Which of the following imaging patterns would most strongly indicate bronchiolitis rather than pneumonia?

• A. Pleural effusion
• B. Hyperinflation with peribronchial thickening and no focal consolidation
• C. Large mediastinal mass
• D. Focal lobar consolidation

Answer: (D)

Bronchiolitis in infants typically causes inflammation and mucus plugging of the small airways, leading to air trapping. On imaging this shows up as hyperinflation with peribronchial thickening and, importantly, no discrete focal consolidation in a single lobe. Pneumonia, in contrast, often presents with alveolar filling in a lobe, producing focal lobar consolidation. So the pattern of hyperinflation with peribronchial thickening and no focal consolidation best indicates bronchiolitis. Pleural effusion can accompany pneumonia but isn’t specific, a large mediastinal mass isn’t characteristic of bronchiolitis, and focal lobar consolidation would point toward pneumonia rather than bronchiolitis.