The aim of this study was to investigate CT angiography (CTA)
luminal area measurements in the assessment of
carotid artery stenosis compared with the current clinically used criteria based on lumen diameter measurements. Seventy-two vessels in 36 patients were evaluated by CTA and digital subtraction angiography (DSA). Two observers measured area and diameter
stenosis degrees using automated 3D CTA analysis software. The ratio of the largest/smallest
luminal diameter at the level of maximal
stenosis (L/S ratio) was used to describe lumen morphology. Diagnostic agreement between CTA and DSA was calculated. For the assessment of area
stenosis, interobserver and intraobserver correlation coefficients were 0.898 and 0.906 (p<0.001). The correlation coefficient between the diameter
stenosis and area
stenosis was lower in
stenoses with extremely noncircular lumen (L/S ratio>or=1.5) (r=0.797, p<0.001) compared with
stenoses with circular lumen (LS ratio<1.2) (r=0.978, p<0.001). Only satisfactory agreement (kappa 0.54-0.77, p<0.001) was obtained between area
stenosis on CTA and diameter
stenosis on DSA. Assessment of
stenosis degree with area measurements on 3D CTA proved to be reproducible. Area
stenosis provides a less-severe estimate of the degree of
carotid stenosis but might theoretically express the real hemodynamic significance of the lesion better than diameter
stenosis, especially in
stenoses with noncircular lumen.