IMPROVING CARDIAC IMAGING WITH NONLINEAR ULTRASOUND

利用非线性超声改善心脏成像

• 批准号: 6734721
• 负责人: JAMES Gegan MILLER
• 金额: $ 33.37万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-05-01 至 2006-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6734721
• 关键词: animal tissue; bioengineering /biomedical engineering; bioimaging /biomedical imaging; biomedical equipment development; echocardiography; heart imaging /visualization /scanning; physics

DESCRIPTION (provided by applicant): The long range objective of the proposed research is to contribute to extending and enhancing diagnostic ultrasound by elucidating the physical principles underlying the use of nonlinear imaging. Echocardiography evolved from linear (fundamental) imaging to nonlinear (harmonic) imaging in a remarkably short period of time. The instrumental advances that facilitated this rapid evolution were initially developed to capitalize on the properties of contrast agents. However, it soon became clear that the nonlinear properties of tissue alone were sufficiently strong that images could be formed at frequencies near 2-f from an ultrasonic beam transmitted at 1-f. For many patients, the resulting harmonic images are of notably higher quality than the corresponding fundamental images. The rationale that underpins our proposed research is that a better understanding of the physics responsible for the generation (with distance traveled) and the propagation of the nonlinear signals, which arise from the (linearly generated) fundamental ultrasonic field developed at the face of the imaging transducer, will lay the foundation for even more significant improvements in image quality. We propose experimental studies under laboratory conditions of nonlinear ultrasonic propagation in excised hearts and other tissues interrogated through phase-aberrating media analogous to chest or abdominal wall, and in tissue-mimicking media with well-controlled attenuation, backscatter, and speed of sound. We propose to compare the results of our measurements with predictions based on a Burgers equation enhanced, nonlinear angular spectrum simulation approach. Using the results of these experiments and simulations, we propose to evaluate the strengths and limitations of the concept of "effective apodization" to characterize the central features of the diffracting and attenuating nonlinearly generated field as it propagates in the patient. The proposed research is designed to enhance the role of ultrasound in the clinical environment by providing definitive answers to a detailed series of explicitly posed questions.

描述（由申请人提供）： 拟议研究的长期目标是通过阐明非线性成像使用的物理原理来扩展和增强超声诊断。超声心动图在非常短的时间内从线性（基本）成像发展到非线性（谐波）成像。促进这种快速发展的仪器进步最初是为了利用造影剂的特性而开发的。然而，人们很快就发现，仅组织的非线性特性就足够强，可以通过以 1-f 传输的超声波束以接近 2-f 的频率形成图像。对于许多患者来说，生成的谐波图像的质量明显高于相应的基本图像。支持我们提出的研究的基本原理是，更好地理解负责产生（随行进距离）和非线性信号传播的物理原理，这些非线性信号是由成像换能器表面产生的（线性生成的）基本超声波场产生的，将为图像质量的更显着改善奠定基础。我们建议在实验室条件下，在切除的心脏和其他组织中进行非线性超声传播的实验研究，这些组织通过类似于胸壁或腹壁的相位畸变介质以及在衰减、反向散射和声速得到良好控制的组织模拟介质中进行询问。我们建议将测量结果与基于 Burgers 方程增强的非线性角谱模拟方法的预测进行比较。利用这些实验和模拟的结果，我们建议评估“有效变迹”概念的优点和局限性，以表征在患者体内传播时衍射和衰减非线性生成场的中心特征。拟议的研究旨在通过为一系列明确提出的详细问题提供明确的答案来增强超声在临床环境中的作用。