Exclusive contra lateral irrigation of the anterior cerebral artery territory through the anterior communicating artery: an angiographic verification – case report

Anatomical variations in the circle of Willis are every day findings in neurosurgical and neurointerventional procedures. A clear understanding of these variants is important since they could have serious clinical consequences if not considered properly. In a carotid angioplasty and stenting (CAS) we found a bilateral angiographic variation of the feeding of the anterior cerebral artery (ACA) territory by an unusual anteriorcommunicating artery (ACoA). Our first impression was that a fragment of the atherosclerotic plaque occluded the ACA, but the patient did not show any neurological deficit. After evaluation of the contra lateral common carotid artery (CCA) we realized that we were facing an uncommon angiographic variation of the ACoA.These kind of anomalies must be recognized during a functional cerebral angiography in order to evaluate hemispheric collateral flow properly and to understand paradoxical clinical manifestations of occlusive diseases.