Recent Advances in Imaging Inflammation Post-Myocardial Infarction Using Positron Emission Tomography

Abstract

Despite advances in medical and surgical therapy, some patients after a myocardial infarction still develop heart failure, a devastating disease that has a high rate of morbidity and mortality. Differences in the immune response to the myocardial damage may affect the healing process. Molecular imaging enables the interrogation of immune cell subsets that can aid or impair left ventricular recovery post-myocardial infarction. Visualization of patient-specific differences in the cellular and molecular process among patients post-myocardial infarction may lead to the development of personalized therapy to prevent remodeling and promote myocardial recovery. Positron emission tomography (PET) has emerged as a commonly used modality for imaging myocardial inflammation in both pre-clinical and clinical studies. While 18F-FDG continues to be investigated for its ability to track inflammation in small clinical trials, its relative short half-life and nonspecific uptake have prompted investigation into other PET tracers, including agents that image amino acid metabolism, mitochondrial transport proteins, cell surface receptors, and integrins. Two of the most innovative approaches include the use of reporter gene imaging and nanoparticles. Of these, the latter offers the added advantage of delivering a therapeutic payload. Finally, recent advances in PET instrumentation such as total-body imaging can allow the study of multi-organ dysfunction simultaneously (e.g., cardiac and brain inflammation after a heart attack) with high sensitivity. Moreover, with multi-isotope PET scanners, simultaneous observation of multiple positron emitting isotopes has enabled the examination of different biological processes with distinct molecular probes in a single scan setting. The development of advanced PET tracers for the visualization of the inflammatory cascade post-myocardial infarction may enable the development of immune modulating agents to promote left ventricular recovery.