The prevalence of coronary artery variations on coronary computed tomography angiography

Background: Coronary computed tomography angiography (CCTA) can delineate the coronary artery anatomy precisely. Basic knowledge of the normal coronary artery anatomy and familiarity with its common variations are essential in order to assess CCTA accurately. Purpose: To determine the prevalence of coronary artery variations detected by 64-slice mutidetector CT. Material and Methods: CCTA images of 2096 patients were evaluated retrospectively. Relatively unusual coronary artery morphological features that were seen in greater than 1% of the study population were classified as variations. Results: Coronary artery circulation was right dominant in 86.6%, left dominant in 9.6%, and balanced in 3.8% of patients. The conus artery arose from the right coronary artery in 83%, or directly from the aorta with a separate ostium in 17% of cases which was much more common in men than women. The sinoatrial node artery originated from the right coronary artery (65.6%) or the circumflex artery (33.7%). The atrioventricular node artery originated from the right coronary artery in 86.4% or the circumflex artery in 13.6% of cases. The left main coronary artery was shorter than 0.5 cm in 4.7% of cases and trifurcated into the intermediate artery in 31.3% of cases. A myocardial bridge was observed in 21.6%, coronary ectasia-aneurysm in 2%, dual left anterior descending artery (LAD) type 1 in 1.38%, and a variant of type 1 in 0.1% of cases. The presence of coronary atherosclerosis was higher in patients with coronary ectasia-aneurysm than the patients who did not have coronary ectasia-aneurysm (90.5% vs. 72.2%, P = 0.000). Conclusion: CCTA is a non-invasive imaging modality for the depiction of variations of the coronary arteries. The incidence of coronary artery variations is high and various, and readers should be familiar and looking for these conditions during interpretation of CCTA examinations.