Congenital aplasia of the internal carotid artery

Case contributed by Zemar Vajuhudeen


Presenting with severe right sided headache and blurred vision. Hypertensive on arrival

Patient Data

Age: 65 years
Gender: Male

The left carotid branch arising from the aortic arch is relatively small in caliber, measuring 5 mm in diameter. At the level of bifurcation, the left internal carotid artery is not seen, suggestive of congenital absence, which is supported by an absent carotid canal. Other differentials include chronic thrombosis. Collateralisation from the left PCOM supplies the MCA territory and its branches. 

Incidental finding is noted of an intracranial aneurysm at the bifurcation of the left MCA, measuring 4 mm in size. 

The vessels of the Circle of Willis are all patent and well opacified.

Case Discussion

Incidental finding of congenital ICA absence.

The collateral circulation provided by the other arteries of the Circle of Willis compensates for the absent ICA. 

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