Accuracy and reproducibility of ultrasound measurements in obstetric management

OBJECTIVE: The aim of this study was to assess the potential of ultrasonography as a routine diagnostic tool in obstetric management. SUBJECTS AND METHODS: For the investigation on interobserver reproducibility, 2 sonologists independently measured the biparietal diameter (BPD), femur length (FL), amniotic fluid index (AFI), and resistance index (RI) of the umbilical and middle cerebral arteries in 20 healthy pregnant women between 28 and 36 weeks of gestation using color and pulsed Doppler ultrasound. A second group of 10 healthy pregnant women between 30 and 35 weeks of gestation were examined to assess the level of intraobserver reproducibility of the Doppler and ultrasound measurements by 2 sonologists. For each patient in this group, the flow waveform was measured three times in succession. Calculations of the intraclass correlation coefficient (Ri) were used to determine the levels of reproducibility. The agreement was considered acceptable only when the Ri value was > or = 6. RESULTS: The interobserver Ris for BPD, FL, AFI, and RI of the umbilical and middle cerebral arteries were 0.93, 0.8, 0.58, 0.49 and 0.56, respectively. The intraobserver Ris of the 2 sonologists in BPD, FL, and RI of umbilical artery were >0.6, whereas those in AFI and RI of middle cerebral artery were <0.6. CONCLUSIONS Both the interobserver and intraobserver reproducibilities of BPD and FL were clinically acceptable, but not in the AFI and RI of umbilical and middle cerebral arteries.