Color-coded Doppler imaging of normal vertebral arteries.

Using color-coded Doppler sonography, we studied the vertebral arteries of 42 persons without history or physical signs of vertebrobasilar disease. The intertransverse portion of the vertebral artery was visualized in all persons on both sides. Its origin was visualized in 37 persons (88.1%) on the right side and in 28 (66.7%) on the left; the atlas loop was visualized in 32 persons (76.2%) on the right side and in 36 (85.7%) on the left. Four vertebral arteries were hypoplastic. Peak systolic blood velocity ranged from 19 to 98 (mean 56) cm/sec and peak diastolic blood velocity ranged from 6 to 30 (mean 17) cm/sec. Resistive indices ranged from 0.62 to 0.75 (mean 0.69). Thus, color-coded Doppler sonography seems to be a promising noninvasive method for the evaluation of hemodynamics in the extracranial portion of the vertebral arteries.