ESTIMATION AND IMAGING OF TISSUE ELASTICITY

在本项目目前的资金期内，我们完成了以下任务。1.我们已经证明，使用略微改进的商用超声扫描仪，可以从体模和组织中产生客观质量良好的图像(弹性图)。2.已证明在正常组织成分和肿瘤中存在可靠的弹性模量差；3.阐明了产生高质量弹性图所涉及的力学、数学、统计学、声学和信号处理问题的科学基础，并计算了性能上限。已经开发了许多新的工具来改进相关参数之间的权衡。在这种更新应用中，我们的假设是，通过使用我们关于基本弹性组织属性和关于弹性成像图像形成过程的知识，可以显著改进弹性成像。为了检验这一假设，我们提出了如下具体目标。目标1至目标3旨在进一步提高弹性图的客观质量，并从中获得更多相关信息；目标4和目标5致力于增加我们对基本组织力学特性的了解，并研究成像所涉及的实际问题。目的1.在软件、体模模型和组织中对弹性纹理的理论和应用进行研究。将弹性纹理(模数和应变)与实际刚度纹理相关联。目的2.研究改善客观弹性成像图像参数的采集和信号处理策略。目的3.研究轴向和侧向组织应变、组织泊松比成像以及应用弹性图校正垂直方向运动所涉及的理论和实践问题。目的4.继续研究组织的基本弹性行为(贝勒分包)。目的5.发展一种非相干谱应变估计技术及其在噪声环境下的弹性成像中的应用。

In the present funding period of this project, we have accomplished the following tasks. 1. We have demonstrated that it is possible to produce images (elastograms) of good objective quality from phantoms and tissue sin vivo and in vitro using a slightly modified commercial ultrasound scanner. 2. It has been demonstrated that reliable elastic modulus contrast exists in normal tissue component and in tumors; 3. The scientific foundations of the mechanical, mathematical, statistical, acoustical and signal processing issues involved in the production of quality elastograms have been elucidated and upper performance bounds have been calculated. Numerous new tools have been developed to improve the tradeoffs among the relevant parameters. In this renewal application, our hypothesis is that significant improvements to elastograms may be obtained by using our knowledge about basic elastic tissue properties and about the elastographic image formation process. In order to test this hypothesis, we propose the specific aims shown below. Aims 1 through 3 are designed to further improve on the objective quality of the elastograms and to derive additional relevant information from them; aims 4 and 5 strive to increase our understanding of basic tissue mechanical properties, and to investigate the practical issues involved in imaging them. Aim 1. Investigate the theoretical and practical aspects of elastographic texture in software, phantom models and tissues. Relate elastographic texture (modulus and strain) to actual stiffness texture. Aim 2. Investigate acquisition and signal processing strategies for improving objective elastographic image parameters. Aim 3. Investigate the theoretical and practical issues involved in the imaging of axial and lateral tissue strains, tissue Poisson's ratios, and in applying corrections of elastograms for motions in orthogonal directions. Aim 4. Continue to investigate the basic elastic behavior of tissues (Baylor subcontract). Aim 5. Develop an Incoherent Spectral Strain Estimation technique and its applications to elastography in noisy environments.