MYOCARDIAL CONTRAST ECHOCARDIOGRAPHY - RELATION BETWEEN ONLINE AND OFF-LINE ASSESSMENT OF MYOCARDIAL PERFUSION

Background: Quantitative assessment of myocardial perfusion by myocardial contrast echocardiography has been made possible by the use of custom-made off-line video-intensity programs. A standardized program that could be used by all investigators would improve the reproducibility of results and enhance its clinical utility. Methods and Results: The purpose of this study was to determine if the assessment of myocardial perfusion by contrast echocardiography using a new commercially available, quantitative on-line software program correlates with an off-line custom-made video-intensity program previously validated by our laboratory and with radiolabeled microspheres, under various experimental myocardial perfusion conditions. Two of the measured myocardial contrast echocardiographic parameters (peak intensity, area under the time-intensity curve [area]) correlated well among on-line and off-line methods and radiolabeled microspheres, especially when the data were ''normalized'' by comparing percent change from baseline or a ratio of ischemic to nonischemic myocardium. The third myocardial contrast echocardiographic parameter examined, half-time of the peak intensity on the washout limb of the curve (t1/2), correlated only when the percent change from baseline was compared between the two methods or when the off-line method was compared with radiolabeled microspheres. Conclusion: The results of this investigation add further support to the potential use of myocardial contrast echocardiography to evaluate serial changes in myocardial perfusion. Whether using the off-line or on-line analysis system, it is important that: (1) multiple regions of interest are examined during a single injection: (2) no log compression or postprocessing is performed on the returning ultrasound signal to avoid distortion of the acquired data; and (3) myocardial translation and rotation are corrected with an internal reference system.