INTRAOBSERVER VARIABILITY OF PULSATILITY INDEX MEASUREMENTS IN 3 FETAL VESSELS IN THE FIRST-TRIMESTER

Purpose. The intraobserver repeatability of pulsatility index measurem ents in 3 fetal vessels in the early weeks of gestation was evaluated. Methods. The pulsatility index was calculated from the flow velocity waveforms from 3 fetal vessels in a series of 58 uneventful, low-risk, singleton first-trimester pregnancies using transvaginal color Dopple r sonography. The intraobserver repeatability was expressed as the int raclass correlation coefficient. Mean menstrual age at the lime of the examination was 10.3 weeks (range, 7.6-13). Results. Flow velocity wa veforms from the umbilical artery, abdominal aorta, and middle cerebra l artery were obtained in 100% (58/58), 98.3% (57/58), and 100% (34/34 ) of cases, respectively. The intraclass correlation coefficients for these vessels were 0.89, 0.79, and 0.93, respectively. Conclusions. Th e intraobserver repeatability was acceptable for all the vessels studi ed. (C) 1997 John Wiley & Sons, Inc.