IMPROVING CARDIAC IMAGING WITH NONLINEAR ULTRASOUND

利用非线性超声改善心脏成像

• 批准号: 6594853
• 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/6594853
• 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）： 拟议研究的远距离目标是通过阐明使用非线性成像的物理原理来促进和增强诊断超声。超声心动图从线性（基本）成像演变为在短时间内的非线性（谐波）成像。最初开发了促进这种快速进化的工具进步，以利用造影剂的性质。但是，很快就很清楚，仅组织的非线性特性就足够强，可以从1-F传播的超声梁的2-F频率下形成图像。对于许多患者而言，所产生的谐波图像的质量明显高于相应的基本图像。我们提出的研究基础的理由是，对负责生成的物理学（随距离行进）和非线性信号的繁殖是从成像转换器面对面开发的（线性生成的）基本超声波磁场引起的非线性信号的传播，这将为图像质量提供更大的改进。我们在非线性超声传播的实验室条件下提出了实验研究，在切除的心脏和其他组织中，通过相似于胸部或腹壁类似的相结合的培养基，以及具有良好控制的介质，具有良好的衰减，反向散射和声音速度。我们建议将测量结果与基于汉堡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“有效伪造”概念的优势和局限性，以表征患者在患者中传播的衍射和衰减非线性生成的领域的主要特征。拟议的研究旨在通过为一系列明确提出的问题提供明确的答案来增强超声在临床环境中的作用。