Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac , mediastinal and hilar contours appear stable . There is no pleural effusion or pneumothorax . Post-operative changes in the mediastinum and left chest wall are stable . The chest is hyperinflated . There is possibly a trace pleural effusion on the left side only . The lungs appear clear .
    OUTPUT:
    
No evidence of acute disease .