Fig 2. Angiographic assessment of the patients. This diagram shows schematic representations of the circle of Willis and the major intracranial vessels in each patient. Black lesions indicate the location of the stenosis or occlusion. Acom indicates the anterior communicating artery; Pcom, the posterior communicating artery; Rt; right, Lt; left; M1-M3, collaterals reconstituting the M1, M2, or M3 segments; None, little or no significant reconstitution of the territory of the occluded vessel.