Recent technical developments in the ultrasonic imaging of the heart are utilized to provide a method for quantitative evaluation of the regional myocardial perfusion. Devised is a theoretical approach based on indicator dilution principles linking the tissue blood flow with the time dependence of changes in regional ultrasonic intensity produced by microbubbles. A computer model based on theoretical considerations was constructed in order to achieve optimization of the steps of the analysis. Several preliminary animal experiments were carried out in order to find the optimal experimental set up for verification of the method in vivo. The experiments involved computer analysis of the echocardiographic images obtained following direct left atrial injection of the ultrasonic contrast material under different flow conditions, such as ischemia and reactive hyperemia. Both the computer study and the animal experiments have shown promising results. The approach promises to provide a basis for a convenient noninvasive quantitative measurement of myocardial tissue blood flow.