Establishing CT-derived Normative Liver and Spleen Volumes for Children: Validation in Regional and International Datasets.

Background Volumetric evaluation of liver and spleen size is useful, yet pediatric reference values remain limited and lack external validation. Purpose To establish normative liver and spleen volumes from contrast-enhanced CT in children and validate them in external regional and international datasets. Materials and Methods In this retrospective study, contrast-enhanced abdominal CT scans (patient age, 2-18 years) from Asan Medical Center and Pusan National University Yangsan Hospital (January 2005 to June 2021) were collected for the derivation dataset. Patients with chronic diseases, liver and/or spleen imaging abnormalities, or missing height and/or weight measurement within 3 months were excluded. Portal-phase CT images were segmented automatically with manual correction. Data from Seoul National University Children's Hospital (January 2018 to December 2021) and Cincinnati Children's Hospital Medical Center (January 2018 to July 2021) were used for regional and international validation, respectively. Model performance was assessed with the average pinball loss and absolute errors for predicting 50th percentiles. Results A total of 1298 children (median age, 11.3 years [IQR, 8.0-15.0 years]; 660 female) were included (derivation set, n = 1030 [all Asian]; regional validation set, n = 114 [all Asian]; international validation set, n = 154 [racially diverse]). The model including sex, height, and weight had the lowest average pinball loss for predicting 50th percentile liver (54.50 mL) and spleen (18.64 mL) volume and was therefore selected. Compared with previously published formulas, the model showed lower average pinball loss in the regional validation dataset for both liver (5th, 11.55 mL vs 11.93 mL; 50th, 50.88 mL vs 55.47-116.02 mL; 95th, 15.85 mL vs 19.49 mL) and spleen volumes (5th, 3.69 mL vs 3.74 mL; 50th, 15.19 mL vs 16.03 mL; 95th, 5.01 mL vs 5.59 mL). In international external validation, the average pinball loss was lower for the 50th percentiles (liver, 50.28 mL vs 50.30 mL; spleen, 20.97 mL vs 21.42 mL), and absolute errors were comparable (liver, 100.56 mL vs 100.60 mL [P = .53]; spleen, 41.93 mL vs 42.83 mL [P = .69]). Conclusion Normative liver and spleen volumes in children derived using quantile regression models and the respective predictive performance were presented. © RSNA, 2026 Supplemental material is available for this article.