VOLUME FLOW-RATES IN PATIENTS WITH CAROTI D OCCLUSIVE DISEASE - RESULTS OF ULTRASONIC TIME-DOMAIN-PROCESSING AND COLOR-M-MODE ANALYSIS

To quantify the volume flow rate- (VFR-) effects of internal carotid d isease on the common carotid artery both ipsi- and contralaterally for various degrees of stenosis. Method: A non-invasive ultrasonic time d omain processing (M-mode) was used. This proved to be reproducible in vivo and accurate in vitro. 109 patients (mean age 66.7 yrs.) having a t least 50% stenosis of the internal carotid artery or a cerebral isch aemia were studied. The haemodynamic effect of the stenosis on the ent ire anterior brain circulation supplied by the carotid artery was asse ssed. Stenoses were graded in 4 groups. Results: Significant VFR reduc tion occurred ipsilaterally in high grade (75-94%) stenosis and occlus ion of the internal carotid artery, but not with moderate (50-74%) ste nosis (p <0.05). Ipsilaterally to stenoses there was a decrease in VFR , which was more marked in higher than in lower grade stenoses. Contra laterally there was an increase in VFR. These groups differed in a sta tistically significant way (p <0.05). Conclusion: This ultrasonic VFR method demonstrates the flow effect of carotid stenoses both ipsi- and contralaterally and adds to the understanding of the haemodynamics in individual patients.