Azygos and hemiazygos veins

Beautiful retrograde filling of azygos and hemiazygos veins via a right cubital fossa intra-venousintravenous injection of radiographic contrast. Azygos vein rejoins the SVC in the chest and arises from the IVC posteriorly at the level of the right renal vein. The hemiazygos vein arises from a lumbar vein in the upper lumbar region and joins the azygos in the mid posterior medistinummediastinum.

Azygos veins do not usually fill so dramatically on CT chest but in this case, the large volume of contrast used (150mls(150 mL) and high injection rate of 5ml/sec5 mL/s (in order to produce a dense aortogram) has led to contrast reflux into the azygos vein via the SVC.