Figure 1

Acute vertebrobasilar territory stroke following percutaneous thromboaspiration of an occluded arteriovenous fistula of the forearm. (A) Magnetic resonance imaging (MRI) of the head. Serial 5 mm axial brain images show the presence of bilateral hypersignal areas (indicated by arrowheads) in the cerebellar hemispheres and bulboprotuberancial junction. (B) Hypersignal in the thalamic areas, predominantly on the left. (C) Hypersignal in the occipital lobe. (D) Polygon of Willis by MRI time of flight show bilateral occlusion of the posterior cerebral arteries. (E) Polygon configuration of Willis in our patient. The arrows show the localization of bilateral occlusion of the Posterior cerebral arteries (PcoA, posterior communicating artery; PCA, posterior cerebral artery (P1 and P2 indicate the PCA segments); ACA, anterior cerebral artery (A1+A2 indicate the ACA segments); MCA, middle cerebral artery; ICA, internal carotid artery; BA, basilar artery; VA, vertebral artery. Note that our patient displays a "fetal type" right PCoA, in that the P1 segment is hypoplastic and the ICA supplies right posterior cerebral territory via PCoA.