Caption: (A) Unenhanced CT cerebral angiogram showing a hyperdense basilar artery (white arrow) with no established infarction. (B) Contrast-enhanced CT angiogram confirmed a proximal basilar occlusion (white arrow) with patency of the mid to distal third; there was a large-calibre right posterior communicating artery that presumably provided collateral supply to the posterior circulation. (C) 3D reconstruction (posterior view) showed the extent of occlusion (broken red line). (D) digital subtraction angiogram identified a proximal basilar artery occlusion (white arrow) with little flow in the intradural vertebral artery. (E) A residual stenosis with thrombosis (white arrow) remained after vacuum aspiration. The vessel patency improved after stent retrieval. (F) At the end of the procedure, there was a non-flow limiting residual stenosis; this probably represented arteriosclerotic disease but we could not exclude local dissection. 3D, three dimensions (see Grundy D, et al. page 82).