Multimodal Imaging Evaluation of Pulmonary Consolidation in Children: Diagnostic Value of Lung Ultrasound Based on CT Air Bronchogram Grading and Its Correlation With Inflammatory Biomarkers and Clinical Prognosis

ABSTRACT Background The effect of intralesional gas on diagnostic disagreement between chest radiography (CXR) and lung ultrasound (LUS) in pediatric pneumonia is uncertain. In the present study, computed tomography (CT) was used as the reference standard. Bronchial aeration signs within consolidation were graded. The influence of these signs on diagnostic sensitivity and on associations with inflammatory markers was assessed. Methods A retrospective study was performed in 110 children with confirmed pneumonia. Patients were assigned to three grades according to CT morphology of bronchial air signs: Grade 1 (solid/punctate; n = 35), Grade 2 (segmental/discontinuous; n = 35), and Grade 3 (arborized; n = 40). Diagnostic sensitivity was calculated for CXR and LUS. Inflammatory markers (lactate dehydrogenase (LDH), C‐reactive protein (CRP), white blood cell (WBC) count), and clinical outcomes (bronchoscopy rate, length of hospital stay) were compared across grades. Results As lung air content increased from Grade 1 to Grade 3, chest X‐ray sensitivity significantly decreased from 94.3% to 82.5% ( p < 0.01), whereas LUS sensitivity remained stable (> 92%) across all grades ( p > 0.05). Concurrently, Grade 1 consolidation was most conspicuous on CXR. It was also associated with the highest inflammatory markers (LDH 380 ± 80 U/L; CRP 65.4 ± 18.5 mg/L; WBC 14.5 ± 3.5 × 10 9 /L). The bronchoscopy rate was highest in Grade 1 (82.9%) and lowest in Grade 3 (12.5%, p < 0.001). Conclusion Bronchial air trapping was identified as a major confounder for CXR but not for LUS . High diagnostic performance was maintained by LUS for consolidation with abundant bronchial air trapping (Grade 3). Consolidation with minimal bronchial air trapping (Grade 1) was associated with severe airway obstruction and a high requirement for early bronchoscopic intervention.