Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest ___ at 831 are submitted .
    OUTPUT:
    
There is a developing airspace opacity in the right upper lung which would be concerning for aspiration or pneumonia . In addition , linear opacity in the right mid lung and at the left base likely reflect subsegmental atelectasis or scarring . A small layering right effusion is likely unchanged . The retrotracheal mediastinal structure indenting the posterior tracheal wall on the lateral view is stable possibly related to recent surgery . Clinical correlation is advised . No evidence of pulmonary edema . Overall cardiac and mediastinal contours are stable . No pneumothorax .