The significance of internal carotid artery occlusion shown by i.v. digital subtraction angiography.

A retrospective review of 493 IV digital subtraction angiography examinations performed for cervicocerebral vascular disease revealed 27 apparent occlusions of the internal carotid artery. We identified 20 patients whose occlusions did not warrant further investigation. Fourteen occlusions were on the asymptomatic side, two were in patients who preferred medical treatment, two were in patients unsuitable for carotid endarterectomy, and two patients with bihemispheric transient ischemic attacks were treated for the contralateral carotid. Four very tight stenoses were found in the other seven patients, one of whom refused endarterectomy. As the signs of a very tight stenosis are subtle, and the number of such stenoses that are treatable is low (three in 493), cerebral angiography is justified in doubtful cases to avoid missing potentially treatable lesions.