Abstract Coronary computed tomography (CCT) is a non-invasive imaging method that allows visualization of the epicardial coronary arteries. The diagnostic and prognostic role of CCT has been demonstrated by various randomized trials to such an extent that it has been included as a Class I, level of evidence B recommendation in the latest European Society of Cardiology (ESC) guidelines for the diagnosis of chronic coronary syndrome in patients at intermediate-low cardiovascular risk. In addition to the anatomical evaluation, the CCT allows to evaluate the presence of high-risk characteristics of the atherosclerotic plaque (napkin-ring sign, positive remodelling, spotty calcification, and low-attenuation plaque), thus discriminating the stability of the atheromatous pathology. Furthermore, among the potential of cardiac CT in the emergency department, the possibility of making a triple rule-out must be underlined, excluding three potential big killers as the cause of acute chest pain: acute coronary syndrome, pulmonary embolism, and aortic dissection. Various randomized clinical studies have demonstrated that the prognosis of the patient with chronic coronary artery disease (CAD) improves only if a haemodynamically significant stenosis is treated, generally investigated with invasive fractional flow reserve (FFR); CCT technological advances have made it possible to create an algorithm for calculating the FFR-CT, an index of haemodynamic significance of coronary stenosis, whose correlation with the invasive FFR data and, consequently, with the prognosis has been demonstrated of patients with CAD.