[Doppler sonographic measurement of normal values of flow velocities in the internal carotid artery of premature infants, newborn infants and infants].

In 121 healthy premature born infants, full-term newborns and older infants (gestational age: 29 to 45 weeks; weight at investigation: 1070 g to 3750 g), the flow velocities in the internal carotid arteries were measured by pulsed doppler sonography. All infants were investigated by computer sonography (Acuson 128) with a 5 MHz transducer. The following parameters were measured: The maximal systolic velocity, the end-systolic and end-diastolic velocity as well as the mean flow velocities, the pulsatility-index and the resistance-index. For all parameters the relationship to the gestational age and weight were analysed. All flow velocities increased linearly with increasing gestational age and weight. In contrast to the flow velocities neither the pulsatility-index nor the resistance-index changed with increasing gestational age and weight. As flow velocities in the internal carotid arteries increase with increasing gestational age and weight these parameters must be taken into consideration when pathologic flow velocities are analysed.