The development of hemodynamics in the extracranial carotid and vertebral arteries.

To investigate the development of hemodynamics in the extracranial carotid and vertebral artery system, a prospective color duplex sonography study was performed in 94 healthy children and adolescents between 3 and 18 y old. Angle-corrected flow velocities and luminal diameters were measured; waveform parameters and flow volumes were calculated. Side-to-side differences of volumetric data were analyzed. In 53 children, an intrasession test-retest flowmetry of the internal carotid and vertebral arteries was performed. From 3 to 18 y old, flow volumes decreased significantly in the vertebral arteries (p < or = 0.01) and increased in the external carotid artery (p < or = 0.0001); the luminal diameter increased in all the carotid arteries (p < or = 0.0001) and remained constant in the vertebral arteries; mean flow velocities declined in the common and internal carotid arteries and in the vertebral arteries (p < or = 0.0001), but increased in the external carotid arteries (p < or = 0.01). Flow volume rate was lower in the right than the left vertebral artery (p < or = 0.0001), and there was no side difference in any of the carotid arteries. The test-retest correlation of volumetric data was high (0.81 < or = r < or = 0.97; p < or = 0.0001). By comparing the reference data presented here with analogous adult data, we were able to delineate the physiologic development of extracranial and cerebral hemodynamics from childhood to adulthood. These data make possible the clinical application of quantitative flowmetry in extracranial cerebral arteries of children and adolescents.