Internal carotid artery occlusion diagnosed by Doppler ultrasound.

Internal Carotid Artery Occlusion Diagnosed by Doppler Ultrasound • Using a transcutaneous Doppler ultrasonic blood velocity detector, retrograde ophthalmic artery blood flow was demonstrated in four patients, all of whom had angiographically confirmed occluded internal carotid arteries. In three, compression of the facial artery obliterated the ophthalmic artery signal. In a fourth patient compression of the superficial temporal artery produced the same result. The technique presently used to monitor ophthalmic artery blood flow and to detect retrograde ophthalmic flow is described. This simple method appears to be at least as useful as ophthalmodynamometry in the routine evaluation of patients for extracranial occlusive disease, is easier to perform, and has a wider range of application. ADDITIONAL KEY WORDS ophthalmic artery collateral blood flow blood velocity cerebral angiography ophthalmodynamometry • The Doppler ultrasonic blood velocity detector was first used clinically to localize transcutaneously the precise site of vascular occlusion in peripheral arteries. 1 Because of the relationship of extracranial carotid occlu-sion to strokes, it seemed that this atraumatic diagnostic method might also be used to evaluate these patients. Brinker, Landiss and Croley, 2 and Gross-man and Wood, 8 while recording directly from the carotid vessels, found recognizable changes in the frequency of the Doppler signal in patients with carotid occlusion. We, and others, 4 however, have not found direct recording over the carotid artery in the neck reliable. With our equipment, we could not identify the carotid bifurcation, distinguish internal from external carotid blood flow, or localize angiographically demonstrated complete or partial carotid occlusions. Recently, we have demonstrated that by comparing the relative velocity of blood flow through the ophthalmic arteries, valuable 122 clinical information could be obtained in patients with carotid artery occlusion, carotid cavernous sinus fistula, ophthalmic artery thrombosis and intraorbital tumor. 5 Our preliminary laboratory and clinical experience with surgical or disease-induced acute occlusion of the internal or common carotid artery suggested that this diagnostic procedure, termed ophthalmosonometry (OSM), was a safe and simple method for evaluating patients for extracranial carotid occlusion. However, a few patients with angiographically complete occlusion of the internal carotid artery had no demonstrable OSM changes in the ipsilateral ophthalmic artery blood flow. In these patients, a well-developed collateral circulation between the external carotid and the ophthalmic artery was angiographically demonstrated. Since the direction of blood flow cannot be determined with this technique, collateral circulation severely limited the clinical application of this procedure. We subsequently …