Nonlinear response of encapsulated contrast microbubbles for noninvasive blood pressure measurement

CBET -1603639 PI：Sarkar，KausikMicrobubbles常规用于医学诊断，以增强超声图像的对比度。 微泡通常被脂质或蛋白质包裹，以便它们在引入血流时持续存在。 该项目的假设是，血流中封装的微泡的声学响应可以与周围组织的声学响应分离，并可用于测量各种器官的小血管中的血压。 该项目包括实验，以测量封装的微泡在不同的环境压力下的声学响应，一个数值模型的发展，以帮助解释实验数据，并制定一个协议的压力估计，将与医生在托马斯杰斐逊大学谁发现封装的微泡的声学响应取决于当地的压力进行测试。 这项研究的结果可以为医生提供一种新的诊断工具来测量整个身体的血压，从而能够早期发现特定器官的疾病。 调查人员将参与该项目的学生在所有的学术水平，包括本科生从群体传统上代表不足的科学和工程。这一建议建立在一个观察所作的临床医生在托马斯杰斐逊大学的次谐波反应，从对比微泡减少与环境压力的增加。然而，其他实验，包括项目研究人员的实验和研究人员开发的模型表明，次谐波响应可能会随着环境压力的增加或减少。 该项目的目标是解释明显的差异，描绘不同行为的区域，并确定次谐波响应如何取决于封装微泡的压力依赖性机械性能。 在与托马斯杰斐逊医学医院的临床医生合作，研究人员将合成脂质涂层微泡，并在不同的环境压力下使用非线性界面流变模型表征其膨胀，研究对比微泡的压力依赖性非线性响应，并确定最佳材料和激励参数用于压力估计。

CBET - 1603639PI: Sarkar, KausikMicrobubbles are used routinely in medical diagnostics to enhance the contrast of ultrasound images. The microbubbles usually are encapsulated with lipids or proteins so that they persist when introduced into the blood stream. The hypothesis of this project is that the acoustic response of encapsulated microbubbles in the bloodstream can be separated from the acoustic response of surrounding tissue and can be used to measure the blood pressure in the small blood vessels of various organs. The project comprises experiments to measure the acoustic response of encapsulated microbubbles under varying ambient pressures, the development of a numerical model to help interpret the experimental data, and the formulation of a protocol for pressure estimation that will be tested in collaboration with physicians at Thomas Jefferson University who discovered that the acoustic response of encapsulated microbubbles depends on the local pressure. Results of the study could provide physicians with a new diagnostic tool to measure blood pressure throughout the body to enable early detection of disease in specific organs. The investigators will involve in the project students at all academic levels, including undergraduates from groups traditionally underrepresented in science and engineering.This proposal builds on an observation made by clinicians at the Thomas Jefferson University that the subharmonic response from contrast microbubbles decreases with increasing ambient pressure. However, other experiments, including those by the project investigators, and models developed by the investigators suggest the subharmonic response may increase or decrease with ambient pressure. The goal of the project is to explain the apparent discrepancy, delineate regions of different behaviors, and determine how the subharmonic response depends on the pressure-dependent mechanical properties of encapsulated microbubbles. In collaboration with clinicians at Thomas Jefferson Medical Hospital, the investigators will synthesize lipid coated microbubbles and characterize their encapsulations using a nonlinear interfacial rheological model at different ambient pressures, investigate the pressure dependent nonlinear response from contrast microbubbles, and determine optimal material and excitation parameters for pressure estimation.