Advances in ultrasonic engineering have made possible the development of "intelligent" microparticles with the capacity of passing through the pulmonary circulation in sufficient amount to acquire images of the left heart, making possible the evaluation of myocardial perfusion. Although the Food and Drug Administration of the United States has approved several contrast agents for use in ventricular opacification and visualization of endocardial borders in subjects that have suboptimal studies, at this time, it has not approved any agent of contrast for use in myocardial perfusion. Currently, there are two multicenter studies on a great scale that were exclusively designed for myocardial perfusion in comparison with nuclear medicine and angiography. Our laboratory has had the opportunity to actively participate in both trials. This revision includes the design, interpretation criteria, and preliminary results of CARDIOsphere. As well, we are presenting the interpretation criteria of the AI-700 bubble, which is currently in phase III of clinical investigation. Myocardial perfusion assessment with contrast echocardiography faces several challenges that need to be addressed before it becomes established as an efficient alternative. A common limitation is the viability of this method in subjects with bad acoustic window, the creation of intrinsic artifacts to the system, as distal and lateral attenuation; the unavoidable learning curve, and the settlement of defect quantification criteria.