血管内超声(30 MHz，4.5F导管)在血管内获得两层或三层图像的位置进行检查。评价斑块的血管内超声图像，并与组织学结果对照。结果：超声图像显示斑块内强(高回声)或弱(低回声)反射声束的区域。组织学研究表明，高回声区与致密的纤维细胞外基质和平滑肌细胞的增殖密切相关，而低回声区对应的病变表现为泡沫巨噬细胞或富含蛋白多糖的松散粘液细胞外基质明显积聚，并伴有平滑肌细胞的增殖。这些结果表明，血管内超声成像可以为评估动脉粥样硬化病变的组织特征提供有用的信息。

PURPOSE : To examine the correlation between the echogenicity and the components of atherosclerotic plaques in rabbit.MATERIALS AND METHOD : We have stimulated atherosclerotic plaque formation in the abdominal aortas of hyperlipidemic or normolipidemic rabbits by inserting polyethylene tubing. Intravascular ultrasound (30-MHz, 4.5 F catheter) investigation was performed at locations in the vessel where a two or three-layered images was obtained. The intravascular ultrasound images of the plaques were evaluated and compared with the histological findings.RESULS : Ultrasound images delineated areas showing strongly (hyperechoic) or weakly (hypoechoic) reflecting ultrasound beams in the plaques. Histological studies revealed that the hyperechoic areas were closely associated with a dense fibrous extracellular matrix with proliferation of smooth muscle cells, whereas the hypoechoic areas corresponded to lesions showing a marked accumulation of foamy macrophages or proteoglycan-rich loose myxoid extracellular matrix with smooth muscle cell proliferation.CONCLUSION : A good correlation between ultrasound images and histological features was observed. These results suggest that intravascular ultrasound imaging could provide useful information for assessing the tissue characteristics of atherosclerotic lesions.