Challenges, Current Status, and Future Utility of PET in Cardiovascular Disorders

1364 Objectives: Over the past decade, cardiovascular imaging has made great advances by providing comprehensive information in regards to the anatomic structure of the vasculature, heart, and heart function, thus enabling physicians to accurately diagnose a disease and provide better patient care. Moreover, complicated diseases require the integration of multiple imaging modalities to effectively manage such conditions. In particular, PET imaging has been combined with other imaging modalities such as computed tomography (CT) and magnetic resonance imaging (MRI) to improve its uses in clinical practice. CT and MRI offer anatomical imaging, whereas PET imaging provides an unparalleled advantage with highly sensitive imaging capable of quantifying disease activity. In fact, the true potential of molecular imaging approaches with PET lies in its ability to detect and quantify disease activity at a molecular level well before structural pathology becomes evident. The applications of PET are strengthened with the use of tracers such as 18-fluorodeoxyglucose (FDG) and 18-sodium fluoride (NaF) in cardiovascular diseases like coronary heart disease (CHD). PET is well known to be an important tool in assessing cardiac viability and perfusion in CHD. Furthermore, PET has received recognition for its ability to estimate absolute myocardial blood flow. This would allow for patients to be risk stratified for appropriate management and benefit from timely revascularization. The disadvantage of commonly used tracers in assessing myocardial perfusion is their short half-lives. F-18 flurpiridaz, a perfusion tracer under trial, has shown promising results in having a longer half-life and better pharmacokinetics than routinely used perfusion agents. There has been an increasing trend to utilize PET imaging in inflammatory conditions such as cardiac sarcoidosis, fever of unknown origin, and vasculitis disorders. However, the ongoing challenge to employ nuclear imaging to detect inflammation is hindered by the low specificity of available tracers. Future utility of PET will be partly dependent on the introduction of novel radiopharmaceutical tracers into routine practice. In addition, cardiac hybrid imaging with PET/MRI is another promising use for these scanners as myocardial scars will show a late gadolinium enhancement, helping to differentiate subendocardial and transmural infarcts. Taking into consideration the recent advances in nuclear cardiology, the ongoing challenges in this field may become opportunities in the future. In this educational exhibit, we will review the following: 1) Applications of PET in nuclear cardiology, 2) Technical challenges faced with PET based cardiac imaging, 3) Promising new tracers in nuclear cardiology, 4) Hybrid imaging in nuclear cardiology