Anatomic variations and anomalies of the coronary arteries: 64-slice CT angiographic appearance

PURPOSE To retrospectively review the 64-slice computed tomography (CT) appearance of coronary artery anatomic variants and anomalies and determine their incidence in 700 patients. MATERIALS AND METHODS CT data of 700 patients who underwent 64-slice CT angiography (CTA) because of known or suspected coronary artery disease were retrospectively reviewed by two radiologists experienced in cardiovascular radiology. In each study, anatomic variants and anomalies were investigated. RESULTS The coronary artery system was right dominant in 76%, left dominant in 9.1% and co-dominant in 14.8% of the cases. Ramus intermedius was present in 31%. Conus artery with a separate ostium in the right sinus Valsalva was observed in 22%, and in 0.2% two conus arteries originating with separate ostia were visualized. The sinus node artery (SNA) originated from the right coronary artery (RCA) in 79%, from the circumflex artery (Cx) in 20%, and from the left main coronary artery (LMCA) in 0.4%. In 0.4% of the cases SNA originating from the right sinus Valsalva with a separate ostium was seen. LMCA was absent in 0.4%. Cx was absent in 0.1%, and diagonals were absent in 0.1%. High takeoff of LMCA and RCA were observed in 0.7% and 0.1%, respectively. Myocardial bridging was observed in 37%. Anomalous origin of the coronary artery from the opposite sinus was observed in 1% of the cases. CONCLUSION Complex anatomy of the coronary artery system can accurately be depicted by 64-slice CTA. This modality is useful in detecting coronary artery variants and anomalies and is a valid alternative to conventional coronary angiography in their diagnosis.