Insufficiency of carotid and vertebral flow velocity in cerebrovascular disease: a continuous wave Doppler study.

In patients with cerebrovascular disease, quantitative Continuous Wave Doppler sonograms were made of carotid and vertebral arteries. In transient ischaemic attacks (TIA) all flow velocity insufficiencies were found to be related to stenosis. In stroke, however, a relatively high percentage of insufficiencies proved not to be related to stenosis. A disturbed autoregulation seems the most acceptable explanation.