An anomalous coronary artery from the opposite sinus of Valsalva (ACAOS) represents a congenital disorder with an anomalous location and/or course of the coronary vessel. The prevalence of ACAOS in the general population is around 1 % and they are mostly clinically insignificant and remain often undetected. However, some variants of ACAOS are associated with adverse cardiac events. The possible presence of an interarterial/intramural course is the primary cause for an oval proximal vessel shape and/or proximal vessel narrowing, which may lead under stress conditions to a dynamic compression of the vessel (compared to fixed stenosis in coronary artery disease). To mimic these conditions, dobutamine and volume challenge is used to invasively measure fractional flow reserve (FFR) during coronary angiography and is seen as the gold standard in assessing the hemodynamic relevance of ACAOS. We established a specialized interdisciplinary clinic for coronary artery anomalies including imaging specialists, invasive cardiologists and congenital heart disease surgeons as correct downstream testing and treatment decision is highly challenging in these patients. Thus, systematic collecting of all available diagnostic methods (invasive and non-invasive) is required to assess the optimal diagnostic procedure and treatment for these patients. Coronary computed tomography angiography (CCTA) is the method of choice to characterize the exact anatomy of ACAOS. However, how functional invasive FFR is associated with anatomical CCTA findings is unknown. Further, diagnostic accuracy of a novel independent research algorithm with computational fluid dynamics (ctFFR) as well as functional imaging (i.e. stress single photon emission computed tomography) in this specific setting is unknown. The presented project will help to understand the pathophysiology of CAAs with particular focus on ACAOS-IC and improve risk stratification based on non-invasive imaging.