Evaluation by colour Doppler and pulsed Doppler sonography of blood flow velocities in intracranial arteries during the early neonatal period.

Using a colour pulsed Doppler flow mapping system, we examined the intracranial arteries of 40 healthy infants. The anterior cerebral, basilar, intracranial internal carotid and middle cerebral arteries were visualized clearly enough to evaluate flow velocity at the success rates of 100%, 87.5%, 65% and 82.4%, respectively. In the anterior cerebral, intracranial internal carotid and middle cerebral arteries, the maximum blood flow velocity slightly decreased to a minimum at around 4-6 h after birth, and then gradually increased. The minimum blood flow velocity pattern was similar. The maximum blood flow velocity in the basilar artery decreased from 0-3 h, rapidly increased from 4-6 h, and remained at a steady level thereafter. A possible mechanism for the chronological changes in the intracranial blood flow velocity is discussed.