Journal of Ultrasound in Medicine, Vol 7, Issue 10 549-551, Copyright © 1988 by American Institute of Ultrasound in Medicine
Comparison of umbilical artery flow velocity waveform indices as measured by continuous wave Doppler ultrasound
W. M. Gilbert, K. H. Nicolaides, T. Sel and S. Campbell
Harris-Birthright Research Centre for Fetal Medicine, Department of Obstetrics and Gynaecology, King's College Hospital, London, UK.
This study examines four methods, automated and manual, of calculating the
pulsatility index (PI) of fetal umbilical artery flow velocity waveforms
(FVW) and compares these values to the resistance index (RI), the A/B
ratio, and the degree of absence of end diastolic frequencies. The FVWs
were obtained by the Doptek continuous wave Doppler ultrasound. All of the
maximum envelope indices had significant correlations; a highly significant
difference was found between the automated and the manual methods of
determining PI. When PI was measured manually, there was a better
correlation between the A/B ratio, RI, and degree of absence of end
diastolic frequencies than when the automated methods were used.
