BACKGROUND: Anomalous coronary arteries (ACAs) may present increased risk for adverse cardiac events. We sought to evaluate the accuracy of conventional coronary angiography (CCA), as it is currently used in clinical practice, compared with expert interpretation and cardiac magnetic resonance imaging (CMR) in determining the site of origin and proximal course of ACAs. METHODS: Fifty consecutive patients without concomitant congenital heart disease, who were referred for CMR to diagnose the course of an ACA, were retrospectively evaluated. Original CCA reports were reviewed. Angiography images were available in all patients and were interpreted by 2 experts blinded to the prior interpretation and CMR results. The accuracy of interpretation in each group was then compared to the current gold standard of CMR. RESULTS: Identification of the site of origin (ie, aortic sinus) by referring angiographers was similar to that of expert angiographers (sensitivity, 89% vs 98%, respectively; P=.10). However, referring angiographers were less likely to correctly identify the proximal course as compared with expert angiographers (sensitivity, 27% vs 98%, respectively; P<.001). CONCLUSIONS: As it is used in current practice, CCA does not provide sufficient diagnostic accuracy for identifying the proximal course of an ACA. Review by expert angiographers added sensitivity, improving the accuracy to nearly 100%. Expert consultation may be nearly as accurate as advanced imaging, and should be considered in cases of ACA in which there is diagnostic uncertainty.