Non-invasive high-frequency vascular ultrasound elastography
Non-invasive high-frequency vascular ultrasound elastography
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DOI：
10.1088/0031-9155/50/7/020
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发表时间：
2005-04-07
影响因子：
3.5
通讯作者：
Cloutier, G
中科院分区：
文献类型：
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作者：
Maurice, RL;Daronat, M;Cloutier, G
非侵入性血管弹性成像（NIVE）最近被引入来表征浅表动脉的力学特性。本文对NIVE的可行性及其在高频超声成像中的适用性进行了研究。首先，在体外模拟血管的模型上进行实验。采用聚乙烯醇低温凝胶制备了两种力学性能不同的双层容器。在这两种情况下，内层的刚度都变软了。径向应力被施加在管腔内的幻影通过施加增量静压步骤与一柱流动的水-甘油混合物。用超声生物显微镜在32 MHz下对血管幻象进行超声，以提供射频（RF）超声数据的横截面序列。采用拉格朗日散斑模型估计器（LSME）对二维应变张量进行估计，计算了复合Von Mises弹性图。介绍了一种基于光流方程的LSME的新实现方法。利用反演算法估计变形参数。在每个体外实验中，两层近似为1朗姆酒。其次，介绍了该方法在转基因啮齿动物小血管研究中的应用。颈动脉纵向扫描在40mhz下进行。体内实验结果为MicroNIVE作为无创研究靶基因对啮齿动物血管重塑影响的潜在工具的可行性提供了信心。
Non-invasive vascular elastography (NIVE) was recently introduced to characterize mechanical properties of superficial arteries. In this paper, the feasibility of NIVE and its applicability in the context of high-frequency ultrasound imaging is investigated. First, experiments were performed in vitro on vessel-mimicking phantoms. Polyvinyl alcohol cryogel was used to create two double-layer vessels with different mechanical properties. In both cases, the stiffness of the inner layer was made softer. Radial stress was applied within the lumen of the phantoms by applying incremental static pressure steps with a column of a flowing mixture of water-glycerol. The vessel phantoms were insonified at 32 MHz with an ultrasound biomicroscope to provide cross-section sequences of radio-frequency (RF) ultrasound data. The Lagrangian speckle model estimator (LSME) was used to assess the two-dimensional-strain tensors, and the composite Von Mises elastograms were computed. A new implementation of the LSME based on the optical flow equations was introduced. Deformation parameters were estimated using an inversion algorithm. For each in vitro experiment, both layers of approximately I rum were distinguished. Second, the use of the method for the purpose of studying small vessels (MicroNIVE) in genetically engineered rodents was introduced. Longitudinal scans of the carotid artery were performed at 40 MHz. The in vivo results give confidence in the feasibility of MicroNIVE as a potential tool to non-invasively study the impact of targeted genes on vascular remodelling in rodents.