MRI of Structure and Function in Assessing Hemodynamic Impact on AAA Evolution

结构和功能 MRI 评估血流动力学对 AAA 进化的影响

• 批准号: 8835141
• 负责人: David A Saloner
• 金额: $ 44.17万
• 依托单位: NORTHERN CALIFORNIA INSTITUTE/RES/EDU
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-04-08 至 2018-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8835141
• 关键词: Abdominal Aortic Aneurysm; Address; Affect; Age; Aneurysm; Aorta; Aortic Aneurysm; Aortic Diseases; Biochemical; Biomechanics; Blood; Blood Vessels; Blood flow; Caliber; Cardiac; Caring; Characteristics; Clinical; Community Practice; Complex; Computer Simulation; Data Reporting; Data Set; Descriptor; Diagnosis; Disease; Disease Progression; Ensure; Evolution; FDA approved; Functional Imaging; Geometry; Growth; Guidelines; Health; Image; Individual; Inflammation; Intervention; Kinetics; Liquid substance; Location; Longitudinal Studies; Magnetic Resonance Imaging; Measurement; Measures; Mediating; Methods; Modeling; Monitor; Morphology; Natural History; Operative Surgical Procedures; Outcome; Patient Monitoring; Patient observation; Patients; Phase; Physiologic pulse; Physiology; Play; Population; Prevalence; Procedures; Process; Recruitment Activity; Risk; Role; Rupture; Ruptured Aneurysm; Staging; Stents; Structure; Thrombus; Time; Uncertainty; Vascular Diseases; Velocimetries; base; cohort; hemodynamics; imaging biomarker; in vitro Model; in vivo; iron oxide; non-compliance; premature; response; shear stress; simulation; tool

DESCRIPTION (provided by applicant): Abdominal Aortic Aneurysm (AAA) is a condition with potentially devastating outcomes if the aneurysm progresses to rupture. Although the evolution of AAA is a complex process that is likely mediated by an interplay of biochemical and biomechanical factors, and despite the geometrical and structural variability of the entity itself, current clinical criteria hinge on a single parameter - the maximal lumenal diameter. Under clinical guidelines, there is a large population of individuals who harbor aneurysms that have not yet reached a size (5.5 cms) where the benefit from surgical intervention (either open surgery or endovascular stent-graft placement) exceeds the risk of the procedure. These patients are then followed with watchful waiting. It is the hypothesis of this project that hemodynamic factors play an important role in determining whether a given aneurysm will progress more rapidly than would be estimated on the basis of maximal lumenal diameter alone. The project will develop advanced MRI capabilities to measure the geometric morphology of the vascular lumen and of any intralumenal thrombus that might be present. Imaging of functional characteristics such as vascular compliance and turbulent kinetic energy will also be implemented. Similarly, advanced Computational Fluid Dynamics (CFD) simulations will be performed to simulate, on a patient-specific basis, the velocity fields in these aneurysms. The simulations will include fluid-structur interactions, non-laminar effects, and non- Newtonian terms. Consistency of these methods will be checked in cross-comparison with one another, and against experimental flow models. A cohort of patients with aneurysms in the range from 3.5 to 5.0 cms will be recruited for bi-annual imaging. Interval data sets will be co-registered with each other and changes in aneurysm morphology will be measured. These changes will then be correlated with hemodynamic descriptors calculated for that specific aneurysm. Particular care will be taken to ensure that the project is formulated to provide data reporting and guidance that is directly relevant to the clinician in community practice. It is the hypothesis of this proposal that regions of reduced wall shear stress will correlate with regions of more rapid aneurysm growth. If this is indeed demonstrated to be the case, this project will provide the tools to identify patients who, despite relatively small aneurysm size, might be rapid progressors, and conversely, cases where patients with larger aneurysms might have relatively stable conditions. That information would be important in ensuring that rapid progressors are treated before they progress to rupture, and that patients with stable aneurysms can be spared premature surgeries.

描述（由申请人提供）：腹主动脉瘤（AAA）是一种如果动脉瘤进展至破裂则具有潜在破坏性结局的疾病。虽然AAA的演变是一个复杂的过程，可能是由生物化学和生物力学因素的相互作用介导的，尽管实体本身的几何和结构可变性， 目前的临床标准取决于单个参数-最大管腔直径。根据临床指南，有大量患有动脉瘤的个体，其尺寸尚未达到手术干预（开放手术或血管内覆膜支架置入）的受益超过手术风险的尺寸（5.5 cm）。这些患者随后被观察等待。本项目的假设是，血流动力学因素在确定给定动脉瘤是否会比仅基于最大管腔直径估计的进展更快方面发挥重要作用。该项目将开发先进的MRI功能，以测量血管腔和可能存在的任何腔内血栓的几何形态。还将对血管顺应性和湍流动能等功能特性进行成像。同样，将进行高级计算流体动力学（CFD）模拟，以根据患者具体情况模拟这些动脉瘤中的速度场。模拟将包括流体-结构相互作用、非层流效应和非牛顿项。这些方法的一致性将通过相互之间的交叉比较以及与实验流动模型的对比来检查。将招募动脉瘤在3.5至5.0 cm范围内的患者队列进行每两年一次的成像。间隔数据集将相互配准，并测量动脉瘤形态的变化。然后将这些变化与针对该特定动脉瘤计算的血流动力学描述符相关联。将特别注意确保 该项目旨在提供与社区实践中的临床医生直接相关的数据报告和指导。这是该建议的假设， 剪切应力将与动脉瘤生长更快的区域相关。如果确实证明是这种情况，该项目将提供工具来识别尽管动脉瘤尺寸相对较小但可能是快速进展者的患者，相反，较大动脉瘤患者可能具有相对稳定的病情。这些信息对于确保快速进展者在破裂之前得到治疗以及稳定动脉瘤患者可以避免过早手术非常重要。