Presentation
The patient came with a persistent headache and normal motor and sensory function.
Patient Data
There is evidence of hypoplasia of the right internal carotid artery from its origin with small right carotid canal diameter in comparison with the contralateral side and prominent right posterior communicating artery.
The left posterior communicating artery is prominent and left segment P1 of left PCA appear hypoplastic.
There is evidence of hypoplasia of the right internal carotid artery from its origin with small right carotid canal diameter in comparison with the contralateral side and prominent right posterior communicating artery.
The left posterior communicating artery is prominent and left segment P1 of left PCA appear hypoplastic.
Annotated images for clarification of the findings.
On 3D images, the arrows point the site of the right internal carotid artery and fetal posterior communicating posterior cerebral artery.
Case Discussion
Congenital absence of the internal carotid artery (ICA) is a rare anomaly that occurs in less than 0.01% of the population. It encompasses agenesis, aplasia, and hypoplasia.
The diameter of the right carotid canal is smaller than the contralateral side which supports the diagnosis.
Collateral flow through the circle of Willis mainly from the right posterior communicating artery, as in this case, is the most common type.
A left fetal communicating posterior cerebral artery is noted (normal variant).