Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is normal in size . The mediastinal and hilar contours appear stable . There is patchy opacities at the left lung base with very mild elevation of the left hemidiaphragm , suggesting mild atelectasis . Otherwise the lungs appear clear . There is no pleural effusion or pneumothorax . A fracture of the left posterior lateral fourth rib appears unchanged consistent with an older injury . Mild volume loss of a lower thoracic vertebral body is stable . A mid thoracic compression deformity of mild to moderate degree is also unchanged .
    OUTPUT:
    
No evidence of acute injury . Minor left basilar atelectasis .