Cardiovascular molecular imaging: focus on clinical translation.

The past few decades have seen an explosion in the knowledge of the molecular basis of cardiovascular diseases owing to rapid advances in molecular biology research. An improved understanding of disease pathogenesis at the genomic, transcriptional, and proteomic levels has led to the discovery of promising experimental strategies for the prevention, diagnosis, and treatment of cardiovascular disease. Unfortunately, only a minute number of these strategies have survived the rigors of preclinical and clinical trials to become therapeutically useful. Furthermore, even these successful strategies must endure a prolonged process of translation from bench to bedside, partially owing to the lack of tools to directly interrogate the molecular events in patients. The strong impetus to develop noninvasive imaging techniques to visualize molecular changes in patients has given birth to the field of molecular imaging.1,2 Molecular imaging has its roots in nuclear medicine, in which radiolabeled imaging probes are injected into living subjects to assess the functionality of different organ systems. Unlike conventional diagnostic imaging techniques (eg, radiography and computed tomography [CT]) that delineate the anatomy of the cardiovascular system (eg, coronary luminal diameter), molecular imaging techniques have been designed and validated to study much smaller-scale molecular events (eg, gene expression) that may underlie disease processes. The complexity of molecular imaging lies in the requirement for molecular targeting, the design of which requires a solid understanding of the pharmacokinetics of the imaging probe and how it interacts with the molecular target. When the target is proven to be a biomarker, molecular imaging becomes a valuable tool for detecting disease before its clinical manifestation, stratifying disease severity, predicting disease progression, monitoring treatment efficacy, and prognosticating disease. These challenges must be met before the true potential of personalized medicine can be fully realized.3 Significant advances have been made in molecular imaging …