Super-harmonic ultrasonic imaging of the coronary artery

美国心血管疾病的增加产生了对可以进行筛查的方法的需求 对于危及生命的斑块的高危患者，评估新的心血管药物的有效性。 病变血管中血管的异常增殖可能促进血管病变的进展 并增加斑块破裂的倾向。因此，我们和其他人积极 开发可视化血管的方法。对比增强超声(CEU)成像是 常用于显示颈动脉内的血管；然而，缺乏灵敏的高 频率宽带导管阻止了研究人员将CEU推进到较小的冠状动脉。 为了克服这一技术挑战，我们计划使用光学机械转换原理来 开发高性能(灵敏和宽带)可调谐超声导管。具体地说，我们将设计 并用碳化硅制作了一种新型的高质量光机械谐振器(目标1)。这是光机 谐振器将构成我们计划开发的可调谐超声换能器的主干(目标2)。我们会 使用光机谐振器检测谐波信号(次谐波、基波、二次谐波、 超谐和超谐)，当微泡超声造影剂被激发 20 MHz压电式换能器。我们计划进行体模研究，以评估 集成光机/压电换能器。我们将使用胚胎雏鸡模型来评估 利用所提出的集成光机/压电换能器产生的谐波图像的灵敏度 以及双频传感器(一种与之竞争的技术)，以应对血管大小和密度的变化。如果成功， 这项提议的技术可以通过提供一种新的制造方法来彻底改变超声成像 几种临床应用所需的可靠宽带传感器。此外，拟议的研究 是建立血管成像作为评估疗效的技术的关键一步。 新的心血管药物。

The increase in cardiovascular disease in the United States has created a need for methods that can screen high-risk patients for life-threatening plaques and assess the effectiveness of new cardiovascular drugs. Abnormal proliferation of the vasa vasorum in diseased vessels may promote the progression of atherosclerosis and increase the propensity of plaque rupture. Consequently, we and others are actively developing methods for visualizing the vasa vasorum. Contrast-enhanced ultrasound (CEU) imaging is frequently used to visualize the vasa vasorum within the carotid artery; however, the lack of sensitive high frequency broadband catheters has prevented researchers from advancing CEU to the smaller coronary artery. To overcome this technological challenge, we plan to use the principle of optomechanical transduction to develop high-performance (sensitive and broadband) tunable ultrasound catheters. Specifically, we will design and fabricate a novel high quality optomechanical resonator from silicon carbide (Aim 1). This optomechanical resonator will form the backbone of a tunable ultrasound transducer that we plan to develop (Aim 2). We will use the optomechanical resonator to detect harmonic signals (subharmonic, fundamental, second harmonic, ultra-harmonic, and super-harmonic) emitted when microbubble ultrasound contrast agents are excited with a 20 MHz piezoelectric transducer. We plan to perform phantom studies to evaluate the performance of the integrated optomechanical/piezoelectric transducer. We will use an embryonic chick model to assess the sensitivity of harmonic images created with the proposed integrated optomechanical/piezoelectric transducer and dual frequency transducers (a competing technology) to changes in vessel size and density. If successful, the proposed technology could revolutionize ultrasonic imaging by providing a novel approach for fabricating reliable broadband transducers desired by several clinical applications. Additionally, the proposed research represents a critical step towards establishing vasa vasorum imaging as a technique for evaluating the efficacy of new cardiovascular drugs.