OBJECTIVE: The objectives of this study are: (1) to standardize the sonographic biometry method to determine the size of the liver in children in order to obtain a greater precision of the section planes and to minimize operator-dependant error; (2) to test intra-observer reproducibility. CASUISTIC AND METHOD: Sonographic measurements of the liver were performed by a single examiner in 32 children (aged 0 to 6 years) with no liver or biliary system disease. The measurements were done in two different occasions (exams 1 and 2) to determine reproducibility. The section planes were based on external orientation lines related to intra-abdominal anatomic references, both extra and intra-hepatic. The values obtained in exams 1 and 2 were compared using a Student's paired t-test. The Pearson's coefficient was employed to determine the correlation among parameters as well as the correlation between the children's age and the difference in the values of exams 1 and 2. RESULTS: The statistical analysis revealed no significant intra-observer variability and no significant correlation between measurements' difference and children's age. In general, parameters were directly and highly correlated (r > 0.60). CONCLUSION: We concluded that the method is reproducible when performed by a same examiner. The measurements of the cranio-caudal diameter at the midsternal line and the posterior cranio-caudal diameter at the midclavicular line, based on intra-hepatic anatomic references, were precise and easier to perform than other routine measurements.

Keywords: Liver size, Biometry, Children, Ultrasound