Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is normal in size . The mediastinal and hilar contours appear unchanged . Streaky left basilar opacity suggests minor unchanged atelectasis or scarring . Otherwise , the lungs appear clear . There is no pleural effusion or pneumothorax . Mild degenerative changes are similar along the thoracic spine .
    OUTPUT:
    
No evidence of acute disease .