Magnetic Resonance Imaging Evaluation of Acute Cardiovascular Disease

心肌灌注成像仍然是该小组感兴趣的一个领域。一项针对25名正常人和25名冠心病患者的临床研究已于今年完成。本研究表明，潘生丁负荷试验对冠心病的诊断具有临床相关的敏感性和特异性。这一方法似乎是临床上第一个能够常规区分心内膜和心外膜血流灌注异常的方法。肥厚型心肌病患者也有定位于心内膜的血流灌注异常。在铊上有明显左室腔扩张的受试者，MRI灌注异常主要是肥厚最严重区域的心内膜，而不是弥漫性分布。完成了一项验证性研究，将MRI和荧光微球测定的心肌血流量进行比较。在造影剂到达后的固定时间间隔，心肌造影剂增强率与心内膜下微球测量在空间和相对灌注量方面都有很好的相关性。使用相同的原理开发了更快的电影MRI应用程序，以加速MRI灌注成像。今年的一项技术研究描述了使用短分段回波平面读数来提高电影MRI(磁共振成像)效率的原理。第二项技术研究描述了这一方法的成像参数的优化。这些研究表明，心脏成像的最佳读出时间为1.5特斯拉。一方面，读出持续时间受信噪比和扫描效率的限制。在较长的读数持续时间内，血流相关伪影和几何失真占主导地位。这些更快的成像方法的经验使我们能够通过实时成像获取心脏的体积数据，并在自行车运动后立即冻结心脏运动。我们正在研究与动脉粥样硬化相关的血管炎症。我们开发了一种磁共振成像方法，旨在检测血管壁的炎症。我们还确定了一些肥厚型心肌病患者的肥厚心肌呈三维螺旋状。--磁共振成像、缺血性心脏病、心肌缺血、心肌梗死、心肌灌注、动脉粥样硬化--人类受试者

Myocardial perfusion imaging continues to be an area of interest for the group. A clinical study of 25 normal subjects and 25 patients with coronary artery disease was completed this year. This study indicated the dipyridamole stress MRI studies have clinically relevant sensitivity and specificity for detection of coronary artery disease. This methodology appears to be the first clinically available approach capable of routinely differentiating endocardial from epicardial perfusion abnormalities. Patients with hypertrophic cardiomyopathy also have perfusion abnormalities that localize to the endocardium. In subjects with apparent left ventricular cavity dilatation on thallium, the MRI perfusion abnormality is primarily endocardial in the most severely hypertrophic regions rather than diffusely distributed. A validation study was completed comparing myocardial blood flow determinations by MRI and fluorescent microspheres. Myocardial contrast enhancement ratio at a fixed time interval after contrast arrival correlates well with subendocardial microsphere measurements both spatially and in terms of relative perfusion. Faster cine MRI applications have been developed using the same principles developed to accelerate MRI perfusion imaging. One technical study this year describes the principle of using short segmented echoplanar readouts to increase the efficiency of cine MRI (magnetic resonance imaging). A second technical study characterizes the optimization of imaging parameters for this methodology. These studies indicate that there is an optimal readout duration for cardiac imaging at 1.5 Tesla. On one side readout duration is bounded by signal-to-noise and scan efficiency. At longer readout durations, blood flow related artifacts and geometric distortion dominate. Experience with these faster imaging methods has allowed us to acquire volumetric data of the heart with real-time imaging and to freeze cardiac motion in immediately after bicycle exercise. We are studying vascular inflammation associated with atherosclerosis. We developed an MRI methodology designed to detect inflammation in the vascular wall. We have also determined that hypertrophic myocardium in some patients with hypertrophic cardiomyopathy is in a 3-dimensional spiral. - Magnetic resonance imaging, ischemic heart disease, myocardial ischemia, myocardial infarction, myocardial perfusion, atherosclerosis - Human Subjects