Mri Evaluation Of Acute Cardiovascular Disease

国家心肺血液研究所(NHLBI)/郊区医院心血管MRI研究项目的主要目标是开发新的方法，利用MRI技术评估心血管疾病患者。到目前为止，我们的重点是四个具体目标。 1)MRI检查急性冠脉综合征。MRI诊断急性冠脉综合征的敏感性和特异性分别为84%和85%，心电图异常分别为80%和61%，ST段压低和T波倒置分别为16%和95%，肌钙蛋白I峰值分别为40%和97%，TIMI风险评分分别为48%和85%。MRI诊断急性冠脉综合征的敏感性高于严格的心电图缺血标准(P&lt；0.001)、峰值肌钙蛋白I(P&lt；0.001)和TIMI风险评分(P=0.004)。核磁共振比异常心电图更具特异性(p&lt；0.001)。多因素Logistic回归分析显示，MRI异常是急性冠脉综合征的最强预测因子，其对临床参数的诊断价值具有统计学意义(p&lt；0.001)。我们认为，静息MRI扫描具有诊断性操作特征，适合急诊科胸痛患者的分诊。 2)MRI评价存活心肌的能力。我们开发了一种方法，可以在心脏病发作后一天通过一次采集区分梗死心肌、顿抑心肌和正常心肌[Radiology 2002，Press]。我们还提出了一种相位敏感的重建方法。这提高了心脏病发作图像的质量，并将用户选择的参数对心脏病发作的表观大小的影响降至最低[Kellman P，Arai AE，McVeigh ER，Aletras AH。相敏反转恢复技术检测心肌梗死的延迟增强。《医学中的磁共振》2002年47(2)：372-383]。在这项工作的基础上，我们已经能够使用这种新方法将心脏病发作的成像速度提高3-4倍[Arai等人，国际磁共振医学学会，2002年5月，檀香山]。另一个两倍的加速目前正在积极调查中。 3)首次通过心肌灌注成像。我们开发并验证了一种更快的方法来成像NIH的心肌灌注(血液供应)[Epstein FH，London JF，Peters DC，Goncalves LM，Taylor J，Balaban RS，Arai AE]。多层首过心脏灌注MRI：在心肌梗死模型中的验证。Magn Reson Med.2002年3月；47(3)：482-91]。这种核磁共振成像方法的优点包括非常快速、接近实时地检测到灌注异常，分辨率至少是正电子发射计算机断层扫描的两倍，是标准铊扫描的4倍。有广泛的潜在应用[ARAI AE。磁共振首先通过心肌灌注成像。MRI主题2000：11(6)：383-398]。在NIH的过去一年里，我们已经证明了MRI可以像微球注射一样精确地测量心肌灌注(这是一种仅在动物模型中使用的金标准方法)[Christian等人。2001年美国心脏协会科学会议，正在审查中以供出版]。 4)动脉粥样硬化斑块的MRI表现。我们将患者和志愿者动脉壁的高分辨率MRI表现与炎症的血液测试相关联，炎症是动脉粥样硬化发展和进展中的一个重要过程[Weiss CR、Arai AE、BUI MN、Agyeman KO、Waclawiw MA、Balaban RS、Cannon RO 3。动脉壁MRI特征与人类血清炎症标志物升高有关。J Magn Reson成像。2001年12月；14(6)：698-704]。我们能够检测到壁上细微的异常，这些异常预示着血液测试的异常，而目前的临床方法似乎不太可能检测到这些异常。我们将这项工作扩展到颈动脉已知显著阻塞的患者中，发现MRI造影剂Gd几乎使区分动脉粥样硬化斑块不同部分的能力翻了一番[Wasserman BA，Smith WI，Trout HH Third，Cannon RO Third，Balaban RS，Arai AE]。颈动脉粥样硬化：Gd增强双斜向磁共振成像的活体形态特征初步结果。放射学。2002年5月；223(2)：566-73]。

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. To date, we have focused on four specific aims. 1) Detection of acute coronary syndrome with MRI. 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. 2) Characterizing myocardial viability with MRI. We developed a method that can differentiate infarcted myocardium, stunned myocardium, and normal myocardium one day after heart attack with a single acquisition [Radiology 2002, in press]. 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 [Kellman P, Arai AE, McVeigh ER, Aletras AH. Phase-sensitive inversion recovery for detecting myocardial infarction using gadolinium-delayed hyperenhancement. Magnetic Resonance in Medicine 2002 47(2):372-383]. Expanding upon this work, we have been able to use this new method to increase the speed of imaging a heart attack by a factor of 3-4 [Arai et al, International Society of Magnetic Resonance in Medicine May 2002, Honolulu]. Further acceleration by another factor of two is currently under active investigation. 3) First pass myocardial perfusion imaging. We developed and validated a faster method for imaging myocardial perfusion (blood supply) at the NIH [Epstein FH, London JF, Peters DC, Goncalves LM, Taylor J, Balaban RS, Arai AE. Multislice first-pass cardiac perfusion MRI: validation in a model of myocardial infarction. Magn Reson Med. 2002 Mar;47(3):482-91]. The advantages of this MRI method include very rapid, near real time detection of perfusion abnormalities at a resolution at least double that achieved by PET scans and 4 times the resolution of a standard thallium scan. There are a wide range of potential applications [Arai AE. Magnetic Resonance First Pass Myocardial Perfusion Imaging. Topics in MRI 2000:11(6):383-398]. During the last year at the NIH, we have shown that the MRI can measure myocardial perfusion as accurately as microsphere injections (a gold standard method only usable in animal models) [Christian et al. Scientific Sessions of the American Heart Association 2001 and in review for publication]. 4) MRI characterization of atherosclerotic plaque. We have correlated high-resolution MRI findings in the arterial wall of patients and volunteers with blood tests of inflammation, a process important in the development and progression of atherosclerosis [Weiss CR, Arai AE, Bui MN, Agyeman KO, Waclawiw MA, Balaban RS, Cannon RO 3rd. Arterial wall MRI characteristics are associated with elevated serum markers of inflammation in humans. J Magn Reson Imaging. 2001 Dec;14(6):698-704]. We were able to detect subtle abnormalities in the wall that predicted abnormal blood tests that seem unlikely to be detectable by current clinical methods. We have extended this work in patients with known significant blockages in the carotid arteries and find that the MRI contrast agent gadolinium nearly doubles the ability to discriminate different portions of the atherosclerotic plaque [Wasserman BA, Smith WI, Trout HH 3rd, Cannon RO 3rd, Balaban RS, Arai AE. Carotid Artery Atherosclerosis: In Vivo Morphologic Characterization with Gadolinium-enhanced Double-oblique MR Imaging Initial Results. Radiology. 2002 May;223(2):566-73].