A single coronary artery is a rare congenital anomaly (less than 1% on CT angiography) where only one coronary artery arises from the aortic trunk. Lipton et al. divided it into two main types: right (R) and left (L), describing the single coronary artery as it originates from the right or left coronary sinus. Unlike other classification types where coronary perfusion may be compromised, the R1 or L1 classification usually has a benign clinical course.

Case submitted by Neil Eric L. Pecache, MD, Rainier John S. Buensalida, MD, and Simonette T. Sawit, MD.