Acceleration time in cerebral arteries of preterm and term infants

We measured the acceleration times in the pericallosal, internal carotid, and basilar arteries with two-dimensional/pulsed Doppler ultrasonography in 145 nondistressed preterm and term infants between 24 and 48 hours after birth. In all three arteries we found a linear relationship between the acceleration time and menstrual age or birth weight. These findings were determined by changes in peak systolic flow velocity, but not by changes in mean arterial blood pressure or cardiac output. We speculate on an important role for cerebral autoregulation in the acceleration time variations between newborn infants of differing menstrual ages and birth weights.