title: Tilted air-fluid interfaces on chest radiographs.
abstract: Three patients had hydropneumothoraces in which the air-fluid interfaces were tilted from the horizontal. One was examined fluoroscopically, and the interface "seesawed" synchronously with the heartbeat. Displacement of the fluid by cardiac pulsation is the most likely usual cause of tilted air-fluid interfaces in the chest.
mesh_terms: D000388:Air; D006801:Humans; D006872:Hydropneumothorax / Q000000981:diagnostic imaging*; D009200:Myocardial Contraction; D010996:Pleural Effusion / Q000000981:diagnostic imaging*; D011859:Radiography