Intravascular ultrasound elastography: an overview
Intravascular ultrasound elastography: an overview
复制标题
DOI：
10.1016/s0041-624x(02)00227-5
复制
发表时间：
2002-05-01
期刊：
影响因子：
4.2
通讯作者：
van der Steen, AFW
中科院分区：
文献类型：
--
作者：
de Korte, CL;van der Steen, AFW
目前认为，动脉粥样硬化病变的组成和形态比狭窄程度更重要的急性冠状动脉缺血综合征的决定因素。当病变不稳定时，它可能破裂并引起急性血栓形成反应。易破裂的斑块包含一个被薄纤维帽覆盖的大脂质池。随着厚度的减小，帽盖中的应力增大。此外，它可能被巨噬细胞浸润削弱。血管内超声弹性成像是一种评价组织局部力学性质的技术，是评价脂质池存在和识别高应力区域的理想技术。基本原理是，由机械激励引起的组织变形是其机械特性的函数。使用超声确定组织的变形。对于血管内目的，管腔内压力被用作激励力。通过对射频（rf）信号的互相关技术获得组织中的径向应变。该应变是彩色编码和绘制作为一个免费的图像IVUS echogray.Elastography在体外验证使用患病的人冠状动脉和股动脉。超声实验后，对样本进行常规组织学处理，以复染胶原蛋白、平滑肌细胞和巨噬细胞活性。Re.基于它们的应变值在弹性图中分割离子。接下来，由对弹性成像结果不知情的观察者确定主要斑块类型（纤维性、纤维脂肪性或脂肪性）。这些实验表明，三种斑块类型中的菌株是不同的（Kruskall-Wallis p <0.001）。特别是在纤维组织和脂肪组织之间，发现了高度显著的差异（Wilcoxon p <0.001）。在体内，该技术在动脉粥样硬化的尤卡坦小型猪动物模型中得到验证。高分辨率回波帧（30帧/秒）采集近端的小孔。在压力循环的这一阶段，导管运动最小。压差约为1000的机架。取5 mmHg以确定弹性图。在尤卡坦小型猪中进行的体内验证研究显示脂肪材料中的应变值较高（ANOVA p <0.001）。所有脂肪斑块的横截面通过高应变值的存在用弹性图进行识别。此外，数据是在与动物研究中测试的相同设置的经皮腔内冠状动脉成形术患者中获得的。软，纤维，钙化和支架斑块的超声数据采集近端动脉。从压力循环期间的变形中识别的软斑块的弹性图显示应变值为1%，在斑块的肩部处应变增加至2%。从超声心动图中识别的钙化物质显示00.2%的低应变值。支架斑块的弹性图显示非常低的应变值，除了两个区域：支架支柱之间和斑块肩部。总之，血管内弹性成像似乎是一个独特的工具，以确定局部力学性质的动脉粥样硬化病变，以确定纤维和脂肪组织。实验已经证明了这种技术在体内应用的可行性，（C）2002 Elsevier Science B.V.保留所有权利。
The composition and morphology of the atherosclerotic lesion are currently considered more important determinants of acute coronary ischemic syndromes than the degree of stenosis. When a lesion is unstable, it may rupture and cause an acute thrombotic reaction. A rupture prone plaque contains a large lipid pool covered by a thin fibrous cap. The stress in the cap increased with decreasing thickness. Additionally, it may be weakened by macrophage infiltration. Intravascular ultrasound elastography might be an ideal technique to assess the presence of lipid pools and identify high stress regions.Elastography is a technique to assess local mechanical properties of tissue. The underlying principle is that the deformation of tissue by a mechanical excitation is a function of its mechanical properties. The deformation of the tissue is determined using ultrasound. For intravascular purposes, the intraluminal pressure is used as the excitation force. The radial strain in the tissue is obtained by cross-correlation techniques on the radio frequency (rf) signal. The strain is colour-coded and plotted as a complimentary image to the IVUS echogram.Elastography was validated in vitro using diseased human coronary and femoral arteries. After the ultrasound experiments, the specimens were processed for routine histology to counterstain collagen, smooth-muscle cells, and macrophage activity. Re.-ions were segmented in the elastograms based on their strain values. Next, the dominant plaque type (fibrous, fibro-fatty or fatty) was defined by observers blinded to the elastographic result. These experiments demonstrate that the strain in the three plaque types is different (Kruskall-Wallis p < 0.001). Especially between fibrous and fatty tissue, a highly significant difference (Wilcoxon p < 0.001) was found,In vivo, the technique is validated in an atherosclerotic Yucatan mini-pig animal model. High-resolution echo frames (30 frames per second) were acquired near end-diastole. In this phase of the pressure cycle, catheter motion was minimal. Frames with a pressure difference of approx. 5 mmHg were taken to determine the elastograms. This in vivo validation study in Yucatan mini-pigs revealed higher strain values in fatty material (ANOVA p < 0.001). All cross-sections with a fatty plaque were identified with the elastogram by the presence of high strain values.Additionally, data are acquired in patients referred for Percutaneous Transluminal Coronary Angioplasty with the same set-up as tested in the animal study. Ultrasound data of soft, fibrous, calcified and stented plaques are acquired near end-diastole. The elastogram of soft plaques, as identified from the deformation during the pressure cycle, reveals strain values of 1% with increased strain up to 2% at the shoulders of the plaque. Calcified material, as identified from the echogram, shows low strain values of 00.2%. The elastogram of stented plaques reveals very low strain values, except for two regions: these are between the stent struts and at the shoulders of the plaque. In conclusion, intravascular elastography appears to be a unique toot to determine local mechanical properties in atherosclerotic lesions to identify fibrous and fatty tissue. Experiments have demonstrated the feasibility of this technique to be applied in vivo, (C) 2002 Elsevier Science B.V. All rights reserved.