Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size remains mildly enlarged . Mediastinal and hilar contours are unremarkable . Pulmonary vasculature is normal . Patchy opacities are noted in both lung bases , findings which could reflect atelectasis as the lung volumes are somewhat low , but infection can not be completely excluded . No pleural effusion or pneumothorax is present . There are no acute osseous abnormalities .
    OUTPUT:
    
Low lung volumes with patchy bibasilar opacities , likely atelectasis . Infection however can not be completely excluded in the correct clinical setting .