Hall Timothy J, Barbone Paul, Oberai Assad A, Jiang Jingfeng, Dord Jean Francois, Goenezen Sevan, Fisher Ted G
Medical Physics Department, University of Wisconsin, Madison, Wisconsin 53706.
Curr Med Imaging Rev. 2011 Nov;7(4):313-327. doi: 10.2174/157340511798038639.
We report a summary of recent developments and current status of our team's efforts to image and quantify in vivo nonlinear strain and tissue mechanical properties. Our work is guided by a focus on applications to cancer diagnosis and treatment using clinical ultrasound imaging and quasi-static tissue deformations. We review our recent developments in displacement estimation from ultrasound image sequences. We discuss cross correlation approaches, regularized optimization approaches, guided search methods, multiscale methods, and hybrid methods. Current implementations can return results of high accuracy in both axial and lateral directions at several frames per second.We compare several strain estimators. Again we see a benefit from a regularized optimization approach. We then discuss both direct and iterative methods to reconstruct tissue mechanical property distributions from measured strain and displacement fields. We review the formulation, discretization, and algorithmic considerations that come into play when attempting to infer linear and nonlinear elastic properties from strain and displacement measurements. Finally we illustrate our progress with example applications in breast disease diagnosis and tumor ablation monitoring. Our current status shows that we have demonstrated quantitative determination of nonlinear parameters in phantoms and in vivo, in the context of 2D models and data. We look forward to incorporating 3D data from 2D transducer arrays to noninvasively create calibrated 3D quantitative maps of nonlinear elastic properties of breast tissues in vivo.
我们报告了我们团队在对体内非线性应变和组织力学特性进行成像和量化方面的近期进展和现状总结。我们的工作以临床超声成像和准静态组织变形在癌症诊断和治疗中的应用为重点。我们回顾了我们在从超声图像序列估计位移方面的近期进展。我们讨论了互相关方法、正则化优化方法、引导搜索方法、多尺度方法和混合方法。当前的实现可以在每秒几帧的速度下在轴向和横向方向上返回高精度的结果。我们比较了几种应变估计器。我们再次看到正则化优化方法的优势。然后，我们讨论了从测量的应变和位移场重建组织力学特性分布的直接方法和迭代方法。我们回顾了在试图从应变和位移测量中推断线性和非线性弹性特性时所涉及的公式化、离散化和算法考虑因素。最后，我们通过乳腺疾病诊断和肿瘤消融监测的示例应用来说明我们的进展。我们目前的状况表明，在二维模型和数据的背景下，我们已经在体模和体内证明了非线性参数的定量测定。我们期待将来自二维换能器阵列的三维数据纳入其中，以无创方式创建体内乳腺组织非线性弹性特性的校准三维定量图。
