Aortic nipple

Case contributed by Dr Francis Fortin



Patient Data

Age: 30 years
Gender: Female

No evidence of traumatic injury. Additional small rounded contour projecting over the aortic arch, most likely an "aortic nipple".

Annotated image shows the additional outline (blue) projecting over the aortic arch (red).

Because of a Valsalva maneuver during the image acquisition, contrast has refluxed in the venous circulation, causing particularly prominent opacification of a vein connecting the accessory hemiazygos vein to the left brachiocephalic vein. This vein is the left superior intercostal vein, which gives the radiographic image of an "aortic nipple". The azygos vein is not seen except in its arch, most likely hypoplastic with compensatory enlargement of the hemiazygos drainage system.

3D reconstruction from CT

A prominent vessel is shown lying laterally to the aortic arch and connecting the accessory hemiazygos vein (not shown) to the left brachiocephalic or innominate vein (top left of the 3D reconstruction). This represents the left superior intercostal vein, giving a radiographic appearance of an "aortic nipple".

Case Discussion

Cardiomediastinal contours should be carefully studied on all radiographs, particularly trauma patients. The aortic nipple represents a common variant of the superior mediastinal silhouette, reportedly seen on roughly 10% of chest radiographs. It represents a prominent left superior intercostal vein.

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