Dual-bolus MR imaging enabled accurate measurement of absolute epicardial and endocardial perfusion across a wide range of blood flow rates (0 to >5.0 mL/min/g). Use of qualitative MR imaging measures such as the contrast enhancement ratio led to substantially underestimated hyperemic blood flow measurements.

Larger infarct size measured by 99mTc sestamibi imaging after acute myocardial infarction is associated with increased mortality risk during short-term follow-up.

An Ad vector expressing the VEGF121 cDNA induces collateral vessel development in ischemic myocardium and results in significant improvement in both myocardial perfusion and function. Such a strategy may be useful in patients with ischemic heart disease in whom complete revascularization is not possible.

Background-Managing chest pain in the emergency department remains a challenge with current diagnostic strategies.We hypothesized that cardiac MRI could accurately identify patients with possible or probable acute coronary syndrome. Methods and Results-The diagnostic performance of MRI was evaluated in a prospective study of 161 consecutive patients. Enrollment required 30 minutes of chest pain compatible with myocardial ischemia but an ECG not diagnostic of acute myocardial infarction. MRI was performed at rest within 12 hours of presentation and included perfusion, left ventricular function, and gadolinium-enhanced myocardial infarction detection. MRI was interpreted qualitatively but also analyzed quantitatively. The sensitivity and specificity, respectively, for detecting acute coronary syndrome were 84% and 85% by MRI, 80% and 61% by an abnormal ECG, 16% and 95% for strict ECG criteria for ischemia (ST depression or T-wave inversion), 40% and 97% for peak troponin-I, and 48% and 85% for a TIMI risk score Ն3. The MRI was more sensitive than strict ECG criteria for ischemia (PϽ0.001), peak troponin-I (PϽ0.001), and the TIMI risk score (Pϭ0.004), and MRI was more specific than an abnormal ECG (PϽ0.001). Multivariate logistic regression analysis showed MRI was the strongest predictor of acute coronary syndrome and added diagnostic value over clinical parameters (PϽ0.001). Conclusions-Resting