MRI evaluation of acute cardiovascular disease

点击翻译按钮获取中文摘要

This year represents the first full year of the NIH-Suburban MRI Center. This program has opened our research significantly with access to patients with symptoms of acute cardiovascular disease. The overall purposes of the research program remain: 1) development of cardiovascular MRI applications and analysis, 2) physiological assessment of myocardial perfusion, contractile function and myocardial viability, and 3) clinical evaluation of cardiovascular disease with an emphasis on myocardial ischemia and ischemic heart disease. Advances in MR image acquisition during the past year include a new high-resolution contrast enhanced scan that delineates myocardial infarction as a bright spot on images 10-30 minute after contrast administration. In animal studies completed this year, there is a tight correlation between MRI estimates of infarct size and pathological confirmation. In patient studies, this method appears to have very high sensitivity for old and new myocardial infarctions. It adds significant power to the emergency room triage of patients with chest pain. Issues remain regarding the specificity for reversible myocardial injury. This method is applicable to patients with hypertrophic cardiomyopathy undergoing alcohol ablation of the interventricular septum. Other advances in imaging include faster approaches that can now image left ventricular function with a temporal resolution of 31 ms per image. This method can quantitatively measure myocardial ejection fraction changes associated with bicycle exercise without the need for ECG gating or a breathhold. A new imaging technique has been developed to improve the contrast between the blood pool and the area of myocardial infarction. The infarct imaging work was largely perfected as a result of the collaboration with Suburban Hospital. A pilot study using these new imaging techniques to assess patients with chest pain in the emergency room suggests MRI is able to detect myocardial injury with comparable sensitivity to serial troponin measurements. In a few cases, the MRI has detected abnormalities before the blood test exceeded the normal limits. Although technical advances continue at a rapid pace, existing MRI methods appear quite promising in patients with coronary artery disease.