Azygos venous system anatomy (CT pulmonary angiography)

Case contributed by Henry Knipe
Diagnosis not applicable


Pleuritic chest pain for days ?PE.

Patient Data

Age: 35 years
Gender: Male

No pulmonary embolus. 

Contrast is seen to reflux in the azygos system including the left supreme intercostal vein, azygos vein, hemiazygos vein and accessory hemiazygos vein. This was thought to occur because the patient started to strain during the scan, increasing intra-abdominal pressure. 

Case Discussion

Unusual reflux of contrast into the azygos system, highlighting its anatomy on the CTPA study. 

This case has a common configuration of a common trunk of the hemiazygos and accessory hemiazygos draining into the azygos vein. It also demonstrates the extensive communication with the vertebral venous plexus as well as the communication between the accessory hemiazygos and the left superior intercostal vein (which is more common than no communication). 

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