Swyer-James Syndrome is also called "unilateral hyperlucent lung". This a radiologic *classic* where one lung field is more radiolucent (darker) on chest films.

Etiology: likely secondary to childhood adenoviral infection with subsequent acute obliterative bronchiolitis, bronchiectasis, and distal air-space destruction

Clinical Presentation: varies from asymptomatic to DOE, usually relates a history of recurrent childhood respiratory infections

Radiographic Findings
- increased lucency in affected lung (usually entire lung with lobar/subsegmental distribution having been reported)
- small ipsilateral hemithorax with normal-to-decreased volume
- small ipsilateral hilum
- air trapping on expiratory films
- V/Q scan classically shows decreased perfusion as well as diminished ventilation with delayed washout
- angio will show a “pruned tree” appearance of affected side’s pulmonary vasculature