Objective: The purpose of this study was to compare the abilities of color-coded duplex sonography, CT angiography, and selective digital subtraction angiography to reveal disease requiring surgery in patients with occlusive disease of the carotid bifurcation.
Materials and methods: Fifty-six carotid arteries in 28 patients who had 48 carotid stenoses and symptomatic cerebrovascular disease were prospectively studied by selective digital subtraction angiography, color-coded duplex sonography, and CT angiography. CT data were displayed in maximum intensity projection. The degree of stenoses revealed were graded as mild, moderate, severe, and occluded according to North American Symptomatic Carotid Endarterectomy Trial criteria. The results of CT angiography and color-coded duplex sonography were correlated with the gold standard of digital subtraction angiography.
Results: Grading of stenoses on CT angiography agreed with grading of stenoses on digital subtraction angiography in 89% of cases. All high-grade stenoses and occlusions revealed on CT angiography were correctly interpreted by all observers. For stenoses revealed by color-coded duplex sonography and digital subtraction angiography, observers' agreement was 75%. Two severe stenoses were incorrectly graded as occluded by the interpreter of the color-coded duplex sonograms. Also, one occluded carotid artery was misdiagnosed as moderate stenosis.
Conclusion: Our results indicate that CT angiography is superior to color-coded duplex sonography for evaluating carotid disease and determining disease requiring surgery. CT angiography warrants further investigation in a larger group of patients.