Technical Notes on Liver Elastography: A Guide for Use in Neonates in Intensive Care Units

Background/Objectives: Liver elastography is increasingly used in neonatal intensive care units (NICUs) as a non-invasive, radiation-free, reproducible technique for assessing liver stiffness. This technique demonstrates substantial advantages over conventional ultrasound in diagnosing diffuse liver diseases by providing quantitative measures of tissue elasticity. This article aims to describe the most critical milestones for performing liver elastography ultrasound point-of-care, a tool increasingly used to complement traditional ultrasound in the study of the liver in intensive care units where the population is very susceptible to manipulation. Methods: Techniques such as point-shear wave elastography (pSWE) and two-dimensional shear wave elastography (2D-SWE) have become key in evaluating conditions such as hypoxic-ischemic liver disease, cholestatic diseases, storage and metabolic disorders, or infectious liver conditions. However, despite its usefulness, performing elastography in neonates, particularly in those weighing less than 1000 g or in high-frequency oscillatory ventilation, presents notable challenges, including the extreme sensitivity of neonates to touch, noise, and temperature changes and the difficulty in obtaining accurate measurements due to limited hepatic depth. Results: Key factors for the success of sonoelastography in this population include minimizing contact time, adjusting mechanical and thermal indices to meet biosecurity guidelines, and ensuring patient comfort and stability during the procedure. Despite these challenges, elastography has proven helpful in routine clinical practice. Conclusions: The growing evidence on elastography has provided standardized reference values, further enhancing its clinical applicability in NICU settings.