Variability of continuous-wave Doppler flow velocity waveform indices from the umbilical artery
Davies, J.A.; Lee, A.; Spencer, J.A.
Obstetrics and Gynecology 76(3 Part 1): 366-369
1990
ISSN/ISBN: 0029-7844 PMID: 2199867 Document Number: 359100
Using continuous-wave Doppler ultrasound, the reproducibility of umbilical artery blood flow velocity waveforms, recorded by two operators, was evaluated in 20 high-risk antenatal inpatients. Inter-operator variability was not significant for any index. The intra-operator coefficients of variation for resistance index, pulsatility index, and systolic/diastolic ratio were 7 and 7%, 12 and 12%, and 15 and 11%, respectively, for each operator. The intra-class coefficient of reliability, calculated by analysis of variance, indicated that the contribution of inter-patient variability to total variance was four times that of intra-operator variability.