Advanced MRI Evaluation of Abdominal Aortic Aneurysms

腹主动脉瘤的高级 MRI 评估

• 批准号: 10013669
• 负责人: Michael Douglas Hope
• 金额: --
• 依托单位: VETERANS AFFAIRS MED CTR SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-10-01 至 2024-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10013669
• 关键词: 3-Dimensional; Abdominal Aortic Aneurysm; Affect; Aging; Anatomy; Aneurysm; Aortic Diseases; Biomechanics; Blood Vessels; Blood flow; Caliber; Central Artery; Cessation of life; Clinical; Computer Models; Data; Descriptor; Dimensions; Disease; Disease Progression; Early Intervention; Evaluation; Functional Imaging; Future; Goals; Growth; Hematological Disease; Image; Image Analysis; Imaging Techniques; Inflammation; Inflammatory; Intervention; Lead; Life; Magnetic Resonance Imaging; Measurement; Mechanics; Morphology; Motivation; Operative Surgical Procedures; Outcome; Pathologic; Patients; Pattern; Phase; Process; Protocols documentation; Regimen; Reporting; Resolution; Resources; Risk; Risk Assessment; Role; Rupture; Ruptured Abdominal Aortic Aneurysm; Series; Stress; Stretching; Structure; Time; Ultrasonography; Vascular Diseases; Veterans; anatomic imaging; base; biomechanical model; contrast enhanced; data modeling; experience; hemodynamics; improved; improved outcome; innovation; male; military veteran; older men; patient stratification; rapid growth; risk stratification; screening; screening program; shear stress; surveillance imaging

Abdominal aortic aneurysms (AAA) are common and can be life-threatening if they progress to rupture. They have been reported in up to 8% of older men and account for over 15,000 deaths per year. Basic vessel dimensions are currently the primary imaging measurement used clinically to risk-stratify patients. But there is more to the story than dimensions. Wall stress estimated with computational biomechanical modeling may better predict growth and rupture than diameters. Furthermore, AAA growth is often not continuous, and instead marked by periods of rapid growth followed by quiescence. Small series report that unrelated surgical procedures can precipitate AAA rupture, suggesting that episodic and heterogeneous inflammatory processes in concert with adverse hemodynamics and biomechanics are important for the progression of AAA disease. The complexity of aortic disease is more fully revealed with new functional imaging techniques than with conventional anatomic analysis alone. While AAA has been extensively studied, the mechanisms of disease progression have not been fully elucidated. If better understood, they could lead to significant improvement of the management of veterans with small AAAs (< 5.5 cm). Many of these aneurysms can be followed safely with a long screening interval of 2-3 years, but some may progress to rupture. Identifying this subset would greatly streamline the surveillance imaging of veterans with AAA. On the other hand, the majority of AAAs never rupture, and identifying low risk veterans could help better manage resources and subject only those veterans at truly elevated risk to intervention. MRI uniquely offers comprehensive assessment of forces acting on the vessel wall (hemodynamics and biomechanics), as well as factors affecting wall strength (structure, morphology and inflammation). Blood flow imaging with time-resolved 3D phase-contrast MRI (4D Flow) allows quantification of key parameters including flow turbulence and wall shear stress. Dynamic contrast enhanced (DCE) MRI may offer efficient evaluation of aortic wall inflammation. Cine Displacement Encoding with Stimulated Echoes (DENSE) MRI can quantify regional stretch differences experienced by the vessel wall, and, in tandem with 3D volumetric MRI anatomic data and computational modeling can be used to calculate patient-specific mechanical wall stress. The aim of our study is to uncover important inflammatory changes and adverse hemodynamics and biomechanics that are not addressed by current imaging, and use them to predict AAA disease progression. We also seek to optimize a short (5 minute) MRI protocol without contrast to determine if there is added value to this comprehensive assessment, as fast non-contrast MRI would be preferable and more efficiently use VA resources. Our overall goal is to meaningfully advance the assessment of risk in veterans who do not meet current intervention thresholds and thereby in the future improve outcomes by refining surveillance imaging regimens and decisions regarding early intervention for AAAs.

腹主动脉瘤（AAA）很常见，如果它们发展到破裂，可能会危及生命。他们 据报道，多达8％的老年男性据报道，每年占15,000多人的死亡。基本船只 尺寸是目前用于临床上用于风险分解患者的主要成像测量。但是有 故事比维度更重要。用计算生物力学建模估计的壁应力可能 比直径更好地预测生长和破裂。此外，AAA的增长通常不是连续的，并且 取而代之的是以快速生长的周期和静止。小型报告无关手术 程序可能会沉淀AAA破裂，表明发作性和异质性炎症过程 与不良血液动力学和生物力学的一致性对于AAA疾病的发展很重要。 与新功能成像技术相比，主动脉疾病的复杂性比 仅常规解剖分析。虽然AAA经过广泛研究，但疾病的机制 进展尚未完全阐明。如果更好地理解，它们可能会大大改善 小型AAA（<5.5厘米）的退伍军人的管理。这些动脉瘤中的许多可以安全遵循 长时间的筛查间隔为2 - 3年，但有些可能会破裂。识别此子集将 极大地简化了用AAA对退伍军人的监视成像。另一方面，大多数AAAS 切勿破裂，识别低风险退伍军人可以帮助更好地管理资源，而仅对这些资源进行管理 退伍军人真正提高了干预风险。 MRI独特地提供了作用在血管壁上的力的全面评估（血液动力学和 生物力学）以及影响壁强度（结构，形态和炎症）的因素。血流（量 使用时间分辨的3D相对比MRI（4D流）进行成像允许量化关键参数 流湍流和壁剪应力。动态对比增强（DCE）MRI可能会对 主动脉壁发炎。用刺激的回声（密度）MRI编码的Cine位移可以量化 容器壁经历的区域拉伸差异，并与3D体积MRI解剖结合 数据和计算建模可用于计算患者特定的机械壁应力。 我们研究的目的是发现重要的炎症性变化和不良血液动力学以及 当前成像未解决的生物力学，并使用它们来预测AAA疾病进展。 我们还寻求优化一个短（5分钟）MRI协议，而不对比度确定是否有附加值 对于这项全面评估，因为快速的非对比度MRI是可取的，并且更有效地使用VA 资源。我们的总体目标是有意义地推进不遇见的退伍军人的风险评估 当前的干预阈值，从而通过完善监视成像来改善结果 有关AAAS早期干预的方案和决定。