Flow velocity and flow volume measurements in the extracranial carotid and vertebral arteries in healthy adults: reference data and the effects of age.

To establish reference data and to investigate the development of haemodynamics in the extracranial carotid and vertebral arteries, we performed a prospective study in 78 age- and gender-matched healthy adults from 20 to 85 y old. Angle-corrected flow velocities and luminal diameters were measured and waveform parameters and flow volumes calculated in all the arteries. Side-to-side differences and the influence of age on these parameters were also investigated. In the common carotid arteries, the internal carotid arteries and the vertebral arteries (CCA, ICA and VA, respectively) all flow velocities decreased significantly during ageing. The luminal diameter remained constant in all the carotid arteries, but increased slightly with age in the VA. An age-related decline of intravascular flow volume was observed in the ICA. Due to a pronounced decrease in end-diastolic flow velocity, the resistance index decreased in ICA and VA during ageing. There were no significant side-to-side differences in flow velocities and flow volumes in any of the extracranial arteries. The luminal diameters of the CCA, ICA and ECA were significantly smaller in women than in men. No relevant gender-related differences in flow velocities or waveform parameters were found in the extracranial arteries. There was no gender-linked difference in the flow volumes of the brain-feeding arteries and, in the ECA, flow volumes were significantly higher in men. Reference data on all flow velocities and waveform parameters, luminal diameters and flow volumes were established for different age groups between 20 and 85 y old. These data allow us to outline the development of cerebral haemodynamics during "benign ageing" and to utilise flow volume measurements in clinical practice, especially in patients with cerebrovascular diseases.