Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP portable upright view of the chest . Increased opacity at the left lung base is concerning for atelectasis and effusion . The right lung appears grossly clear . Heart size is within normal limits . Mediastinal contour is unremarkable . No free air seen below the right hemidiaphragm .
    OUTPUT:
    
Left basal opacity concerning for effusion and atelectasis . Please refer to subsequent CT chest for further details .