Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are normally expanded . Faint , ill - defined opacities at the lung bases are improved since ___ . The heart is top normal . The mediastinal and hilar contours are normal . There is no pleural effusion or pneumothorax . There is no confluent consolidation to suggest pneumonia .
    OUTPUT:
    
Faint opacities at the lung bases are improved since ___ , possibly chronic atelectasis . There is no convincing evidence of pneumonia .