Reproducibility of measurement of pulsatility index by Doppler ultrasound of the anterior cerebral artery of preterm infants.

Ten preterm infants were each studied by three observers using a commercial duplex Doppler ultrasound scanner, in order to determine the intra-observer and inter-observer variability in the measurement of pulsatility index (PI) of the anterior cerebral artery. There was considerable difference in estimates of PI, with a mean range of 0.11 between the three observers for each infant. Intra-observer variability exceeded inter-observer variability and had a coefficient of variation of 8.4%. The five observers involved in this study had less than six months experience of duplex scanning. The results suggest that the PI can be measured with acceptable reproducibility by personnel with limited experience.