Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is at the upper limits of normal size . The mediastinal and hilar contours appear unchanged . There is a mild background interstitial abnormality , but no evidence for acute change or focal consolidation . The lungs are hyperinflated . There are no pleural effusions or pneumothorax . Mild degenerative changes are present along each acromioclavicular joint . Mild osteophyte formation is noted along the lower thoracic spine with slight anterior wedging that appears unchanged among several lower thoracic vertebral bodies .
    OUTPUT:
    
No evidence of acute disease .