Ultrasonic duplex scanning of the prevertebral segment of the vertebral artery in patients with cerebral atherosclerosis.

A routine duplex investigation of the prevertebral segment of the vertebral artery was carried out in 2814 consecutive patients who were suspected for extracranial cerebral atherosclerosis. Depending on local anatomical properties duplex scanning failed to make a decision about the state of the ostium of the vertebral artery in 24% of the cases. This occurred in approximately three quarters of the cases on the left side. With regard to the state of the ostium of the vertebral artery, we compared the data of duplex scanning with those of intra-arterial contrast angiography in 211 patients. For the detection of a stenosis with a diameter reduction of 50% or more at the site of the ostium, duplex scanning has respectively a sensitivity of 0.80, a specificity of 0.92, a positive predictive value of 0.73, and a negative predictive value of 0.94. Eighty-seven percent of the occluded vertebral arteries were correctly identified. In some patients with severe multi-vessel disease, a high-flow or a low-flow state of the vertebral artery or a subclavian steal syndrome did not allow a correct decision with the duplex scanner about the state of the ostium of the vertebral artery. Significant atherosclerotic lesions of the remaining part of the prevertebral segment of the vertebral artery were rare. However, this study shows that duplex scanning of this segment is very well possible and in most cases the results of the non-invasive test were in accordance with those of arteriography.