Kheirkhah Niusha, Sadeghi-Naini Ali, Samani Abbas
Annu Int Conf IEEE Eng Med Biol Soc. 2020 Jul;2020:2055-2058. doi: 10.1109/EMBC44109.2020.9176086.
Many types of cancers are associated with changes in tissue mechanical properties. This has led to the development of elastography as a clinically viable method where tissue mechanical properties are mapped and visualized for cancer detection and staging. In quasi-static ultrasound elastography, a mechanical stimulation is applied to the tissue using ultrasound probe. Using ultrasound radiofrequency (RF) data acquired before and after the stimulation, the tissue displacement field can be estimated. Elasticity image reconstruction algorithms use this displacement data to generate images of the tissue elasticity properties. The accuracy of the generated elasticity images depends highly on the accuracy of the tissue displacement estimation. Tissue incompressibility can be used as a constraint to improve the estimation of axial and, more importantly, the lateral displacements in 2D ultrasound elastography. Especially in clinical applications, this requires accurate estimation of the out-of-plane strain. Here, we propose a method for providing an accurate estimate of the out-of-plane strain which is incorporated in the incompressibility equation to improve the axial and lateral displacements estimation before elastography image reconstruction. The method was validated using in silico and tissue mimicking phantom studies, leading to significant improvement in the estimated displacement.
许多类型的癌症都与组织力学特性的变化有关。这促使弹性成像技术得以发展，成为一种临床上可行的方法，通过绘制和可视化组织力学特性来进行癌症检测和分期。在准静态超声弹性成像中，使用超声探头对组织施加机械刺激。利用刺激前后采集的超声射频（RF）数据，可以估计组织位移场。弹性图像重建算法利用这些位移数据生成组织弹性特性图像。所生成弹性图像的准确性在很大程度上取决于组织位移估计的准确性。在二维超声弹性成像中，组织不可压缩性可作为一种约束条件，以改进轴向位移的估计，更重要的是改进横向位移的估计。特别是在临床应用中，这需要精确估计平面外应变。在此，我们提出一种方法来精确估计平面外应变，该应变被纳入不可压缩性方程，以在弹性成像图像重建之前改进轴向和横向位移估计。该方法通过计算机模拟和组织模拟体模研究进行了验证，从而使估计位移有了显著改善。
