Evaluation of arterial and venous variations in thorax computed tomography examinations.

Vascular variations may be found incidentally during radiological imaging and may not cause any symptoms throughout life. This study was carried out to determine the incidence and clinical significance of normal, variable and abnormal branching patterns of thoracic vascular structures in the general adult population using computed tomography (CT) images. Thorax CT images of 1510 patients (716 males and 794 females) aged between 18 and 95 years were reviewed for this purpose. One hundred and eighty-four (12.2%) patients had bovine arch variation in which the brachiocephalic trunk and the left common carotid artery originated from a common source. In 57 (3.8%) of the examined cases, the left vertebral artery was observed to directly originate from the aortic arch. Additionally, in 14 (0.9%) patients, the right subclavian artery was found to arise directly from the aortic arch. The accessory hemiazygos vein drained into the left brachiocephalic vein in 329 (21.8%) patients, and the right internal thoracic vein opened into the superior vena cava in 29 (1.9%) patients. Azygos vein variation was detected in 18 (1.2%) patients among the examined 1510 patients. Among 1510 patients analysed, double superior vena cava was found in one female patient, and situs inversus totalis was found in two female patients. Knowledge about these variations is important during interventional procedures. CT is a non-invasive imaging modality that offers a comprehensive assessment of these variations.