Development of a semi‐automated tool to measure fetal abdominal wall thickness during ultrasound at 20 weeks' gestation

Abstract

ObjectivesTo develop a semi‐automated tool for measuring fetal abdominal wall thickness (AWT). To validate the software using images captured by other centers and create a nomogram for fetal AWT between 18 and 20 weeks.MethodsA semiautomated tool that measured AWT was developed using images captured at the routine 20‐week morphology scan. The software was developed using digital images captured routinely during scans of low‐risk women. Inter‐ and intraobserver reliability was assessed between manual and semi‐automated measures. The tool was validated using images acquired from other centers. Linear regression and quadratic polynomials were used to create a nomogram for AWT.ResultsThe semi‐automated tool was able to measure AWT in all images. Interoperator reliability was 0.90 and 0.97 (P < 0.05) for manual and semi‐automated methods, respectively. Measurement agreement varied between three operators from moderate to excellent (0.77, 0.87, 0.92), with overall agreement being good (0.85). The tool could be successfully applied to 89% of images from other centers. A nomogram was generated for AWT measurements of fetuses at 18–20 weeks in normal, low risk mothers.ConclusionSemi‐automated measurement of AWT was feasible using images captured during the routine 20‐week scan. This approach had lower inter‐ and intraobserver variability compared to manual measurement.