Department of Radiology, Mayo Clinic College of Medicine and Science, Rochester, MN, United States of America.
Department of Civil and Environmental Engineering, Duke University, Durham, NC, United States of America.
Phys Med Biol. 2020 Nov 24;65(22):225026. doi: 10.1088/1361-6560/abbf97.
Many of the current techniques in transient elastography, such as shear wave elastography (SWE) assume a dominant planar shear wave propagating in an infinite medium. This underlying assumption, however, can be easily violated in real scenarios in vivo, leading to image artifacts and reconstruction errors. Other approaches that are not bound to planar shear wave assumption, such solutions based on the partial differential equation, can potentially overcome the shortcomings of the conventional SWE. The main objective of this paper is to demonstrate the advantages of the modified error in constitutive equations (MECE) formulation with total variation regularization (MECE + TV) over SWE in reconstructing the elastic moduli of different tissue-mimicking phantoms. Experiments were conducted on phantoms with inclusions of well-defined shapes to study the reconstruction of specific features relevant to practical applications. We compared the performances of MECE + TV and SWE in terms of quantitative metrics to estimate reconstruction accuracy, inclusion shape recovery, edge preservation and edge sharpness, inclusion size representation, and shear elasticity and contrast accuracies. The results indicate that the MECE + TV approach outperforms SWE based on several of these metrics. It is concluded that, with further development, the proposed method may offer elastography reconstructions that are superior to SWE in clinical applications.
许多现有的瞬态弹性成像技术，如剪切波弹性成像（SWE），都假设在无限介质中传播的是主导的平面剪切波。然而，这种基本假设在体内实际情况下很容易被违反，导致图像伪影和重建误差。其他不受平面剪切波假设限制的方法，如基于偏微分方程的解决方案，可能能够克服传统 SWE 的缺点。本文的主要目的是展示基于修正本构方程误差（MECE）的正则化（MECE+TV）在重建不同组织模拟体模的弹性模量方面相对于 SWE 的优势。在具有明确定义形状的包含物的体模上进行了实验，以研究与实际应用相关的特定特征的重建。我们比较了 MECE+TV 和 SWE 在定量指标方面的性能，以估计重建准确性、包含物形状恢复、边缘保持和边缘锐度、包含物大小表示以及剪切弹性和对比度准确性。结果表明，MECE+TV 方法在多个这些指标上优于 SWE。得出的结论是，随着进一步的发展，所提出的方法可能在临床应用中提供优于 SWE 的弹性成像重建。
