Optimizing Imaging of Pediatric Liver Lesions: Guidelines from the Pediatric LI-RADS Working Group.

A differential diagnosis based on a patient's age, clinical presentation, and serum α-fetoprotein level will help guide the initial imaging workup in children with a liver lesion. Children vary significantly in size, the ability to stay still, and the ability to breath hold for imaging examinations. Choosing and tailoring imaging techniques and protocols for each indication and age group is important for optimal care with minimal invasiveness. The need for sedation or anesthesia can be obviated by using techniques like feed and bundle, distraction, contrast-enhanced US, and motion-insensitive sequences for MRI. US is often the first imaging modality used in children with a suspected abdominal mass. Once a hepatic lesion is confirmed, multiphasic contrast-enhanced MRI is recommended for most lesions as the next imaging modality allowing full characterization of the lesion and assessment of the liver parenchyma. Contrast-enhanced CT can also be performed for assessment of pediatric focal liver lesions, especially in patients who have a contraindication to MRI. Contrast-enhanced US has shown promise to decrease the need for MRI or CT in some lesions such as hemangioma and focal nodular hyperplasia. Children with a history of malignancy can develop multiple types of hepatic lesions at various stages, including infections during an immunocompromised state, manifesting as focal liver lesions. Based on available limited data in the literature and the collective experiences of the Liver Imaging and Reporting Data System Pediatric Working Group, the authors provide guidelines for the imaging workup of pediatric focal liver lesions with an indication- and age-based approach and discuss the selection and performance of various imaging techniques and modalities. ©RSNA, 2022 See the invited commentary by Chojniak and Boaventura in this issue.