Mechanisms of Image Quality Improvement via Harmonic Imaging

描述（由申请人提供）：尽管谐波成像在超声中被广泛接受，但与传统超声相比，图像质量改善的机制尚未得到充分理解。在文献中已经提出了三种这样的机制，并且这些机制已经在水槽实验中得到了证明。然而，这些机制的意义仍然是模糊的在体内成像。我们假设这些机制的阐明可以导致谐波信号生成的优化，并产生进一步的图像质量改善。我们已经开发了强大的模拟工具，能够通过各种介质，包括漫散射体和分层和畸变介质在3-D传播的非线性波。这些模拟不限于向前传播的波，并且可以模拟来自漫散射站点的穆尔径反射以及来自分层和畸变介质的混响。我们还开发了体内实验技术，分别表征每种机制。我们已经开发了这些技术，用于一种新型的1728通道波束形成系统能够实时3-D成像。我们提出了一系列的实验，旨在分离和确定在体内的每个机制的贡献。使用1728通道波束形成系统在志愿者和患者的膀胱和肝脏中进行这些实验。此外，我们提出了新的模拟研究，告知我们的体内实验，能够3-D非线性波传播。基于我们的模拟和临床研究，我们提出了优化方法的谐波信号产生和第二轮的临床研究，观察优化的谐波成像方法在体内。公共卫生相关性：在本提案中，我们讨论了超声谐波成像的物理机制。关键的问题是，在对人体成像时，人们对这些机制知之甚少。我们建议扩大我们的知识，这些机制和改进谐波成像方法的基础上，这方面的知识。

DESCRIPTION (provided by applicant): Despite the widespread acceptance of harmonic imaging in ultrasound, the mechanisms by which image quality is improved over conventional ultrasonography are not well understood. Three such mechanisms have been proposed in the literature, and these mechanisms have been demonstrated in water tank experiments. However, the significance of these mechanisms remain ambiguous for in vivo imaging. We hypothesize that elucidation of these mechanisms can lead to optimization of harmonic signal generation and yield further image quality improvement. We have developed powerful simulation tools capable of propagating nonlinear waves through various media including diffuse scatterers and layered and aberrating media in 3-D. These simulations are not limited to forward propagating waves, and can model mul- tipath reflections from diffuse scattering sites and reverberations from layered and aberrating media. We have also developed in vivo experimental techniques for characterizing each mechanism individually. We have developed these techniques to be used on a novel 1728 channel beamforming system capable of real-time 3-D imaging. We propose a series of experiments designed to separate and determine the contribution of each mechanism in vivo. These experiments are performed in the bladders and livers of volunteers and patients using the 1728 channel beamforming system. In addition, we propose novel simulation studies, informed by our in vivo experimentation, that are capable of 3-D nonlinear wave propagation. Based on our simulations and clinical studies, we propose optimization methods of harmonic signal generation and a second round of clinical studies to observe the optimized harmonic imaging methods in vivo. PUBLIC HEALTH RELEVANCE: In this proposal, we address the physical mechanisms of harmonic imaging in ultrasound. The key problem is that these mechanisms are poorly understood when imaging the human body. We propose to expand our knowledge of these mechanisms and improve harmonic imaging methods based on this knowledge.