Perfusion and Specific Radioprobes for Cardiac Imaging

Abstract

Major advancements have been made in treating cardiovascular disease. However, improving diagnosis is crucial, because the detection of the early stages of disease would allow preventative approaches therapy. Myocardial perfusion imaging is in clinical use for decades and is an effective tool for diagnosis, and longterm follow-up of patients with suspected or known coronary artery disease. The technetium-based agents, 99mTc-sestamibi and 99mTc-tetrofosmin, are widely used myocardial blood flow tracers. However, since both present drawbacks in their biodistribution properties, there is now resurgence in the study of both neutral and cationic technetium agents to further improve the characteristics of perfusion radiopharmaceuticals. Despite all the success of perfusion imaging, a unique strength of nuclear imaging is its ability to provide tools for imaging processes at molecular and cellular levels in intact organisms under a wide variety of physiologic conditions. Advances in new specific imaging agents that identify myocardium injury and cellular dysfunction may contribute to the improvement of diagnosis and eventually better therapeutic approaches. In this communication, we will review perfusion agents and their biological mechanism of uptake. We will also discuss examples of target-specific radiopharmaceuticals for cardiac imaging, including advances in pre-clinical imaging approaches.