Background Lung ultrasonography (LUS) is advocated as a tool in diagnosis of paediatric community-acquired pneumonia (CAP). Necrotizing pneumonia, a complication of paediatric CAP, is usually diagnosed by using chest computed tomography (CT). The aim of our study was to evaluate the value of LUS in diagnosis and outcome prediction of paediatric necrotizing pneumonia.

Materials and methods Children, being underwent LUS and diagnosed with CAP, were enrolled. The image findings of enrollers, who receiving chest CT within 5 days, were then analysed for the agreement between LUS and CT. Predictors of clinical outcome were further investigated using the characteristics of LUS.

Results Among children (n = 236) with CAP and undergoing LUS, 96 children also received chest CT within 5 days. High agreement between decreased-to-poor perfusion in LUS and moderate-to massive necrosis in CT was disclosed (k = 0.668). Children, presenting decreased-to-poor perfusion and hypoechoic spaces in LUS, were highly risky for pneumatocele formation (odds ratio 10.11; 95% CI, 2. 95–34.64) and rescue surgical lung resection (odds ratio 8.28; 95% CI, 1. 86–36.93). Longer hospital stay can be predicted if decreased-to-poor perfusion and moderate-to-massive pleural effusion were found in LUS (odds ratio 3.08, 95% CI, 1. 15–8.29).

Conclusion LUS offers substantial concordance with chest CT in diagnosis of paediatric CAP with necrotizing change. Some characteristics of LUS, such as impaired perfusion and hypoechoic spaces, provide good prediction of poor clinical outcome. It should be routinely used in the clinical care of paediatric CAP.