Intraluminal clot in the vertebrobasilar circulation: clinical and radiologic features.

We studied 15 patients with angiographically documented intraluminal clot in the vertebrobasilar (VB) circulation and ischemic stroke. Progressive brainstem signs were the most common presentation; the neurologic deficit was maximum at stroke onset in 4. Seven experienced their first symptoms during sedentary activities. Thirteen of the initial 15 CTs revealed infarcts in the VB territory, 7 with multiple foci. Intraluminal clot was present in the vertebral artery in 7 patients (2 bilateral), basilar artery in 7, posterior cerebral artery in 5, and superior cerebellar artery in 1. Multiple clots were seen in 5 patients. Stroke risk factors were present in the majority of cases. Although cardiac source embolism was the most common single etiology (4 patients), most patients had other causes including migraine, coagulopathy associated with malignancy and nephrotic syndrome in systemic lupus erythematosus, vertebral artery dissection with local embolism, delayed irradiation arteriopathy, and a fusiform, ectatic basilar artery. Six (40%) died within 5 months of follow-up. Intraluminal clot in the posterior circulation is a marker for multiple stroke mechanisms, not all of which are embolic. Intraluminal clot should prompt investigations into occult risk factors when no cause appears obvious.