Microwave Induced Thermal Imaging

微波感应热成像

• 批准号: 7140413
• 负责人: KANG KIM
• 金额: $ 17.98万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-05 至 2008-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7140413
• 关键词: atherosclerotic plaque; bioengineering /biomedical engineering; biomedical equipment development; cardiovascular disorder diagnosis; cardiovascular imaging /visualization; clinical biomedical equipment; microwave radiation; noninvasive diagnosis; phantom model

DESCRIPTION (provided by applicant): Among all atherosclerotic lesions, vulnerable plaque is particularly lethal and its sudden rupture typically leads to intraluminal thrombus, directly linked to a variety of clinical manifestations such as stroke and acute coronary syndromes. These rupture-prone plaques usually consist of a large lipid-rich core in the central portion of the eccentrically thickened intima and a thin fibrous cap. Reliable, noninvasive imaging tools are needed to identify these potentially fatal plaques before their disruption. We have developed a technique, called microwave-induced thermal imaging (MITI), to image tissue dielectric and thermal properties with potentially high spatial and contrast resolution. Under a reasonable set of assumptions, the imaging parameter is simply the product of the microwave absorption coefficient (alpha) with the derivative of the sound speed with respect to temperature (lambda). Generally, water-bearing tissue can be easily distinguished from lipids based on lambda, which can be particularly valuable in plaque composition characterization and vulnerability assessment. Consequently, we rename MITI thermal strain imaging (TSI) to indicate our new focus on the imaging parameter lambda in the model. This also allows us to explore other energy delivery methods in addition to microwaves without degrading system performance. We propose to test TSI for high-risk plaque identification in peripheral arteries, especially the carotid. If successful, it will represent a high performance, cost-effective, noninvasive alternative to current techniques such as IVUS, OCT, ultrafast computed tomography (UFCT) and magnetic resonance imaging (MRI). This revised R21 application presents a plan to test TSI as a potentially noninvasive, simple, and cheap imaging tool providing information about arterial plaque vulnerability with high spatial and contrast resolution. It is the aim, therefore, of the work proposed here to address the following issues in detail. 1.) Construct a heating source fully integrated with an ultrasound imaging system to provide controlled energy delivery to tissue equivalent phantoms and excised tissue samples during routine ultrasound scanning. Both ultrasound and microwave heating sources will be investigated. 2.) Develop robust pulse sequence and data acquisition schemes for controlled heating with simultaneous ultrasonic imaging. 3.) Develop signal processing methods to remove the effects of unwanted tissue motion during TSI data acquisition. Like all high precision speckle tracking methods, TSI is susceptible to tissue motion artifacts. Methods must be developed to identify and minimize these artifacts. 4.) Demonstrate that TSI can separate water-bearing tissues from lipids in images similar to methods developed for magnetic resonance imaging but with high spatial resolution for peripheral vascular applications. 5.) Demonstrate on excised arterial samples that TSI can identify the lipid pool within an arterial plaque. The results of these preliminary experiments will test TSI as an imaging technique for vulnerable plaque detection. If it proves viable, we will develop an RO1 proposal to build an integrated imaging system combining ultrasound with a controlled heat source and explore the possibility of noninvasive, in vivo highrisk plaque identification in the carotid and other peripheral arteries.

描述（由申请人提供）： 在所有动脉粥样硬化病变中，脆弱的斑块尤其是致命的，其突然破裂通常会导致腔内血栓，直接与各种临床表现（例如中风和急性冠状动脉综合征）有关。这些容易发生的斑块通常由偏心增厚的内膜中央部分的大脂质核心和薄纤维帽组成。需要可靠的无创成像工具来识别这些潜在的致命斑块。 我们已经开发了一种称为微波炉诱导的热成像（MITI）的技术，用于对组织介电和热特性进行图像具有潜在的空间和对比度分辨率的技术。在合理的假设集中，成像参数仅仅是微波吸收系数（Alpha）的乘积，而音速相对于温度（LAMBDA）。通常，含水组织可以很容易地与基于Lambda的脂质区分开，这在斑块组成的表征和脆弱性评估中​​可能特别有价值。因此，我们重命名MITI热应变成像（TSI），以表明我们对模型中成像参数lambda的新关注。这也使我们能够探索除了微波的不降低系统性能的情况下，还可以探索其他能源输送方法。我们建议在周围动脉，尤其是颈动脉中测试TSI的高风险斑块鉴定。如果成功，它将代表高性能，具有成本效益的无创替代方法，例如IVU，OCT，超快计算机断层扫描（UFCT）和磁共振成像（MRI）。 该修订后的R21应用程序介绍了一项计划，将TSI作为一种潜在的无创，简单和廉价的成像工具，提供有关动脉斑块脆弱性的信息，并具有高空间和对比度分辨率。因此，这里提出的工作旨在详细解决以下问题的目的。 1.）在常规超声扫描过程中，构建与超声成像系统完全集成的加热源，以向组织等效幻象和切除的组织样品提供控制能量输送。将研究超声和微波加热来源。 2.）开发可通过超声成像的同时加热的强大脉冲序列和数据采集方案。 3.）开发信号处理方法，以消除TSI数据采集期间不需要的组织运动的影响。像所有高精度斑点跟踪方法一样，TSI易受组织运动伪影的影响。必须开发方法来识别和最小化这些工件。 4.）证明TSI可以在类似于用于磁共振成像的方法的图像中将含水组织与脂质分开，但具有高空间分辨率用于外周血管应用。 5.）在切除的动脉样品上证明TSI可以鉴定动脉斑块中的脂质池。 这些初步实验的结果将测试TSI作为脆弱斑块检测的成像技术。如果证明这是可行的，我们将开发一个RO1提案，以建立一个集成的成像系统，结合了超声和受控的热源，并探索在颈动脉和其他外围动脉中的体内高速斑块鉴定无创的可能性。