DYNAMIC 3D TAGGED MRI OF THE CARDIAC CYCLE IN ISCHEMIA

在最初的资助期间，高效心肌的发展 实现了基于MR标记的三维应变图绘制。最基本的 我们研究的基础是核磁共振是唯一能够 提供高分辨率、空间配准的功能地图和 在完好无损的人体内进行灌流。3D MR应变测绘也是唯一的非 一种能够明确匹配特定冠状动脉的侵入性方法 具有真正量化的当地功能参数的领土。与 有效的血管重建术和早期溶栓技术的出现 已经变得重要的不仅仅是检测冠状动脉的存在 疾病(CAD)在发病前不可逆的损伤，也要 量化其在缺血损伤前后的功能影响。因此，在 是次续期申请，我们的主要目标仍然是 心肌缺血损伤前后状态的特征。我们 将继续探索3D标记的潜力，但将结合它 其灌注参数由微球和MR灌注得到 方法：研究方法。因为这项研究的临床相关性最终是 基于高效的图像采集和分析，我们将完成 我们的方法适用于回声平面成像。我们的具体目标 将检验以下假设： 1)因为已知冠脉血流灌注和局部功能是敏感的 再加上缺血性损伤之前，是否有可能准确地量化 应用分级法评价特定心肌区的功能储备 药理应激水平和重复的3D应变测量？vbl.使用 我们将定量地建立分级的多巴酚丁胺挑战(并对我们的 知识，第一次)冠状动脉之间的确切相关性 在犬模型中进行灌流储备和局部应变。到时候我们会的 在确诊为冠心病的患者身上测试我们的方法。 2)损伤后心肌损伤的准确特征仍然是 脑梗塞后患者的管理中的关键挑战 抢救有危险的心肌是当务之急。通过精确匹配 对比度增强的模式和应变图，有没有可能 描述坏死和可挽救的心肌的真实范围？基座 关于有希望的初步结果，我们建议将菌株和 犬实验性非手术再灌流模型的血流灌注数据 实现对梗死性眩晕的准确评估和识别 而是可挽救的心肌。我们还将继续我们的临床探索 用类似的方法诊断急性再灌注性脑梗塞。

During the initial funding period, the development of efficient myocardial 3D strain mapping with MR tagging was achieved. The fundamental underpinning of our research is that MRI is the only methodology able to provide high resolution, spatially registered maps of function and perfusion in the intact human. 3D MR strain mapping is also the only non- invasive method capable of unambiguously matching specific coronary territories with truly quantitative parameters of local function. With the advent of effective revascularization techniques and early thrombolysis it has become important to not only detect the presence of coronary artery disease (CAD) prior to the onset of irreversible injury, but also to quantify its functional impact before and after ischemic injury. Thus, in this renewal application, our central objective will remain the characterization of pre- and post-myocardial ischemic injury states. We will continue to explore the potential of 3D tagging but will combine it with perfusion parameters derived from both microsphere and MR perfusion methods. Because clinical relevance of the research is ultimately predicated upon efficient image acquisition and analysis, we will complete the adaptation of our methods to Echo-Planar imaging. Our specific aims will test the following hypotheses: 1) Since coronary perfusion and local function are known to be sensitively coupled prior to ischemic insult, is it possible to accurately quantify the functional reserve of specific myocardial territory using graded levels of pharmacologic stress and repeated 3D measures of strain? Using graded Dobutamine challenges we will establish quantitatively (and, to our knowledge, for the first time) the exact correlation between coronary perfusion reserve and developed local strain in a dog model. We will then test our methods on patients with proven CAD. 2) Accurate characterization of myocardial damage after injury remains a key challenge in the management of the post-infarct patient in whom salvage of the myocardium at risk is a priority. By accurately matching patterns of contrast enhancement and strain maps, is it possible to characterize the true extent of necrotic and salvageable myocardium? Based on promising preliminary results we propose to combine strain and perfusion data in an experimental non-surgical dog model of reperfused infarction to achieve accurate assessment and identification of stunned but salvageable myocardium. We will also continue our clinical exploration of acute reperfused infarction in man with similar methods.