Tiny Torsos, Tight Consensus: A Prospective Interobserver Study on Abdominal Ultrasound in Preterm Infants

Background Accurate organ measurement is essential in neonatal ultrasound in order to guide clinical decisions. However, interobserver variability remains a challenge, especially in preterm infants, where small organ dimensions and technical limitations can affect reproducibility. Consistent agreement between examiners is crucial to ensure reliable and standardized assessments. This prospective observational study evaluates interobserver agreement in ultrasound measurements of the liver, kidney, and spleen in preterm infants. Methods In this prospective observational study, a total of 74 ultrasound examinations were performed in 30 preterm infants, with seven infants being measured twice. The 37 paired assessments included independent measurements of the liver (midsternal line (MSL), midclavicular line (MCL), and anterior axillary line (AAL)), kidneys, and spleen by two experienced examiners. Statistical analyses included the Wilcoxon matched-pairs signed rank test, paired t -test, Pearson correlation coefficient (PCC), intraclass correlation coefficient (ICC), and Bland–Altman analysis. Results No significant differences were found between examiners ( P > .05), except for the generally least reproducible liver length in the MCL. PCC and ICC values for all measurements exceeded 0.929, indicating excellent interobserver agreement. Conclusion Ultrasound investigations remain a reliable and reproducible tool for organ size assessment in neonatal care, even in extremely low birth weight infants with tiny anatomical structures. The strong interobserver agreement emphasizes the importance of standardized measurement protocols and ultrasound training, ensuring consistency in clinical practice.