Pre-operative images. (A) Three dimensional volume rendering of contrast-enhanced CT scan shows the anomalous RCA shared the same sinus with the left coronary system, with its attenuated proximal portion passing between the aorta and pulmonary trunk in patient 1. The left coronary system is patent. (B) Coronary angiogram shows anomalous origin of the right coronary artery (black arrowheads) from left sinus of Valsalva, next to the left (white arrowheads) coronary arteries in patient 2. Also it is noted that severe stenotic lesions are present on the RCA. (C) Coronary angiogram in right anterior oblique view shows collateral circulation to the distal RCA (white arrows) via septal branches of the left anterior descending artery, with the normal left coronary artery system in patient 3. (CT: computed tomography; AO: aorta; LMC: left main coronary artery; PA: pulmonary artery; RCA: right coronary artery).