Wang Z G, Liu Y, Wang G, Sun L Z
Department of Civil and Environmental Engineering, University of Iowa, Iowa City, IA 52242, USA.
Int J Biomed Imaging. 2009;2009:406854. doi: 10.1155/2009/406854. Epub 2009 Jul 9.
Elastography is developed as a quantitative approach to imaging linear elastic properties of tissues to detect suspicious tumors. In this paper a nonlinear elastography method is introduced for reconstruction of complex breast tissue properties. The elastic parameters are estimated by optimally minimizing the difference between the computed forces and experimental measures. A nonlinear adjoint method is derived to calculate the gradient of the objective function, which significantly enhances the numerical efficiency and stability. Simulations are conducted on a three-dimensional heterogeneous breast phantom extracting from real imaging including fatty tissue, glandular tissue, and tumors. An exponential-form of nonlinear material model is applied. The effect of noise is taken into account. Results demonstrate that the proposed nonlinear method opens the door toward nonlinear elastography and provides guidelines for future development and clinical application in breast cancer study.
弹性成像技术是作为一种对组织的线性弹性特性进行成像以检测可疑肿瘤的定量方法而发展起来的。本文介绍了一种用于重建复杂乳腺组织特性的非线性弹性成像方法。通过最优地最小化计算力与实验测量值之间的差异来估计弹性参数。推导了一种非线性伴随方法来计算目标函数的梯度，这显著提高了数值效率和稳定性。在从包括脂肪组织、腺体组织和肿瘤的真实成像中提取的三维异质乳腺模型上进行了模拟。应用了指数形式的非线性材料模型。考虑了噪声的影响。结果表明，所提出的非线性方法为非线性弹性成像打开了大门，并为乳腺癌研究中的未来发展和临床应用提供了指导。
