Color-coded duplex ultrasonography of the origin of the vertebral artery: Normal values of flow velocities

The introduction of color-coded duplex ultrasonography has improved the eas e of performing ultrasound investigations of the vertebral arteries. So far , normal values of flow velocities have been reported only for the intertra nsverse region of the vertebral artery (V2 segments). Atherosclerotic disea se at the origin of the vertebral arteries (V0 segment) is frequent and is one of the risk factors for vertebrobasilar ischemic disease. Normal values of flow velocities of the vertebral artery origin are needed to assess pat hologic findings, such as vertebral artery origin stenosis or dissection. T he aim of this study was to describe the normal flow velocities of vertebra l artery origin (V0 segment) and the pre- (V1 segment) and intertransverse (V2 segment) part in 50 age-matched neurologic patients (mean age 54) witho ut ischemic cerebral disease. The V0 segment could be visualized in 46 pers ons (92%) on the right side and in 43 (86%) on the left. The peak systolic blood velocity ranged from 30 to 100 cm/s (mean 63.6 +/- 17.5 cm/s), and en d-diastolic blood velocity ranged from 10 to 35 cm/s (mean 16.1 +/- 5.1 cm/ s). Analysis of side-to-side differences showed no significant differences of flow velocities in all subjects. It is concluded that color duplex ultra sonography is a feasible method to insonate the origin of the vertebral art ery, and that nomogram data could be established. It is suggested that colo r-coded duplex ultrasonography of the vertebral artery origin should be per formed in all patients with clinical symptoms or signs of vertebrobasilar i schemic disease. Nevertheless, further studies are needed to determine the normal and pathologic values of flow velocities of the vertebral artery ori gin and their reproducibility.