Purpose: Quantitative myocardial contrast echocardiography (MCE) is able to measure myocardial perfusion with kinetics data from replenishment curves. This study was aimed to investigate the usefulness of contrast echocardiography in prediction of successful reperfusion after percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) lesion. Method: 147 myocardial segments of 34 patients (mean age=60.0짹14.9 years, 25 males) with documented CTO lesion in coronary angiography were divided into two groups according to results of intervention : Group I (segments that successfully reperfused with PCI, n=102 segments) and group II (segments that fail to reperfuse with PCI, n=45 segments) . Before PCI, the plateau acoustic intensity(A) and the rate of increase in acoustic intensity (棺) of replenishment curves, wall motion score (WMS) were measured in contrast echocardiographic images and compared between two groups. Results: The plateau acoustic intensity(A) of contrast replenishment curves were significantly higher in group I than in group II (6.5짹 5.47 vs. 4.7짹 3.99, p=0.029). The rate parameter (棺) of contrast in involved myocardium (0.69짹 0.92 vs. 2.61짹 8.80, p=0.166) and WMS (1.89짹 0.89 vs. 1.69짹 0.73, p=0.170) were not different between two groups. On receiver operation curve analysis, peak intensity (慣) showed powerful diagnostic power to predict successful PCI for CTO lesion (area under the curve=0.659, p=0.004). The optimal cutoff value of the plateau acoustic intensity(A) was 4.3 (sensitivity: 64.8%, specificity: 60.0%). Conclusion: This study results suggested that peak intensity of involved myocardial segments measured by contrast echocardiography before coronary intervention is useful for predict favorable results in CTO lesion. Key Words: plateau acoustic intensity, contrast echocardiography, chronic total occlusion