MRI Evaluation Of Acute Cardiovascular Disease

国家心肺血液研究所（NHLBI）/郊区医院心血管MRI研究项目的主要目的是开发新的方法，评估心血管疾病患者的MRI技术。 1)急性冠状动脉综合征的MRI检测。今年早些时候，我们发表了静息MRI扫描诊断非ST段抬高型急性冠状动脉综合征的敏感性和特异性高于心脏危险因素、ECG和肌钙蛋白。MRI检测急性冠状动脉综合征的敏感性和特异性分别为84%和85%，ECG异常分别为80%和61%，ST段压低或T波倒置分别为16%和95%，肌钙蛋白I峰值分别为40%和97%，TIMI风险评分>3分分别为48%和85%。MRI对缺血（p<0.001）、肌钙蛋白I峰值（p<0.001）和TIMI风险评分（p=0.004）的敏感性高于严格的ECG标准。MRI比异常ECG更具特异性（p<0.001）。多因素Logistic回归分析显示MRI异常是急性冠脉综合征最强的预测因子，并且与临床参数相比，MRI异常增加了具有统计学意义的诊断价值（p<0.001）。我们的结论是，静息MRI扫描显示出诊断操作特点，适合急诊科胸痛患者的分诊。 我们在第二个方案中扩展了这项工作，使用腺苷负荷MRI评估了141例肌钙蛋白阴性急性冠状动脉综合征患者。检测缺血性心脏病的总体敏感性和特异性均大于90%。异常腺苷负荷MRI具有显著的1年预后价值。 我们已经确定钆延迟增强心血管磁共振与心肌梗死的临床指标相关。本研究对急性心肌梗死患者在MI后平均2天进行成像。延迟增强的透壁范围可预测局部心肌功能的恢复。 我们已经开始了一个项目，旨在表征最近缺血心肌，并证明我们可以成像心肌灌注恢复后的缺血区域的风险。这可以被描述为“缺血性记忆成像”的一种形式。" 2)用MRI表征心肌存活性。我们还开发了一种相位敏感的重建方法，提高了心脏病发作图像的质量，并尽量减少用户选择的参数对心脏病发作的表观大小的影响。我们的组织病理学验证的相敏重建方法和验证研究表明，计算机算法可以准确地测量梗死面积在体内和体外图像，现在是按。我们还扩展了这项工作的特点IL-2心肌炎和社区获得性心肌炎。我们已经扩展了我们的验证相敏反转恢复方法的成像心肌梗死与另一项研究：心肌梗死成像中使用B1加权相控阵相敏反转恢复的抑制。 3)首过心肌灌注显像。我们已经扩展了我们的首过灌注方法，以提供定量分析方法。我们已经证明，MRI可以像微球注射一样准确地测量心肌灌注（仅在动物模型中可用的金标准方法）。我们正在翻译这些方法来分析人类双嘧达莫压力测试，并证实了基督教手稿中适用于人类的基本发现。 4)动脉粥样硬化斑块的MRI特征。我们已经扩展了我们先前的观察，即钆几乎使区分动脉粥样硬化斑块不同部分的能力加倍。我们研究了造影剂进入颈动脉粥样硬化纤维帽和脂质核心的动力学。 5)我们减少了DENSE图像上的图像伪影，这是一种心肌应变成像方法。 今年，我们证明了并行图像处理可以加快相位对比方法的获取速度。

The major aim of the National Heart, Lung and Blood Institute (NHLBI)/Suburban Hospital Cardiovascular MRI Research Project is to develop new approaches in assessing patients with cardiovascular disease with MRI technology. 1) Detection of acute coronary syndrome with MRI. Earlier this year, we published that a rest MRI scan had higher sensitivity and specificity for diagnosing non-ST elevation acute coronary syndrome than cardiac risk factors, ECG, and troponin. The sensitivity and specificity for detecting acute coronary syndrome was 84% and 85% by MRI, 80% and 61% by an abnormal ECG, 16% and 95% for ST depression or T-wave inversion, 40% and 97% for peak troponin-I, and 48% and 85% for a TIMI risk score >3. The MRI was more sensitive than strict ECG criteria for ischemia (p<0.001), peak troponin-I (p<0.001), and the TIMI Risk Score (p=0.004). The MRI was more specific than an abnormal ECG (p<0.001). Multivariate logistic regression analysis showed an abnormal MRI was the strongest predictor of acute coronary syndrome and added statistically significant diagnostic value over clinical parameters (p<0.001). We concluded that the resting MRI scan exhibited diagnostic operating characteristics suitable for triage of patients with chest pain in the emergency department. We have extended this work in a second protocol that used adenosine stress MRI to evaluate 141 consecutive patients with troponin-negative acute coronary syndrome. The overall sensitivity and specificity for detecting ischemic heart disease were both greater than 90%. An abnormal adenosine stress MRI had significant 1 year prognostic value. We have determined that gadolinium delayed enhancement cardiovascular magnetic resonance corrrelates with clinical measures of myocardial infarction. This study imaged patients with acute myocardial infarction an average of 2 days post-MI. The transmural extent of delayed enhancement predicted the recovery of regional myocardial function. We have started a project that aims to characterize recently ischemic myocardium and demonstrated that we can image the ischemic area at risk after myocardial perfusion has been restored. This can be described as a form of "ischemic memory imaging." 2) Characterizing myocardial viability with MRI. We also developed a phase sensitive reconstruction method which improves the quality of heart attack images and minimizes the influence of user selected parameters on the apparent size of the heart attack. Our histopathological validation of the phase sensitive reconstruction method and a validation study showing that a computer algorithm can accurately measure infarct size on in vivo and ex vivo images is now in press. We have also extended this work to characterize IL-2 myocarditis and community acquired myocarditis. We have extended our validations of the phase sensitive inverson recovery methods for imaging myocardial infarction with another study: Artifact suppression in imaging of myocardial infarction using B1-weighted phased-array combined phase-sensitive inversion recovery. 3) First pass myocardial perfusion imaging. We have extended our first pass perfusion methods to provide quantitative analysis methods. We have shown that the MRI can measure myocardial perfusion as accurately as microsphere injections (a gold standard method only usable in animal models). We are in the process of translating these methods to analyze human dipyridamole stress tests and have corroborated the basic findings from the Christian manuscript apply to humans. 4) MRI characterization of atherosclerotic plaque. We have extended our prior observations that gadolinium nearly doubles the ability to discriminate different portions of the atherosclerotic plaque. We have studied the kinetics with which contrast enters the fibrous cap and lipid core of carotid atheroma]. 5) We have reduced image artifacts on DENSE images, a method for imaging myocardial strain. This year, we demonstrated that parallel image processing can accelerate the rate of acquiring phase contrast methodologies.