Quantitative Analysis of Relationships Among Hemodynamics, Thrombus, and Abdomina

血流动力学、血栓和腹部关系的定量分析

• 批准号: 8444884
• 负责人: Seungik Baek
• 金额: $ 17.87万
• 依托单位: MICHIGAN STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-03-01 至 2015-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8444884
• 关键词: Abdomen; Abdominal Aortic Aneurysm; Aneurysm; Aorta; Area; Biomechanics; Blood Platelets; Blood flow; Cells; Clinic; Clinical Data; Clinical Management; Clinical Research; Collaborations; Complex; Computer Simulation; Computing Methodologies; Data; Development; Disease; Distal; Engineering; Functional disorder; Goals; Growth; Image; Immune; Individual; Intracranial Aneurysm; Joints; Korea; Lesion; Liquid substance; Mechanics; Methods; Michigan; Modeling; Natural History; Operative Surgical Procedures; Patients; Platelet Activation; Play; Radiology Specialty; Recording of previous events; Research; Research Personnel; Resolution; Risk; Risk Assessment; Role; Rupture; Side; South Korea; Speed; Staging; Sudden Death; Surface; Testing; Thick; Thrombus; Time; Universities; University Hospitals; X-Ray Computed Tomography; experience; follow-up; hemodynamics; human old age (65+); men; millimeter; mortality; particle; predictive modeling; public health relevance; shear stress; simulation; statistics; time use; tool

DESCRIPTION (provided by applicant): Abdominal aortic aneurysm (AAA) is the focal enlargement of the aorta in the abdomen and its rupture is the 3rd leading cause of sudden death in men older than 65 years in the US. More in-depth understanding of the pathophysiology of the disease and patient-specific risk assessment are critically important in reducing AAA- related mortality. Many researchers considered abnormal wall shear stress as a potentially important factor in aneurysm expansion and rupture risk. Most AAAs, however, develop intraluminal thrombus (ILT) layers during the progression. The role of ILT on AAA expansion is controversial and the presence of ILT increases complexity in investigating the effect of wall shear stress on AAA expansion. Recent studies also suggest that hemodynamics in the AAA plays a critical role in thrombus formation and its growth. Previous studies, however, used patient-specific models taken from only one time point and have mostly focused on studying relationships between two factors (e.g., wall shear stress vs. AAA expansion, the presence of ILT vs. AAA expansion), which haven't been successful in fully elucidating relationships between multiple factors. Therefore, the main goal of this project is to systemically study these variables, to examine multiple hypotheses on their relationships, and to possibly develop correlations among them by using longitudinal data from AAA patients. Specific aims are to i) quantify geometric parameters for ILTs and the local expansion rates of AAAs using CT images taken at multiple times, ii) perform hemodynamic simulations with the geometric model constructed from each patient and use the Lagrangian particle method for computing the shear stress experienced by platelets, and iii) examine three hypotheses on the effect of hemodynamic factors in AAAs by using the results from Aim (i) and (ii) for multiple patients and develop correlations among AAA expansion, ILT formation, and hemodynamic parameters. To advance these goals, we have already initiated collaboration with a clinical research team in South Korea and acquired longitudinal images of small AAAs from eleven patients that have been taken with 6 to 24 month intervals with high resolution CT. We will use these longitudinal patient data for developing the proposed numerical simulations and testing of hypotheses on AAA expansion and thrombus formation using multivariate statistical analysis. In our hemodynamic simulations, we will use the Lagrangian particle method to trace the history of shear stress of platelets and to assess the dynamical effects of high shear for platelet activation at the proximal side of the geometrically complex AAA. The study presented in this proposal is a joint collaborative effort between the departments of Mechanical Engineering and Statistics at Michigan State University and the Department of Radiology at Seoul National University Hospital. The proposed research would help ultimately to determine growth rules for developing better computational models of AAAs, which will become an essential tool in clinical management and surgical treatment of the disease.

描述（由申请人提供）：腹主动脉瘤（AAA）是腹部主动脉的局灶性扩大，其破裂是美国65岁以上男性突然死亡的第三大主要原因。对疾病的病理生理和患者特定风险评估的更深入了解对于降低AAA-与AAA相关的死亡率至关重要。许多研究人员认为异常的壁剪应力是动脉瘤扩张和破裂风险的潜在重要因素。然而，大多数AAA在进展过程中会产生腔内血栓（ILT）层。 ILT对AAA扩展的作用是有争议的，而ILT的存在在研究壁剪应力对AAA扩张的影响方面增加了复杂性。最近的研究还表明，AAA中的血液动力学在血栓形成及其生长中起着关键作用。然而，先前的研究使用了仅从一个时间点获取的患者特异性模型，并且主要集中于研究两个因素之间的关系（例如，壁剪应力与AAA扩展，ILT与AAA扩张的存在），这在多个因素之间完全阐明了关系。因此，该项目的主要目标是系统地 研究这些变量，以检查其关系的多种假设，并通过使用来自AAA患者的纵向数据来发展它们之间的相关性。具体目的是i）使用多次拍摄的CT图像来量化ILT的几何参数和AAA的局部膨胀速率，ii）进行血液动力学模拟，并使用每个患者构建的几何模型，并使用拉格朗日粒子方法计算降血型的剪切应力来计算血小板经历的剪切应力，并通过对三个假设进行了iii ii）的效应（ii）的效应（ii）（ii）（ii）的效果（ii）（ii）效应（iie of the）（ii）（ii）的效果（ii）（aa）（aa）（aa）（aa）的效应（（（患者并在AAA扩张，ILT形成和血液动力学参数之间发展相关。为了促进这些目标，我们已经与韩国的一个临床研究团队启动了合作，并从11名患者中获得了小型AAA的纵向图像，这些纵向以6至24个月的时间间隔（高分辨率CT）。我们将使用这些纵向患者数据来开发提出的数值模拟，并使用多元统计分析对AAA扩展和血栓形成的假设进行测试。在我们的血流动力学模拟中，我们将使用拉格朗日粒子方法来追踪血小板的剪切应力史，并评估高剪切物对血小板激活的动力学效应 在几何复杂的AAA的近端。该提案中提出的研究是密歇根州立大学机械工程和统计部门与首尔国立大学医院放射学系之间的共同合作。拟议的研究将有助于最终确定AAAS更好的计算模型的增长规则，这将成为疾病临床管理和手术治疗的重要工具。