A 47 year-old man developed the abrupt onset of a left hemiparesis.

(Left) Right Carotid Angiogram at the level of the carotid bifurcation; (Middle) Right Carotid Angiogram at the level of the base of the skull; (Right) Axial CT 3 days later. Note on the angiogram the abrupt tapering and occlusion of the internal carotid artery. This is one of the classic appearances of a dissection. Following successful stenting and TPA, circulation was re-established to the distal carotid. Note that the artery remains tapered in addition to the presence of an aneurysm sac is the carotid wall. On the CT scan, a hypodensity is seen in the distribution of the right middle cerebral artery, resulting from an artery to artery embolus from the dissection. However, without successful opening of the vessel, the size of the stroke would have been much larger and potentially fatal.