Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is at the upper limits of normal size . There is similar mild unfolding of the thoracic aorta . The mediastinal and hilar contours appear stable . The lungs appear clear . There are no pleural effusions or pneumothorax . Bony structures are unremarkable aside from mild degenerative changes along the lower thoracic spine .
    OUTPUT:
    
No evidence of acute disease .