We describe a misleading case of a partially occluded A1 segment duplication that mimicked an ACoA aneurysm on computed tomography angiography and conventional angiography and led to surgical intervention. The location of such an anomaly at the ACoA on the side of least hemodynamic stress may provide a clue to recognizing this variant.
Department of Surgery, Division of Neurosurgery, Department of Radiology, Centre Hospitalier de l'Université de Montréal (CHUM), Hôpital Notre-Dame, Montreal, QC, Canada.
