Azygos and hemiazygos veins

Case contributed by Chris O'Donnell
Diagnosis certain


Assessment for aortic dissection. Bicuspid aortic valve and chest pain.

Patient Data

Age: 40 years
Gender: Male

Beautiful retrograde filling of azygos and hemiazygos veins via a right cubital fossa intravenous 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 mediastinum.

Case Discussion

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

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