Diagnostic Accuracy of Bedside Lung Ultrasound Versus Chest X-ray for Pediatric Pneumonia in Children Under Five: A Comparative Study

Background: Pneumonia remains a major cause of under-five mortality, particularly in low-resource settings where early diagnosis is crucial. While chest X-ray (CXR) is the conventional imaging modality, it is limited by radiation exposure and accessibility. Bedside lung ultrasound (LUS) has emerged as a promising, radiation-free alternative, offering real-time pulmonary assessment. Objectives: To evaluate the diagnostic accuracy of bedside LUS compared to CXR in children under five presenting with clinical signs of pneumonia, and to analyze the sonographic features associated with pneumonia. Methods: A prospective observational study was conducted on 161 children aged one month to five years with clinical suspicion of pneumonia at a tertiary care hospital over 18 months. LUS was performed at the bedside using a standardized 10-zone protocol. Chest radiographs were interpreted by radiologists blinded to LUS findings. Statistical analysis included sensitivity, specificity, predictive values, and logistic regression for significant predictors. Results: LUS showed significantly higher sensitivity (86.2%, n=139/161, p=0.0001) and specificity (94.4%, n=85/90, p=0.0001) than CXR (75.6%, n=122/161, and 85.4%, n=77/90, respectively). Key sonographic markers such as shred sign and air bronchograms demonstrated strong diagnostic value. Subpleural consolidations and pleural effusions were better detected with LUS. Shred sign (odds ratio (OR)=8.45) and CRP >20 mg/L (OR=3.50) emerged as strong independent predictors of pneumonia. Conclusion: Bedside LUS is a reliable and accurate diagnostic modality for pediatric pneumonia. It is especially valuable in early detection and in resource-limited settings, supporting its broader clinical integration.