Bronchiolitis: classification, computed tomographic and histopathologic features, and radiologic approach.

The introduction of thin-section computed tomography (CT) has improved the diagnosis of bronchiolitis and contributed to establish bronchiolitis as an important part of pulmonary medicine. The histopathologic groups of bronchiolitis include cellular bronchiolitis, diffuse panbronchiolitis, follicular bronchiolitis, respiratory bronchiolitis, proliferative bronchiolitis, constrictive bronchiolitis, and mineral dust airway disease. Bronchiolitis can be readily identified and may lead to characteristic findings on thin-section CT. Various bronchiolitis manifests as one or a combination of 3 main patterns in thin-section CT: centrilobular nodules and branching densities, ground-glass attenuation and consolidation, and low attenuation and mosaic perfusion pattern.