Comparative Evaluation of Chest Ultrasound and Chest X-ray in Diagnosing Lower Respiratory Tract Infections in Children: A Cross-Sectional Study

Background : Lower respiratory tract infections (LRTIs) are a leading cause of pediatric morbidity. This prospective observational cohort study compares the diagnostic efficacy of chest ultrasound (CUS) and chest X-ray (CXR) in children with suspected LRTIs at Al-Azhar university Hospital (Assuit, Egypt). Methods : A total of 172 children (mean age 5.3 ± 3.2 years) presenting with cough, fever, tachypnea, or chest retractions underwent both CUS and CXR. Ultrasound findings (A-lines, B-lines, consolidation, effusion) and CXR findings (bronchovascular markings, consolidation, effusion) were analyzed. Sensitivity, specificity, interobserver agreement (Cohen’s κ), and diagnostic accuracy (AUC-ROC) were calculated. Results : · CUS demonstrated higher sensitivity for consolidation (90% [95% CI: 85–94%]) and pleural effusion (85% [95% CI: 78–91%]) compared to CXR (78% [95% CI: 71–84%] and 65% [95% CI: 57–72%], respectively). · Specificity for consolidation and effusion was 80% (CUS) vs. 75% (CXR) and 88% (CUS) vs. 80% (CXR). · Interobserver agreement was excellent for CUS (κ = 0.89) and good for CXR (κ = 0.78). · CUS showed superior diagnostic accuracy (AUC = 0.90) versus CXR (AUC = 0.78). · Logistic regression identified CUS findings as stronger predictors of LRTI (OR = 3.5, p < 0.001) than CXR (OR = 1.8, p = 0.02). Conclusion : Chest ultrasound is a sensitive, radiation-free tool for diagnosing pediatric LRTIs, particularly for consolidation and effusion. While CXR remains valuable for bronchovascular markings, CUS should be prioritized in settings where minimizing radiation exposure is critical. A combined approach optimizes diagnostic accuracy.