Value of transoral carotid ultrasonography in detecting the change of distal extracranial internal carotid artery with stenosis and occlusion in its initial segment

Abstract

Objective To investigate the value of transoral carotid ultrasonography (TOCU) in detecting the change of distal extracranial internal carotid artery(ICA) with stenosis and occlusion in its initial segmen.Methods One hundred and ten patients with stenosis at least 50％ or occlusion in the initial segment of ICA diagnosed by high-frequency linear probe were enrolled as case group,while thirty two with healthy carotid arteries as control group.Both of the case and control groups were undergone high-frequency linear probe to examine CCA and the initial segment of ICA,and TOCU to observe their lumen transparency,color Doppler flow display and change of Doppler flow spectrum,even measuring the internal diameter,peak systolic velocity (PSV),end-diastolic velocity(EDV) and PSVICA/PSVCCA ratio,respectively.Digital subtraction angiography (DSA)were performed within two weeks,then compared with ultrasonography.Results 92.7％ patients were performed TOCU examination in case group and 93.8％ in control group.The internal diameter and PSV of the distal extracranial ICA became gradually smaller from control group to near occlusion group,and there were statistical significance between groups ( P ＜0.05),however,near occlusion group had no statistical significance compared with occlusion group( P ＞0.05).There were 80％ arteries having thrombus echo in occlusion group,and the others in this group having no thrombus had gloomy colour flow,even got low-velocity artery spectrum.Doppler flow spectrum of distal extracranial ICA showed characteristics of slow wave or single peak in near occlusion group,and spike shape or slow wave in 76.7 ％ arteries of 70％ ～near-occlusion stenosis group,but spike shape in 30.8％ arteries of 50％～69％ stenosis group,and the others were normal.Conclusions TOCU is useful for detecting the changing regularity of distal extracranial ICA with stenosis or occlusion in its initial segment and has the value of clinical application in association with high-frequency linear probe. Key words: Endosonography; Carotid stenosis; Hemodynamic phenomena