Microwave Induced Thermal Imaging

微波感应热成像

• 批准号: 6966329
• 负责人: Matthew O'Donnell
• 金额: $ 22.37万
• 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 2007-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6966329
• 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，易损斑块是特别致命的，其突然破裂通常导致管腔内血栓，直接与多种临床表现如中风和急性冠状动脉综合征相关。这些易破裂的斑块通常由位于偏心增厚内膜中心部分的大的富脂核心和薄的纤维帽组成。需要可靠的非侵入性成像工具来识别这些潜在的致命斑块。 我们已经开发出一种技术，称为微波诱导热成像（MITI），图像组织的介电和热性能具有潜在的高空间和对比度分辨率。在一组合理的假设下，成像参数只是微波吸收系数（alpha）与声速对温度的导数（lambda）的乘积。一般来说，含水组织可以很容易地区分脂质的基础上λ，这可能是特别有价值的斑块组成表征和脆弱性评估。因此，我们重新命名为MITI热应变成像（TSI），以表明我们的新重点在模型中的成像参数λ。这也使我们能够探索除微波之外的其他能量输送方法，而不会降低系统性能。我们建议测试TSI的高危斑块识别外周动脉，特别是颈动脉。如果成功，它将代表一种高性能，成本效益，非侵入性替代目前的技术，如IVUS，OCT，超快计算机断层扫描（UFCT）和磁共振成像（MRI）。 该修订后的R21申请提出了一项计划，以测试TSI作为一种潜在的无创、简单和廉价的成像工具，以高空间和对比度分辨率提供动脉斑块易损性信息。因此，本报告所建议的工作的目的是详细讨论下列问题。 1.）的人。构建一个与超声成像系统完全集成的加热源，以便在常规超声扫描期间向组织等效体模和切除组织样本提供受控的能量输送。超声波和微波加热源将被调查。 2.）的情况。开发强大的脉冲序列和数据采集方案，用于控制加热并同时进行超声成像。 3.）第三章开发信号处理方法，以消除TSI数据采集期间不必要的组织运动的影响。与所有高精度散斑跟踪方法一样，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伪影。 4.）证明TSI可以在图像中将含水组织与脂质分离，类似于为磁共振成像开发的方法，但对于外周血管应用具有高空间分辨率。 5.）在切除的动脉样本上证明TSI可以识别动脉斑块内的脂质池。 这些初步实验的结果将测试TSI作为易损斑块检测的成像技术。如果它被证明是可行的，我们将开发一个RO1的建议，建立一个集成的成像系统相结合的超声与控制热源，并探讨在颈动脉和其他外周动脉的非侵入性，在体内高风险斑块识别的可能性。