Purpose or Case Report: To review the CT features of childhood interstitial lung diseases (ChILD).
Methods & Materials: We illustrate specific examples of ChILD from our patient cohort at a large national childrens hospital alongside their histopathology, in order to demonstrate CT features of interstitial lung disease within the paediatric population.
Results: Although rare, interstitial lung disease in the paediatric population is very different from that seen in adulthood and infers significant morbidity and mortality.

Imaging plays a crucial role in the assessment of these patients, sometimes demonstrating features consistent with individual pathological diagnoses, demonstrating the distribution and extent of disease and guiding any subsequent biopsy.

We review techniques in paediatric thoracic CT and illustrate the specific disorders below.

Childhood interstitial lung diseases (ChILD) can be divided into 2 groups:

1) Conditions more prevalent in infancy - diffuse developmental disorders (we present images of congenital alveolar dysplasia), lung growth abnormalities (cystic lung disease in trisomy 21 and filamin A protein deficiency related lung disease), conditions of unknown aetiology (neuroendocrine hyperplasia of infancy - NEHI) and surfactant dysfunction mutations (pulmonary alveolar proteinosis in ABCA3 dysfunction).

2) Conditions not specific to infancy – Normal host (constrictive obliterative bronchiolitis), immunocompromised host (Lymphocytic interstitial pneumonitis – LIP and pleuroparenchymal fibroelastosis - PPFE), disorders relating to systemic processes (Gaucher disease, Niemann-Pick and Langerhan’s cell histiocytosis) and masqueraders of ChILD (pulmonary lymphangiectasia and pulmonary veno-occlusive disease).
Conclusions: Childhood interstitial lung disease comprises a rare and diverse group of conditions. Imaging and histological correlation is crucial in the investigation and management of these patients and offers fascinating insights into these unusual conditions.