Bronchiolitis Obliterans Etiology: bronchiolar inflammation with submucosal peribronchial fibrosis, often seen post-viralCXR: bronchial dilation, hyperinflation, reticulonodular infiltrates Cases of Bronchiolitis Obliterans CXR (above) shows chronic interstitial infiltrates in both lungs. Bronchograms of both lungs (below) shows airway dilation, left greater than right.