Comparison of degree of stenosis and plaque volume for the assessment of carotid atherosclerosis using 2-D ultrasound.

The degree of carotid stenosis (%ST) remains the most frequently used parameter for identifying patients with high risk of stroke but the relationship between %ST and the occurrence of stroke remains controversial. The objectives of this study were to check (1) the relationship between the %ST and the plaque volume index (PVI) as measured by echography and Doppler, (2) the relationship between the intima media thickness (IMT), a vessel wall remodeling index and the PVI an atheromatous growth index. For each of the 128 patients, (165 carotid stenosis), we measured the % ST (section or diameter), the max stenosis velocity (V(max)), the PVI and the common carotid IMT. The %ST (section) ranged from 10% to 93% (mean 66+/-18), V(max) from 0.3m/s to 3m/s (mean 1.2+/-0.8), PVI from 0.61cm(3) to 1.17cm(3) (mean 0.41+/-0.21) and the IMT from 0.08cm up to 0.31cm (mean 0.12+/-0.03). There was no significant correlation between either PVI and %ST (section or diameter), PVI and minimal stenosis section area (S1) or between PVI and V(max). There was no significant correlation between IMT and both %ST area and PVI. PVI was significantly correlated with the whole artery section area (S2) and the plaque length (L). The %ST (section or diameter) was significantly correlated with S1 but not with S2. The absence of correlation between the PVI and the %ST confirm that these two parameters describe two different processes of the atheromatous development.