Ultrasound shear wave elastography (SWE) measures liver stiffness non-invasively in chronic liver diseases. Reference values in healthy children by age are needed in clinical practice.

Our study aimed to measure the reference values for liver elasticity by 2D SWE in a pediatric population stratified by age.

This retrospective study included 266 children without liver disease referred for an abdominal or renal ultrasonography from February 2022 to April 2022. Shear wave elasticity and shear wave speed were measured with a convex (6C1) or linear (SL15–4) transducer with a Canon Aplio 500 Aplio system performed for another reason in healthy children aged 0 to 19 years distributed in five age groups.

Median liver elasticity value was 5.50 kPa (interquartile range [IQR] 4.9–6.3) overall. Global analyses revealed values decreasing with increasing age from newborn to adolescence (elasticity: 6.0 kPa [IQR 5.4–6.5] to 5.3 kPa [IQR 4.7–6.4]; speed: 1.41 m/s [IQR 1.34–1.47] to 1.33 m/s [IQR 1.27–1.46], p < 10^–3). Elasticity values were lower with the convex than linear transducer (5.20 kPa [IQR 4.7–5.8] vs 6.2 kPa [IQR 5.6–6.6], p < 10^–4). Elasticity values increase with increasing age if we study each probe individually (from 1 year old to older). Median elasticity values were not associated with sex after adjustment for age or with BMI.

Our study provides reference values for liver elasticity in healthy children by age and for two probes using an Aplio system. Liver elasticity values differed according to the probe used.