The development of haemodynamics in the extracranial cerebral arteries of healthy preterm and term neonates

To investigate the development of cerebral haemodynamics in healthy preterm and term newborns, a prospective colour duplex sonography study was performed in 113 neonates at 32 to 42 weeks of postmenstrual age. In the extracranial internal carotid arteries (ICAs) and vertebral arteries (VAs), luminal diameters and angle-corrected flow velocities were measured. Flow volumes and waveform parameters were calculated. There were no side-to-side or gender-related differences for any of the parameters measured. A marked increase of luminal diameters, end-diastolic and time-averaged flow velocities and flow volumes with postmenstrual age was found in both ICA and VA (p less than or equal to 0.0001). Peak systolic velocity did not vary with age, thus, leading to a significant decrease of the resistance and pulsatility indices with rising postmenstrual age. Reference data for flow velocities, waveform parameters, luminal diameters and flow volumes of both ICA and VA are provided for different groups of postmenstrual age. In conclusion, the marked increase in cerebral blood flow volume with postmenstrual age is due to a rise in the luminal diameter of extracranial cerebral arteries and a decrease in peripheral vascular resistance. (C) 2004 World Federation for Ultrasound in Medicine Biology.