Atherosclerosis is a systemic, chronic inflammatory disease of the intima layer of the vessel wall affecting both large and medium-sized muscular arteries. The process of atherosclerosis is complex and develops progressively during time, already starting in the 2nd and 3rd decade of life1. Symptoms do not occur during the earlier phases of atherosclerosis and remain absent for several decades2. Chronic symptoms occur when an atherosclerotic plaque causes a significant obstruction of the coronary arteries, which limits the blood supply to the heart. Patients typically develop chest pain (angina pectoris) during exercise, when the heart needs more oxygen, but symptoms disappear after a short period of rest. Acute clinical manifestations may develop from advanced, high-risk lesions (e.g. plaques with a large necrotic, lipid-rich core and thin fibrous cap), which ruptures causing a thrombotic lesion with complete or partial blockage of the blood supply to the heart followed by myocardial infarction or sudden cardiac death. As in many other industrialized countries, atherosclerosis is the number one cause of mortality in the Netherlands3. Conventional coronary angiography is considered to be the gold standard to evaluate the impact of atherosclerosis on the coronary lumen. This is an invasive technique that requires puncture of a peripheral artery, advancement of a catheter towards the heart, and injection of contrast material directly into the coronary arteries. During this procedure, conventional X-ray images are obtained which allows real-time evaluation of high-resolution images of the coronary lumen. The degree of coronary stenoses can be calculated using quantitative contour detection algorithms.