Photoacoustics & Ultrasound Laboratory Eindhoven (PULS/e), Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, the Netherlands.
Photoacoustics & Ultrasound Laboratory Eindhoven (PULS/e), Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, the Netherlands.
J Mech Behav Biomed Mater. 2021 Jul;119:104509. doi: 10.1016/j.jmbbm.2021.104509. Epub 2021 Apr 14.
Mechanical characterization of abdominal aortic aneurysms using personalized biomechanical models is being widely investigated as an alternative criterion to assess risk of rupture. These methods rely on accurate wall motion detection and appropriate model boundary conditions. In this study, multi-perspective ultrasound is combined with finite element models to perform mechanical characterization of abdominal aortas in volunteers. Multi-perspective biplane radio frequency ultrasound recordings were made under seven angles (-45° to 45°) in one phantom set-up and eight volunteers, which were merged using automatic image registration. 2-D displacement fields were estimated in the seven longitudinal ultrasound views, creating a sparse, high resolution 3-D map of the wall motion at relatively high frame rates (20-27 Hz). The displacements were used to personalize the subject-specific finite element model of which the geometry of the aorta, spine, and surrounding tissue were determined from a single 3-D ultrasound acquisition. Automatic registration of the multi-perspective images was successful in six out of eight cases with an average error of 5.4° compared to the ground truth. Displacements of the aortic wall were measured and cyclic strain of the aortic diameter was found ranging from 4.2% to 8.6%. The subject-specific mesh and inverse FE analysis was performed yielding shear moduli estimates for the wall between 104 and 215 kPa. Comparative results from a single-perspective workflow revealed very low aortic wall motion signal, which resulted in relatively high modulus estimates, between 230 and 754 kPa. Multi-perspective biplane ultrasound imaging was used to personalize finite element models of the abdominal aorta and its surroundings, and performing mechanical characterization of the aortic shear modulus. The method was found to be a more robust method compared to a single-perspective 3-D ultrasound approach. Future research will focus on investigating the use of multiple 3-D ultrasound acquisitions, the feasibility of free-hand scanning, the creation of a full 3-D automatic registration process, and with that, enable a clinical continuation of this study.
使用个性化生物力学模型对腹主动脉瘤进行力学特性分析正被广泛研究，作为评估破裂风险的替代标准。这些方法依赖于精确的壁运动检测和适当的模型边界条件。在这项研究中，多视角超声与有限元模型相结合，对志愿者的腹主动脉进行力学特性分析。在一个体模设置和八个志愿者中进行了七种角度（-45°至 45°）的多视角双平面射频超声记录，使用自动图像配准进行了合并。在七个纵向超声视图中估计了 2-D 位移场，以相对较高的帧率（20-27 Hz）创建了壁运动的稀疏、高分辨率 3-D 图谱。这些位移被用于个性化受试者特定的有限元模型，该模型的主动脉、脊柱和周围组织的几何形状是从单次 3-D 超声采集中确定的。六个案例中的多视角图像自动配准成功，与真实值相比，平均误差为 5.4°。测量了主动脉壁的位移，并发现主动脉直径的循环应变范围在 4.2%至 8.6%之间。进行了个性化网格和逆有限元分析，得出了壁的剪切模量估计值在 104 至 215 kPa 之间。来自单视角工作流程的比较结果显示，主动脉壁运动信号非常低，导致相对较高的模量估计值，在 230 至 754 kPa 之间。使用多视角双平面超声成像来个性化腹主动脉及其周围环境的有限元模型，并对主动脉剪切模量进行力学特性分析。与单视角 3-D 超声方法相比，该方法被证明是一种更稳健的方法。未来的研究将集中于调查使用多个 3-D 超声采集、徒手扫描的可行性、创建完整的 3-D 自动配准过程，以及在此基础上，使这项研究能够在临床上继续进行。
