Normal mediastinal and hilar lymph nodes in children on multi-detector row chest computed tomography

OBJECTIVE: To study normal mediastinal and hilar lymph nodes on multi-detector chest computed tomography (CT). METHODS: A cohort of 120 children aged 1–17 years underwent emergency CT, including the chest, after high-energy trauma. Axial 5-mm reconstructions were evaluated for lymph nodes at hilar and various mediastinal levels and the short-axis diameters were measured. RESULTS: At least one lymph node was found in 115 (96%) children, with subcarinal (69%), lower paratracheal (64%) and hilar (60%) nodes being most common. Up to 10 years of age most lymph nodes were smaller than or equal to 7 mm. In older children lymph nodes measuring up to 10-mm-short-axis diameter were found. Lymph nodes were rare along the mammary vessels, at lower oesophageal and at prevascular and posterior mediastinal levels in children. CONCLUSION: Mediastinal and hilar lymph nodes are more common than previously thought, probably because of increased detection by modern multi-detector CT. Lymph node location and age have to be taken into account when evaluating lymph nodes in the paediatric chest. Key Points • The size and location of normal lymph nodes is of great diagnostic importance • There is little relevant published information related to pediatric chest computed tomography • We provide normative data concerning mediastinal and hilar lymph nodes in children • These normal values can help identify abnormal lymph nodes in children