Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are slightly hyperinflated . Mild bullous emphysema is seen within the lower lobes . There is no pneumothorax , focal consolidation , or pleural effusion . The heart size is normal . The hilar and mediastinal contours are within normal limits .
    OUTPUT:
    
Mild emphysema . No acute intrathoracic process .