Quantitative common carotid artery blood flow: prediction of internal carotid artery stenosis.

Common carotid artery (CCA) blood flow was measured noninvasively with a pulsed Doppler duplex scanner modeled after the Octoson (Ultrasonics, Inc., No. Yonkers, N.Y.). The aim of the study was to determine normal values and to assess the accuracy of CCA flow as a predictor of internal carotid artery (ICA) stenosis. One hundred one people who did not have disease were studied; the overall mean flow rate was 395 +/- 79 ml/min (mean +/- S.D.). There was no significant correlation with age, height, or body surface area but there was with body weight (p less than 0.05). A statistically significant difference was evident between men (424 +/- 88 ml/min) and women (371 +/- 62 ml/min) (p less than 0.001). The intrasessional variation (S.D./mean) was 13% and the intersessional variation, 16%. No significant difference was seen between the sides. Ninety-two patients who had carotid angiography were studied and the flow rates compared with the degree of ICA stenosis on each side. The flow rate for mild ICA stenosis (1% to 39%) was 404 +/- 109 ml/min, for moderate stenoses (40% to 69%), 390 +/- 91 ml/min, and for severe stenoses (70% to 99%), 351 +/- 109 ml/min. There was a significant difference in flows only between mild and severe grades of stenosis of the ICA (p less than 0.01). With unilateral stenosis, comparison of flow values in the normal and affected sides showed the greatest discriminatory power when the absolute difference of flow values was taken (p less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)