Transient ischemic attacks with external carotid artery stenosis and a normal internal carotid artery

Transient ischemic attacks have been attributed to emboli from the external carotid artery in patients with complete occlusion of the internal carotid artery. We report a patient with an external carotid stenosis and normal internal carotid who developed ipsilateral transient ischemic attacks. Real time B-mode ultrasonography demonstrated that the plaque obstructing the external carotid artery extended into the carotid sinus. This may have served as a source of emboli into the internal carotid circulation.