"Complete" duplication of the posterior cerebral artery: a rare variant detected on computed tomography angiography.

The cerebral arterial circle morphologic variability has been extensively studied. The posterior cerebral artery (PCA) variants are rarely identified, except from the first segment (P1) hypoplasia or absence. Due to its unique morphology, the computed tomography angiography (CTA) of a 34-year-old female patient was further investigated. On the right side, the typical PCA originated as the terminal branch of the basilar artery. An accessory PCA was also identified originating from the right internal carotid artery (ICA), while the right posterior communicating artery was absent. This variant corresponds to the "complete" duplication of the PCA. The left-sided PCA originated from the ICA, while the P1 was hypoplastic, representing the "partial fetal-type PCA." The rest of the cerebral arterial circle was typical. The present case of PCA "complete" duplication corresponds to a scarce variant, with a reported prevalence of 0.04%, while the fetal-type PCA is the most commonly observed variant.