Duplex scanning in extracranial vertebral artery dissection.

Ultrasonic (duplex scanning and continuous-wave Doppler) and angiographic findings in three patients with bilateral extracranial vertebral artery dissection are reported. A pattern of ultrasonic anomalies diagnostic of dissection is described, including association of a localized increase in diameter of the artery with hemodynamic signs of stenosis or occlusion at the same level and decreased pulsatility and presence of intravascular echoes in the enlarged segment.