Absence of the left brachiocephalic vein with venous return through the left superior intercostal vein: CT findings.

Asymptomatic congenital thoracic venous anomalies are becoming clinically more relevant with the increasing utilization of minimally invasive surgical vascular procedures, such as left-sided implantable cardioverter defibrillator implantation. The purpose of this report is to describe the computed tomography findings of the congenital absence of the left brachiocephalic vein in a patient with no evidence of congenital cardiovascular disease and no prior history of central venous instrumentation. In this patient, the left internal jugular and the left subclavian veins drain via the left superior intercostal vein, the accessory hemiazygous, the hemiazygous, and the azygous vein into the right brachiocephalic vein to form the superior vena cava. The clinical significance and possible embryogenesis of this anomaly are discussed.