SGER: Dynamics of Encapsulated Microbubbles for Medical Ultrasound

摘要CTS-0352829 K。Sarkar，特拉华大学微泡通过静脉注射进入患者体内，以增强超声图像的对比度。 我们的目标是开发一个可靠的数学模型，这些微泡造影剂和表征不同的代理商与it. Specifically重点的建模是保护封装的脂质，蛋白质或表面活性剂制成的对比微泡。尽管游离的微泡（没有封装）在反射超声和增强图像对比度方面表现得更好，但它们在几秒钟内就会溶解在血流中。 封装使它们稳定，从而使对比成像成为可能。 技术优点：将开发一种新的具有表面流变特性的封装界面模型。这些特性将通过使用临床批准的造影剂Detril和Optison进行的体外衰减实验来确定。我们认为，所提出的吸收界面模型包含了基本的物理性质，并且在更宽的频率和振幅范围内仍然有效。 我们将通过比较模型预测与散射实验（不同于用于模型确定的实验）来检验这一假设。 模型参数将使用适合于具有较小能量的脉冲的实验的模型的线性化版本确定。然而，发达国家的非线性动力学模型将与实测谐波和次谐波排放量进行比较。 我们的初步建模与实验数据在文献中的Optison显示令人鼓舞的协议与测量的次谐波发射。我们正在与托马斯杰斐逊医学院和医院放射科的Flemming Forsberg教授和巴里戈德堡医学博士合作进行我们研究的临床实施。除了造影超声，拟议的研究将提供关键的胶体和悬浮液中的界面动力学的理解。 更广泛的影响：超声检查是最安全和最常用的成像手段（世界上每三项成像研究中就有一项是超声检查）。 然而，由于对比度差，超声图像的实用性受到限制。 例如，2000年在美国进行的1700万次超声心动图检查中，有20%是次优的，即不能提供冠心病的明确诊断。良好的造影剂将能够对异常血流进行可靠的成像，从而导致早期可靠的诊断。造影剂的使用不限于心脏;它还包括成像肾脏、肝脏和大脑。 有效的造影剂和有效的方式的发展只能通过体外研究与临床合作，如这里提出的。拟定的表征将用于为试剂开发商（例如，阿默舍姆Health、布里斯托Myers Squibb）和扫描仪制造商（例如，GE）提供有用的指南。 这项研究将涉及工程研究生和本科生在一个非传统的跨学科的医学成像科学。

AbstractCTS-0352829K. Sarkar, University of DelawareMicrobubbles are intravenously introduced into a patient's body to enhance the contrast of an ultrasound image. Our aim is to develop a reliable mathematical model for these microbubble contrast agents and characterize different agents with it. Specifically the focus of the modeling is the protective encapsulation of a contrast microbubble made of lipids, proteins or surfactants. Even though free microbubbles (without encapsulation) perform much better in reflecting ultrasound and enhancing image contrast, they issolve in blood stream in few seconds. The encapsulation stabilizes them making contrast imaging possible. Technical merit: A new interface model for the encapsulation with surface rheological properties will be developed. These properties will be determined by in vitro attenuation experiments with clinically approved contrast agents Definity and Optison. We claim that the proposed model of absorbed interface contains the essential physics, and will remain valid over a wider range of frequency and amplitude. We will test this hypothesis by comparing model predictions with scattering experiments (different from those used for model determination). The model parameters will be determined using a linearized version of the model appropriate for experiments with pulses of less energy. However, the developed models nonlinear dynamics will be compared with measured harmonic and subharmonic emissions. Our preliminary modeling with experimental data available in the literature for Optison shows encouraging agreement with measured subharmonic emission. We are collaborating on the clinical implementation of our research with Professors Flemming Forsberg and Barry Goldberg, MD of the Radiology Department at Thomas Jefferson Medical College and Hospital. Beyond contrast ultrasound the proposed research will provide critical understanding of interface dynamics in colloids and suspensions. Broader Impact: Ultrasound examination is the safest and the most popular means of imaging (one in every three imaging studies performed in the world is an ultrasound test). Utility of ultrasonography images however is limited due to poor contrast. For instance, 20 percent of the 17 million echocardiography performed in the United States in 2000 were suboptimal, i.e. did not provide definitive diagnosis for coronary heart disease. A good contrast agent will enable reliable imaging of abnormal blood flows leading to early reliable diagnosis. Use of contrast agent is not limited to heart; it also includes imaging kidney, liver and brain. Development of effective contrast agents and efficient modality can only be achieved through in vitro research with clinical collaboration such as proposed here. The proposed characterization will be used to provide useful guidelines to agent developers (e.g. Amersham Health, Bristol Myers Squibb) and scanner manufacturers (e.g. GE). The research will involve engineering graduate and undergraduate students in a non-traditional cross-disciplinary science of medical imaging.