RESUMO
ObjectiveTo determine the possibility of r eal-time perfusion imaging in the quantitative evaluation of myocardial perfusion in various segments of left ventricle. MethodsImages of ten anesthetized dogs were obtained at the mid-papillary muscle short-axis view with a real-time imaging system. Mechanical index (MI) was adjusted to 0.1 , 0.2 and 0.4 respectively, and frame rate was set at 20 Hz. Optison was infused intravenously at a rate of 0.1 , 0.2 and 0.5 ml/min, respectively. Images were recorded for 150 real-time frames commencing immediately after a couple of Doppler bursts. Myocardial opacification was assessed both visually and quantitatively for six segments of left ventricle (antero- and infero-septum, inferior, posterior, lateral and anterior wall). Myocardial signal intensity versus real-time frame curves were made and fitted to an exponential function: Y=A(1-e -?t ). ResultsUsing low MI (MI= 0.1 or 0.2 ) and with continuously infusion of Optison at a rate of 0.2 or 0.5 ml/min, real-time imaging resulted in sufficient myocardial opacification and left ventricular endocardial border definition, and displayed myocardial thickening and wall motion simultaneously. ConclusionsReal-time imaging has a potential in the quantitative assessment of myocardial perfusion, and allows simultaneous assessment of perfusion and myocardial function.