Predominant Pattern & or Distribution
Centrilobular, tree in bud nodules
Additional Findings
Micronodular pattern with sparing of the pleural surface; Nodules have a "V" or "Y" shape because of involvement of the small airways as well as the alveoli. Less likely to be infectious because nodules have a very constant size and are diffuse and the larger airways look normal. Tree in bud - maximum intensity projection (MIP) demonstrates tree in bud better than standard lung window series i.e. bronchiolitis or arteriolitis
RB-ILD, hypersensitivity bronchiolitis, infectious bronchiolitis (viral, mycobacteria), follicular bronchiolitis, diffuse pan-bronchiolitis.
DDX
Etiology
Excipient lung disease.