Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size is mildly enlarged . The mediastinal and hilar contours are unremarkable . Pulmonary vasculature is not engorged . Patchy opacities in the lung bases may reflect atelectasis , but infection is not excluded in the correct clinical setting . No pleural effusion or pneumothorax is detected . Mild degenerative changes are noted in the thoracic spine .
    OUTPUT:
    
Mild bibasilar opacities may reflect atelectasis . Infection is not excluded in the correct clinical setting .