The study of endothelial dysfunction by positron emission tomography (PET) allows a non-invasive evaluation of the endotheliums role in the maintenance of tone and vascular homeostasis, thus the determination of regional myocardial flow, myocardial flow reserve, endothelium dependent vasodilatory index and inflammation level in the vascular wall in atherosclerosis and autoimmune diseases. Endothelial dysfunction results in significantly impaired physiological responses that often lead to the development of coronary atherosclerosis and coronary artery disease (CAD). PET allows the early recognition of endothelial dysfunction in order to evaluate a possible and beneficial response to medical interventions in the atherosclerosis process. This can help to establish a prognosis based in the early detection of patients at risk of CAD and offers the opportunity for early treatment. This article reviews the current knowledge regarding a non-invasive assessment for endothelial dysfunction and proposes the potential use of this promising technique for early detection of this prognostic marker in the coronary atherosclerotic process.