Angiographically undetected ulceration of the carotid bifurcation as a cause of embolic stroke.

The accuracy of angiographic diagnosis of carotid artery ulceration was evaluated. Of those carotid bifurcations showing ulceration at surgery, 60% were diagnosed as having ulcers at angiography. Half of the remaining ulcers occurred in smooth, benign-appearing plaques and were too small to be seen at angiography. An incorrect angiographic diagnosis of ulceration was made in 17 of 50 carotid arteries; in most cases this was due to the presence of a subintimal hematoma in the wall of the artery.