Endocardial irregularities of the left atrial roof as seen on coronary CT angiography

Objective To describe and characterize morphological characteristics of endocardial irregularities in the roof of the left atrium as seen on coronary CT angiography. Methods We retrospectively evaluated the left atrium in 50 consecutive coronary CT patients with multiplanar reformatting, volume rendering, and virtual endoscopy. Results Twenty-one of the 50 patients had an endocardial irregularity at the roof of the left atrium. The most common finding (n = 14) was a smooth diverticulum, arising near the venoatrial junction of the right superior pulmonary vein. Conclusion Endocardial irregularities of the left atrium can be identified on coronary CT and may be more common than previously considered. The findings probably represent remnants of the cardinal venous system during embryological development. Further work should focus on the true prevalence and potential clinical significance.