4D Flow Cardiac Magnetic Resonance FOR Post Myocardial Infarction left ventricular thrombus

项目总结/摘要 左心室血栓（LVT）为栓塞事件提供了基础，也是抗凝治疗的依据。去- 尽管在冠状动脉再灌注方面取得了进展，但ST段抬高型心肌梗死（MI）后LVT仍然很常见， 发生于多达1/5的累及LV心尖部的MI患者。LVT的预测因素是有限的，如以下所示： 数据显示，超过一半的病例发生时没有明显的整体LV功能障碍或动脉瘤。不确定谁会 发生LVT可能解释了临床数据显示抗凝治疗增加出血而不减少 在看似有风险的MI后人群中发生卒中。考虑到LVT引起的卒中和出血的严重性， 它的治疗，提高对LVT的理解是非常重要的， 美国ST段抬高型心肌梗死的患者。心脏磁共振（CMR）成像提供了一个高度 然而，目前的方法仅限于预测谁将发生LVT。本研究 基于LVT形成源于LV血流改变及其决定因素的假设。到 为了验证这一点，LV血流将通过体积时间分辨的“4D流动MRI”进行量化，这是一种新的方法， 测量体内时间分辨的体积速度矢量。我们将开发一种新的成像方法， 准确评估MI背景下的LV血流损害。Aim 1将开发新的MRI方法， 可广泛应用于量化左心室停滞（低速）。具体而言，目标4D流动MRI脉冲 将开发一个序列（通过径向星叠采集和双速度编码），以实现定向 对低流速敏感的LV血流评估。目标2将验证新方法：新目标 采集将与传统的全胸部采集进行比较，以获得与参考标准的相似性（通过 体外光学成像）或用于体内可重复性。目标3将在MI患者的试点队列中测试LV血流指数 评价MI后心尖部淤滞（局部血流速度、动能、残余血容量）是否 与LVT有关。项目发起人和合作者在成功翻译CMR方面有着良好的记录 研究和MRI物理学，独特的资格，他们对拟议的工作导师。新的信息， 通过更精确地识别MI后血流， 与LVT相关的模式，从而建立未来的试验来测试这些参数作为LVT的预测因子。的 PI在该项目中获得的技能将使他成为成功的独立研究生涯的有力人选 心血管核磁共振成像

Project Summary/Abstract Left ventricular thrombus (LVT) provides a substrate for embolic events and a rationale for anticoagulation. De- spite advances in coronary reperfusion, LVT remains common after ST elevation myocardial infarction (MI)– occurring in up to 1 in 5 patients with MI involving the LV apex. Predictors of LVT are limited, as evidenced by data that over half of cases occur without marked global LV dysfunction or aneurysm. Uncertainty as to who will develop LVT may explain clinical data that have shown anticoagulation to increase bleeding without decreasing stroke in seemingly at risk post-MI groups. Given the seriousness of stroke and bleeding conferred by LVT and its treatment, improved understanding of LVT is of major importance for the over quarter million people in the U.S. who sustain ST elevation MI each year. Cardiac magnetic resonance (CMR) imaging provides a highly accurate means to identify LVT, but current approaches are limited to predict in whom LVT will occur. This study is predicated on the hypothesis that LVT formation stems from altered LV blood flow and its determinants. To test this, LV blood flow will be quantified via volumetric time resolved “4D flow MRI” - a new method that can measure time-resolved, volumetric velocity vectors in vivo. We will develop a novel imaging approach for accurate assessment of LV flow impairment in in the context of MI. Aim 1 will develop new MRI methods that can be widely applied to quantify left ventricular stasis (low velocities). Specifically, a targeted 4D flow MRI pulse sequence (via radial stack-of-stars acquisition and dual velocity encoding) will be developed to achieve directed flow assessment of the LV with sensitivity to low velocities. Aim 2 will validate the new method: the new targeted acquisition will be compared with conventional full-chest acquisition for similarity to a reference standard (via optical imaging in vitro) or for repeatability in vivo. Aim 3 will test LV flow indices in a pilot cohort of MI patients to evaluate whether apical stasis (regional flow velocity, kinetic energy, residual blood volumes) post-MI is associated with LVT. The project sponsors and collaborators have a track record in successful translational CMR research and MRI physics, uniquely qualifying them to mentor on the proposed work. The novel information to be gained from this research has potential to impact clinical care by more precisely identifying post-MI flow patterns associated with LVT, thereby setting up future trials to test these parameters as predictors of LVT. The skills gained by the PI during this project will position him strongly for a successful independent research career in cardiovascular MRI.