Small airway diseases.

High-resolution CT scan is currently the best imaging technique for assessment of diseases of the bronchioles. This article describes the anatomic basis for the findings. This is followed by a presentation of the findings in bronchiolitis, as it is currently classified, into five main groups: (1) cellular bronchiolitis, (2) panbronchiolitis, (3) respiratory bronchiolitis, (4) constrictive bronchiolitis, and (5) bronchiolitis obliterans with intraluminal polyps.