QUANTIFICATION OF CAROTID-ARTERY STENOSIS WITH VARIOUS DOPPLER VELOCITY PARAMETERS

Purpose: To assess the Doppler indices best suited for detecting a ste nosis of the internal carotid artery. Material and Method: 358 patient s (234 men, 124 women, mean age 59 years, range 25-83 years) were exam ined via duplex carotid sonography (US) and arteriography. Flow indice s and B-mode real-time results of stenoses were compared with arteriog raphic findings. Results: The accuracy of US in differentiating a 50 % or more severe ICA stenosis was 93 % and the correlation coefficient between angiographic and US stenosis was 0.94. Peak systolic velocity of the internal carotid artery (vpICA) and its ratio to the systolic ( vpICA/vpCCA) and diastolic velocity of the common carotid artery were most accurate al 70 % stenosis. The vpICA/vpCCA ratio was even slightl y more accurate in cases of less severe stenosis. B-mode real-time mea surement of diameter stenosis was most accurate al the <30% level. The re was large variation in the flow values of the ICA, mostly due to th e variability of flow in the common carotid artery. The vpCCA was low in wide and higher in medium-sized or narrow common carotid arteries. Contra lateral ICA stenosis also affected the flow and thus on the vpI CA/vpCCA ratio and the differentiation between significant and non-sig nificant stenosis. Conclusions: At duplex US, B-mode real-time measure ment is suitable for screening small carotid plaques and now indices, especially vpICA and vpICA/vpCCA in severe stenoses.