[Cryptogenic organizing pneumonia: typical and atypical imaging features on computed tomography].

Organizing pneumonia (OP) occurs without any identifiable cause ("cryptogenic organizing pneumonia") as well as secondary to a multitude of disorders of various origins ("secondary organizing pneumonia"). Possible triggers are infections, drugs, collagen vascular disease, inflammatory bowel disease, transplantations, and radiation directed to the chest. The present manuscript provides an overview of the histopathological, clinical and CT imaging features of OP. Classic CT morphologies (peripheral and peribronchovascular consolidations and ground glass opacities) and atypical imaging features (nodules, crazy paving, lines and bands, perilobular consolidations and the reversed halo sign) are discussed.