Opacity Pulse Propagation Measurements in Humans: Atraumatic Screening for Carotid Arterial Occlusion

Opacity pulse propagation times to areas of facial skin supplied by internal carotid (medial supraorbital area) and external carotid arteries (lateral supraorbital areas, cheeks, etc.) were carried out in 27 patients with cerebrovascular symptoms, 16 of whom had normal four-vessel angiographical studies and II of whom had unilateral carotid occlusion. In most persons with normal extracranial vessels, no significant difference is found between mean values of propagation time to internal carotid beds on the two sides of the face or between homologous areas of the face supplied by external carotid branches. With unilateral internal carotid occlusion, mean propagation time is prolonged to the medial supraorbital (internal carotid) area on the side of occlusion, while mean propagation times to external carotid beds do not differ significantly. Occlusion of the common carotid artery results in prolongation of mean propagation time to both internal and external carotid beds on the side of the arterial obstruction. Limitations of the technique and possible sources of error are discussed. The preliminary results reported suggest that this technique may be useful in atraumatic evaluation of patients for carotid arterial disease.