Arrhythmia-resolved 5D Flow MRI in Atrial Fibrillation and Stroke

项目摘要 房颤是最常见的持续性心律失常，也是缺血性心脏病的主要危险因素。 卒中。这是由于左心房内血栓的形成，抗凝治疗可以减轻血栓的形成。 但它本身也有出血的风险。平衡出血风险的当前临床治疗选择策略 卒中风险缺乏的抗凝治疗 为 卒中 有耐心的 这个 BE 预测 预测能力。血瘀证是Virchow三合一的重要组成部分 血栓形成和血流成像方法显示左心房血流速度减慢与 风险。然而，这些方法要么缺乏全面的3D测量，要么当 在心律不齐的情况下，这两者可能都是必要的，以开发准确的生物标志物来预测中风。 本项目的目标是进一步开发和优化一种可消除心律失常的血流成像MRI方法，以 能够捕捉心律失常期间时变的3D心房血流动力学，具有发生中风的可能性 用于指导药物治疗选择的生物标志物。 C 这项建议的第一个目标是发展和优化磁共振成像方法：解决心律失常的5D血流 MRI是一个维度的多维数据集：3D空间+心脏时间+心跳持续时间。对于几个人来说 在心律不齐期间测量的心跳持续时间(例如，短心跳、长心跳)我们将构建一个3D 为该心跳持续时间的一个心跳周期设置的时变幅度和速度数据。脉动的水流 Phantom能够模拟已知的心律失常，将允许优化采集时间和图像 重建方法和参数。我将开发两种不同的重建算法，这可以是 使用相同的原始数据进行重建。首先，将重建图像以测量最大差异 以分析患者体内心率变化的血流动力学。 其次，图像将基于从固定的、标准化的心跳长度获得的数据重建， 允许在对象之间进行比较，控制心跳持续时间本身的影响。这将会被测试 在此设置中，对照参考标准：2D实时相位对比度。临床合作者将帮助 优化的成像重建算法设计，确保体外移植到体内移植的成功 从第一个目标到后续目标的技术。第二个目标是通过一组队列在体内验证这项技术。 10例健康对照组和10例持续性房颤患者。这也将建立心率变量和 控制这些组之间的血流动力学差异。在第三个目标中，我们将测试 方法区分有卒中史和无卒中史的房颤患者。12持续性心房 有心栓性卒中病史的房颤患者和12例无心脏病史的持续性房颤患者 将招募中风病史。这一目标的目的是观察不同组之间的心房血流动力学的差异。 作为开发心房血流动力学生物标记物以改进药物治疗选择的先导。

Project Summary Atrial Fibrillation is the most common sustained cardiac arrhythmia, and it is a major risk factor for ischemic stroke. This is due to thrombus formation in the left atrium which may be mitigated by anticoagulation therapy but carrying its own bleeding risk. Current clinical therapy selection strategies balancing bleeding risk of anticoagulation therapy to stroke risk lack for stroke patient The be prediction predictive power. Blood stasis is a key component of Virchow's triad thrombus formation, and flow imaging methods have shown lowered left atrial velocities are associated with risk. However, these methods either lack omprehensive 3D measurement or must reject data when the is i n arrhythmia, where both of these may be necessary to develop accurate biomarkers to predict stroke. goal of this project is to further develop and optimize an arrhythmia resolved flow imaging MRI method to able to capture the time varying 3D atrial hemodynamics during arrhythmia with the potential to develop stroke biomarkers to guide medical therapy selection. c The first aim of this proposal is development and optimization of the MRI method: arrhythmia resolved 5D flow MRI, a multi-dimensional data set of dimension: 3D spatial + cardiac time + heartbeat duration. For several heartbeat durations measured during arrhythmia (e.g. short heartbeats, long heartbeats) we will construct a 3D time varying magnitude and velocity data set for one cardiac cycle for that heartbeat duration. A pulsatile flow phantom, capable of simulating a known arrhythmia, will allow the optimization of acquisition time and image reconstruction methodology and parameters. I will develop two different reconstruction algorithms, which can be reconstructed using the same raw data. First, images will be reconstructed to measure maximum differences across the varying heart rhythm in order to analyze the heart rate variable hemodynamics within a patient. Second, images will be reconstructed based on data acquired from fixed, standardized heartbeat lengths, allowing the comparison between subjects, controlling for the effect of heartbeat duration itself. This will be tested against the reference standard, in this setting: 2D real time phase contrast. Clinical collaborators will help with algorithm design of the optimized imaging reconstruction to ensure success of in vitro to in vivo translation of the technique from the first aim to subsequent aims. The second aim will validate this technique in vivo with a cohort of 10 healthy controls and 10 persistent atrial fibrillation patients. This will also establish heart rate variable and controlled hemodynamic differences between these groups. In the third aim, we will test the abilities of the method to discriminate between stroke history and no stroke history atrial fibrillation patients. 12 persistent atrial fibrillation patients with prior cardioembolic stroke history and 12 persistent atrial fibrillation patients without a stroke history will be recruited. The goal of this aim is to see differences in atrial hemodynamics between groups as a precursor to developing an atrial hemodynamic biomarker to improve medical therapy selection.