Real-time contrast echo assessment of myocardial perfusion at low emissionpower: First experimental and clinical results using power pulse inversionimaging

Power pulse inversion (PPI) has been, developed for echocontrast specific i maging in order to reduce destruction of microbubbles. The purpose of this study was to evaluate PPI for real-time contrast echocardiography. Therefor e, in, vitro studies in a physiological flow-phantom and clinical examinati ons in, patients with coronary artery disease were performed. The in vitro results of this study indicate that PPI allows real-time imaging at low emi ssion power and is almost nondestructive to contrast microbubbles of Defini ty. At this low emission power a strong linear relationship between the dos age of the contrast agent and the resulting PPI signal intensity was found (R = 0.998, p < 0.001). In the clinical examinations real-time imaging usin g low mechanical index PPI resulted in strong myocardial signals and a comp lete filling of the cavities indicating absence of bubble destruction. Most striking was the ability of PPI to display myocardial thickening and wall motion simultaneously with the assessment of myocardial contrast replenishm ent following ultrasound induced bubble destruction by high power frames. W e conclude that PPI allows nondestructive contrast imaging both in experime ntal and clinical settings. Therefore, real-time imaging of myocardial perf usion, and real-time assessment of contrast replenishment following ultraso und induced destruction of microbubbles is feasible. Moreover, PPI allows s imultaneous assessment of perfusion and myocardial function.