Myocardial Contrast Echocardiography

Obstacles are those frightful things you see when you take your eyes off your goals. — –Anonymous In 1997, I wrote an invited review on myocardial contrast echocardiography (MCE) entitled “Myocardial Contrast Echocardiography: 15 Years of Research and Development” in the From-Bench-to-Bedside section of Circulation .1 Then, in 2003, Hiroshi Ito and I wrote a 2-piece invited review entitled “Microvasculature in Acute Myocardial Ischemia: Evolving Concepts in Pathophysiology, Diagnosis, and Treatment” in the Clinical Cardiology: New Frontiers section of Circulation .2,3 In this review for the New Drugs and Technology section of Circulation , I will provide a 25-year retrospective on MCE but with emphasis on more recent developments and remaining challenges for the field. I will limit myself to myocardial imaging and will not discuss imaging of other organs or the vascular system. Likewise, I will not address the therapeutic applications of microbubble-ultrasound interactions such as drug and gene delivery or sonothrombolysis.I have organized this review into 7 sections. I begin by briefly describing some historical and technical elements so that the reader unfamiliar with MCE will be able to follow the rest of the review. I then describe the more recent studies relating to the role of MCE in the diagnosis and prognostication in acute coronary syndromes and chronic coronary artery disease (CAD), followed by assessment of myocardial viability in chronic CAD. After that, I describe advances in site-targeted or molecular imaging and certain miscellaneous findings. Finally, I discuss the remaining challenges of MCE from a clinical adoption point of view.Initial MCE studies were performed in dogs to define in vivo the area at risk during acute coronary occlusion with the use of hand-agitated solutions.4–9 Shortly thereafter, the technique of sonication was described, which allowed the production of smaller microbubbles,10 and was …