CAROTID STENOSIS BY DIGITAL SUBTRACTION ANGIOGRAPHY - REPRODUCIBILITYOF THE EUROPEAN CAROTID SURGERY TRIAL AND THE NORTH-AMERICAN SYMPTOMATIC CAROTID ENDARTERECTOMY TRIAL MEASUREMENT METHODS AND VISUAL INTERPRETATION

PURPOSE: To evaluate different carotid stenosis estimation methods wit h digital subtraction angiography. METHODS: We assessed the intraobser ver reproducibility and interobserver variability of visual interpreta tion and the measurement methods used by the European Carotid Surgery Trial and the North American Symptomatic Carotid Endarterectomy Trial. Angiographic stenosis measurements according to both criteria were pe rformed twice by a radiologist, a neurologist, and a vascular surgeon. Eighty bifurcations of consecutive symptomatic patients underwent 480 pairs of measurements. In addition, four radiologists estimated the s tenoses visually. RESULTS: Intraobserver consistency was slightly bett er by the European (kappa, 0.86 to 0.94) than by the North American (k appa, 0.68 to 0.91) trial criteria or by visual interpretation (kappa, 0.79 to 0.81). No significant interobserver variability was found, ex cept in the subgroup of mild stenoses by the North American Trial crit eria. By kappa statistic, the interobserver agreement was excellent by the European trial method (kappa, 0.72 to 0.86), good by the North Am erican trial method (kappa, 0.59 to 0.77), and good to excellent by vi sual evaluation (kappa, 0.68 to 0.88). The visual estimation agreed mo re closely with the European (kappa, 0.73 to 0.92) than with the North American trial (kappa, 0.55 to 0.74) criteria measurements. CONCLUSIO NS: All three methods have good reproducibility in digital subtraction angiography. Interobserver differences become more important in the e stimation of mild stenosis.