3-DIMENSIONAL ULTRASOUND STUDY OF CAROTID ARTERIES BEFORE AND AFTER ENDARTERECTOMY - ANALYSIS OF STENOTIC LESIONS AND SURGICAL IMPACT ON THE VESSEL

Background and Purpose-It has been proved that symptomatic patients wi th severe carotid stenosis benefit from endarterectomy. Currently used methods for quantitation of the severity of carotid stenosis have lim itations, and the impact of endarterectomy on the operated region of c arotid artery remains unknown. The purpose of this study was to examin e the accuracy of a 3-D ultrasound system for quantitation of stenotic lesions and to evaluate changes in regional vessel volume and cross-s ectional area after carotid endarterectomy, Methods-We studied 14 pati ents with both carotid angiography and 3-D ultrasound, Of 13 patients who underwent surgery, 12 were reexamined with 3-D ultrasound after su rgery. The length and volume of 20 randomly selected plaques were meas ured from 3-D data sets. The severity of stenosis was quantified by 3- D ultrasound using both a diameter method and an area method on cross- sectional views at the most stenotic site; the results were then compa red with those from carotid angiography. The segmental vessel volume a nd average cross-sectional area of the operated artery both before and after endarterectomy were measured from 3-D ultrasound data. Results- Good correlation was obtained between 3-D ultrasound and carotid angio graphy in quantitative analysis of carotid stenosis (SEE=12.4%, r=0.76 , and mean difference=7.0+/-12.3% with the diameter method; SEE=10.5%, r=0.82, and mean difference=1.8+/-0.5% with the area method by 3-D ul trasound). 3-D ultrasound had excellent reproducibility and small intr aobserver and interobserver variability in plaque length and volume me asurements. No significant changes in segmental vessel volume and aver age cross-sectional area of the operated artery were observed after su rgery in patients with suture closure. However, a significant increase in segmental vessel volume was obtained in patients with polyfluoreth ylene patches applied to the surgical opening of the artery. Conclusio ns-3-D ultrasound can be used for both qualitative and quantitative an alysis of plaques in the carotid artery and to detect and quantify sig nificant carotid stenosis. Its volumetric potential has important clin ical implications in serial follow-up studies for observing the progre ssion or regression of stenotic lesions and for evaluating the outcome of interventional procedures such as endarterectomy or stent placemen t.