Cardiovascular Effects of Ultrasound and Contrast Agents

描述(由申请人提供)：本项目的总体目标是 更深入地了解超声波与 含有气基超声造影剂的心血管组织。这个 超声造影剂在诊断成像中的作用越来越大。 然而，对含有造影剂的各种组织进行超声波照射可以 对血管产生损伤。此外，一个单一的超声波脉冲就可以产生 对心脏功能的影响，例如早搏的产生 收缩和对心脏收缩能力的影响。对比度的存在 血液中的药物可以降低心脏早搏的阈值 收缩，使诊断设备的当前输出电平能够 才能产生效果。拟议的项目重点是调查 超声和造影剂对心功能和血管的影响 损坏。提出了一种综合运用这两种实验研究的方法。 和理论模型。四个相互关联的具体目标指导着 调查。首先，研究超声波对人体的生物影响 将对含有造影剂的心血管组织进行检查。以下项目的阈值 对心脏功能和血管损伤的影响将被确定为一种功能 声学和生物参数。第二，从理论上理解 超声对心血管组织中造影剂的影响 将会被开发出来。拟议工作的一个广泛目标是制定更好的 对体内声空化的认识。技术将发展到 造影剂相关条件下的声空化模型 包含在体内的血管系统中。第三，生物物理机制 将确定哪些造影剂可以增强生物效应。这是假设的 超声诱发的早搏是由声空化引起的 辐射力对收缩性能的影响。关于船舶的研究 损害将通过测试两个相互竞争的假设来引导；即超声波 对血管的诱导损伤包含1)现象的对比结果 与微泡的惯性坍塌有关和/或2)初始 微泡的膨胀阶段。第四，超声波在治疗中的应用 将对心血管组织进行调查。超声波的潜在用途 和造影剂用于无创心脏起搏、除颤和 电生理学程序将进行测试。该项目的成果将 提供安全建议所需的信息，将增加 活体声空化的知识库，并将确定 超声和造影剂潜在新应用的可行性 在医学上。

Description (provided by applicant): The overall goal of this project is to develop a greater understanding of the interaction of ultrasound with cardiovascular tissues containing gas-based ultrasound contrast agents. The role of ultrasound contrast agents in diagnostic imaging is increasing. However, ultrasound exposure of various tissues containing contrast agents can produce damage to blood vessels. Also, a single pulse of ultrasound can produce effects on cardiac function, such as the production of a premature cardiac contraction and effects on cardiac contractility. The presence of contrast agents in the blood can reduce the threshold for premature cardiac contractions, such that current output levels of diagnostic devices are capable of producing the effect. The proposed project is focused on investigating the effects of ultrasound and contrast agents on cardiac function and vascular damage. An integrated approach is proposed employing both experimental studies and theoretical modeling. Four inter-related specific aims guide the investigations. First, studies to characterize the bioffects of ultrasound on cardiovascular tissues containing contrast will be performed. Thresholds for effects on cardiac function and vessel damage will be determined as a function of acoustic and biological parameters. Second, a theoretical understanding of the response of contrast agents in cardiovascular tissues exposed to ultrasound will be developed. A broad goal of the proposed work is to develop a better understanding of acoustic cavitation in vivo. Techniques will be developed to model acoustic cavitation under conditions relevant to contrast agents contained within the vasculature in vivo. Third, the biophysical mechanisms by which contrast agents enhance bioeffects will be determined. It is hypothesized that ultrasound-induced premature contractions arise from acoustic cavitation and effects on contractility result from radiation force. Studies of vessel damage will be guided by testing two competing hypotheses; that ultrasound induced-damage to blood vessels contain contrast results from 1) phenomena associated with inertial collapse of microbubbles and/or 2) the initial expansion phase of the microbubbles. Fourth, therapeutic uses of ultrasound in cardiovascular tissues will be investigated. The potential use of ultrasound and contrast agents for noninvasive cardiac pacing, defibrillation and electrophysiology procedures will be tested. Results of this project will provide information needed for safety recommendations, will increase the knowledge base of acoustic cavitation in vivo, and will determine the feasibility of potentially new applications of ultrasound and contrast agents in medicine.