Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is mildly enlarged but not significantly changed since earlier examinations . The cardiac , mediastinal , and hilar contours appear similar . The lungs are clear . There are no pleural effusions or pneumothorax . Mild - to - moderate degenerative changes are similar along the thoracic spine .
    OUTPUT:
    
No evidence of acute disease .