Effects of tissue anisotropy and contrast acoustic properties on myocardial scattering in contrast echocardiography

In this study we explored the potential effects that tissue anisotropy, in conjunction with the acoustic properties of contrast, may have on quantitat ive measurements of myocardial perfusion with the use of ultrasonic contras t agents. We used a computer simulation of the parasternal short-axis view, based on previously measured values for the anisotropy of backscatter and attenuation of myocardium, to predict the backscattered energy from 18 spec ific regions within the heart before and after myocardial contrast perfusio n. Results demonstrated a regional variation of contrast enhancement in the short-axis view and variations caused by incremental increases in contrast level for specific myocardial regions. Thus quantitative assessment of myo cardial perfusion with contrast echocardiography is influenced by the aniso tropic properties of the myocardium, and the resulting postcontrast image w ill depend on the Interaction between tissue properties and contrast acoust ic properties. The degree of myocardial enhancement caused by the presence of contrast may depend on the spatial position of the specific region Inves tigated with respect to the transducer and the amount of contrast in the my ocardium.