Clinical Molecular Imaging of Inflammation and Calcification in Atherosclerosis

Abstract

Atherosclerotic cardiovascular disease is the leading cause of mortality worldwide [1]. Once considered relatively inert gruel deposition on the vessel wall, atherosclerosis is now recognized as a highly dynamic and complex process. It involves many molecules and risk factors that trigger its development, promote its progression, and lead to complications that include atherothrombotic events in the setting of vulnerable plaque ruptures. Traditional imaging tools, such as coronary angiography, have long been used to evaluate atherosclerotic disease. Angiography provides well-validated assessments of risk through high-resolution visualization of luminal narrowing, but these luminal evaluations provide little insight into the atherosclerotic plaques that result in major cardiac events. CT angiography allows evaluation of plaque morphology and the detection of plaques at increased risk of rupture and of patients at higher risk of acute coronary events. In addition, evolving molecular imaging approaches also enable identification of high-risk plaque features and the activity of biological processes underlying the development, progression, and clinical complications of atheromatous plaques [2, 3]. Among the molecular imaging approaches, positron emission tomography–computed tomography (PET-CT) has been used and validated most extensively in human studies. This chapter focuses on PET-CT approaches to identify and characterize high-risk plaque features, and how these tools may be used to gain biological and clinical insights. Only clinically relevant imaging tools are highlighted.