Molecular Imaging of Inflammation in Ischemic Heart Disease

Ischemic heart disease is caused by atherosclerosis, the build-up of plaque in the coronary arteries, which can lead to the development of heart attacks and heart muscle damage. Despite the advent of medical and surgical therapy to prevent and treat atherosclerosis and its adverse clinical effects, ischemic heart disease remains a leading cause of morbidity and mortality. Recent studies have suggested that the immune system may play a greater role in the development of plaque rupture and adverse left ventricular remodeling after myocardial infarction. Understanding the molecular processes by which inflammation contributes to the pathophysiology of ischemic heart disease is, therefore, worthwhile. This review focuses on new molecular imaging techniques to visualize immune cells to study their contribution to ischemic heart disease.

A common technique applied to imaging inflammation in ischemic heart disease is targeting the up-regulation and trafficking of immune cells, which may contribute to the adverse consequences associated with atherosclerosis. In the past five years, advances in cell labeling for imaging with PET and MRI, including radioisotopes and nanoparticles, have confirmed that inflammatory cells can be visualized in vivo and in greater abundance in unstable cardiovascular disease and in areas of ischemic damage. The major criticisms of these studies to date include their small sample size, lack of histological correlation, limited association with long-term outcomes, and bias toward macrophage imaging.

While much progress has been made in imaging inflammation in ischemic heart disease over the past five years, additional studies in larger cohorts with histological validation and outcome correlation are needed. Nevertheless, imaging inflammation using PET or MRI has the potential to become an important adjunct tool to improve the diagnosis, risk stratification, and therapeutic monitoring of patients with ischemic heart disease.