Prediction of Transmural Extent of Infarction with Contrast Echocardiographically Derived Index of Myocardial Blood Flow and Myocardial Blood Volume Fraction: Comparison with Contrast-enhanced Magnetic Resonance Imaging

Background: We sought to determine the accuracy of myocardial contrast echocardiography (MCE)-derived index of myocardial blood flow and myocardial blood volume fraction (MBVF) in predicting transmural extent of infarction and wall-motion recovery. Methods: Low and high mechanical index MCE and contrast-enhanced magnetic resonance imaging were performed 5 to 7 days after successful percutaneous revascularization in 30 patients with acute myocardial infarction and regional wall-motion change was assessed 3 months later. The index of myocardial blood flow was calculated as A × β (dB/s) using the equation y = A (1 - e^-βt), which fits the replenishment curve of low mechanical index MCE. The MBVF (mL/100 g myocardium) was calculated as 100 × 10^{relative contrast intensity [CI]/10}, using the relative CI by subtracting the cavity CI from the adjacent transmural CI using high mechanical index MCE. The contrast-enhanced magnetic resonance imaging-derived transmural extent of delayed hyperenhancement (DE) in 16 segments were measured and compared with corresponding MCE data. Results: Among 480 segments, 382 measurable segments were subdivided into 5 groups as follows: no DE, 1% to 25% DE, 26% to 50% DE, 51% to 75% DE, and 76% to 100% DE. An increment of the extent of DE was significantly related to a decrement of A × β (P < .001) and MBVF (P < .001). The optimal cut-off MBVF for predicting greater than 50% DE was 1.92 mL (sensitivity 82%, specificity 73%, P < .01), and persistently dysfunctional motion was 1.81 mL (sensitivity 74%, specificity 75%, P < .01). Conclusion: The MCE-derived A × β and MBVF can be effective predictors of transmural extent of infarction and wall-motion recovery in the reperfused acute myocardial infarction.