The integration of positron emission tomography (PET) and multidetector CT (PET/CT) technology provides a potential opportunity to delineate the anatomic extent and physiologic severity of coronary atherosclerosis and obstructive disease in a single setting. It allows detection and quantification of the burden of the extent of calcified and non calcified plaques, quantification of vascular reactivity and endothelial health, and identification of flow-limiting coronary stenosis. PET/CT also has the potential to identify high-risk plaques in the coronary and other arterial beds. Together, by revealing the degree and location of anatomic stenosis and their physiologic significance, and the plaque burden and its composition, integrated PET/CT can provide unique information that may improve noninvasive diagnosis of coronary artery disease (CAD) and the prediction of cardiovascular risk. In addition, this approach expands the diagnostic capability of nuclear cardiology to include atherosclerosis and may facilitate further study of atherothrombosis progression and its response to therapy, thus allowing assessment of subclinical disease.