Reproducibility of fetal brain measurements using 3D ultrasound
Obstetrics and Gynaecology (East Africa)
Objectives: To establish the inter- and intra-operator reproducibility of key fetal brain structures throughout gestation using 3D ultrasound.
Methods: 3D volumes of the fetal head between 15 and 40 weeks of gestation were acquired prospectively using a standardized protocol as part of the INTERGROWTH-21st Project. For this reproducibility study a random sample of 90 volumes was used. The following measurements were taken: width of the posterior lateral ventricle in the transventricular plane; depth of the parieto-occipital fissure and Sylvian fissure in the transthalamic plane; and width of the cisterna magna and transcerebellar diameter in the transcerebellar plane. Operators worked in pairs. The first extracted the three planes of interest and took all measurements twice; this was repeated by the second operator. The effect of caliper replacement was also assessed. Mean differences and limits of agreement (LOA) were calculated using Bland-Altman plots.
Results: As there was a significant change with gestation in the transcerebellar diameter measurements, differences were expressed in percentage terms; the mean difference (95% LOA) was <1% (±12%). All other structures were compared in mm, and their mean differences (95% LOA) were ≤ 0.2mm (±2.8mm) (table 1). The greatest proportion of variability was due to caliper replacement.
Conclusions: Measurement of brain structures using standardized 3D fetal head volumes is highly reproducible. Caliper placement accounts for most of the observed variation among operators.
Ultrasound in Obstetrics and Gynecology
Papageorghiou, A. T.
(2014). Reproducibility of fetal brain measurements using 3D ultrasound. Ultrasound in Obstetrics and Gynecology, 44(S1), 100.
Available at: http://ecommons.aku.edu/eastafrica_fhs_mc_obstet_gynaecol/130