[Non-invasive functional assessment of coronary stenosis by cardiac computed tomography]

The increased number of patients with coronary artery disease (CAD) is of great clinical relevance and involves a large burden of the healthcare system. The management of these patients is focused on relieving symptoms and improving clinical outcomes. Therefore, the ideal test would provide the correct diagnosis and actionable information. To this aim, several non-invasive functional imaging modalities are usually used as gatekeeper to invasive coronary angiography, but their diagnostic performance remains low with limited accuracy when compared to obstructive CAD at the time of invasive coronary angiography or invasive fractional flow reserve (FFR) assessment. For these reasons, an urgent need for non-invasive techniques that evaluate both the functional and morphological severity of CAD is growing. Coronary computed tomography angiography (CCTA) has emerged as a unique non-invasive technique providing coronary artery anatomic imaging. More recently, the evaluation of FFR with CCTA (FFRCT) has demonstrated high diagnostic performance compared to invasive FFR. Moreover, this tool has been proven to be more cost-effective than standard diagnostic pathways in large prospective multicenter trials, and to have a prognostic role. Additionally, stress myocardial computed tomography perfusion (stress CTP) represents a novel tool for the diagnosis of ischemia with high diagnostic accuracy. With advances in technical development, both static and dynamic computed tomography myocardial perfusion protocols offer functional assessment with an acceptable increase in radiation exposure. Compared to other imaging techniques, both FFRCT and stress CTP allow the combination of the anatomical evaluation of coronary arteries and the functional relevance of coronary artery lesions, having the potential to revolutionize the diagnostic paradigm of suspected CAD. FFRCT and stress CTP should be integrated in diagnostic pathways of patients with stable CAD and will likely result in a decrease of invasive diagnostic procedures and costs.