Accuracy of color-Doppler in the quantification of proximal vertebral artery stenoses

Vertebrobasilar (VB) strokes appear to have the same causes as carotid strokes. Obstructive lesions of proximal vertebral arteries probably occur in about 30% of stroke patients.

Our aim was to assess the validity of color Doppler sonography compared to selective intra-arterial angiography in the quantification of proximal vertebral artery stenoses.

A prospective blind study of 316 vertebral arteries was undertaken between 1996 and 1998. One hundred and fifty-eight patients with cerebrovascular disorders without cerebral hemorrhage were studied consecutively by frequency or amplitude color Doppler flow imaging and intra-arterial angiography. The lesions were quantified by morphological and hemodynamic criteria and classified into 6 groups: 0% 207 arteries; 1-29% 32 arteries; 30-49% 29 arteries; 50-69% 13 arteries; 70-99% 23 arteries; 100% 12 arteries.

Ten of the 12 occlusions were identified, the 2 false-negatives were due to 2 revascularized vessels. Moderate stenoses (<50%) were differentiated from tight stenoses (>50%) using hemodynamic criteria. The majority of false-negative stenoses (38) in the different groups were related to intrathoracic or very deep origin of the artery, anechogenic stenosis or a tortuous vessel. Stenoses greater than 70% were diagnosed in 71% of cases with a specificity of 99%. The kappa value was 0.80.

Duplex sonography should be proposed first in VB attacks or stroke to detect and quantify vertebral artery stenoses for surgery and angioplasty.