Anomalous internal carotid anastomosis to contralateral anterior cerebral artery.

ABSTRACT

BACKGROUND: Many anomalies and variants in vascular anatomy have been reported in relation to the anterior cerebral artery (ACA). PATIENTS AND METHODS: We encountered an apparently novel anomaly in a 30-year-old man admitted for disturbance of consciousness following a traffic accident. Computed tomography revealed an acute subdural hematoma and subarachnoid hemorrhage. RESULTS AND CONCLUSIONS: No vascular abnormalities related to the hemorrhage were detected by conventional angiography, so we concluded that the bleeding was of traumatic origin. Anomalous origin of the ACA was disclosed incidentally, with both A1 segments arising from the right internal carotid artery; no normal A1 segment of the left ACA was visualized. We discuss possible bases for this anomalous origin.