Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac , mediastinal and hilar contours appear stable . A central line has been removed . There is probably a trace pleural effusion on the left . Opacity has decreased in the right cardiophrenic angle and patchy retrocardiac opacity , probably due to atelectasis although not specific , is similar to slightly decreased .
    OUTPUT:
    
Persistent but decreasing opacities at the lung bases . Removal of central line .