Fig. 1.

Perimesencephalic patterns, aneurysmal patterns and basilar tip anatomy on a 3-dimensional reconstruction image of digital subtraction angiography. (A) Brain CT shows perimesencephalic pattern. Hemorrhage exists around the basal cistern with little extension to other cisterns. (B) Brain CT shows aneurysmal pattern. Hemorrhage is distributed beyond the basal cistern. (C) Bilateral superior cerebellar arteries (SCAs) originate from the basilar artery (BA) (white arrows), which shows a cranial fusion type. (D) Bilateral SCAs originate from the posterior cerebral artery (PCA) (white arrows), which shows a symmetric caudal fusion type. (E) The right SCA originates from the PCA (white arrowhead), and the left SCA originates from the BA (white arrow). This shows the asymmetric fusion type. CT, computed tomography