Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size is normal . Mediastinal and hilar contours are unremarkable . The pulmonary vasculature is normal . The lungs are hyperinflated with emphysematous changes re - demonstrated . Patchy opacity is noted in the left lung base . Remainder of the lungs are clear . No focal consolidation , pleural effusion or pneumothorax is seen . There are mild degenerative changes in the thoracic spine . Remote bilateral rib fractures are noted .
    OUTPUT:
    
Patchy left basilar opacity may reflect atelectasis , but pneumonia is not excluded in the correct clinical context . Emphysema .