Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart size is normal . Minimal tortuosity of the thoracic aorta is noted . The mediastinal and hilar contours otherwise are within normal limits . The pulmonary vascularity is normal . Minimal patchy opacity is demonstrated within the lower lobes on the lateral view , but difficult to localize on the frontal view , possibly within the left lower lobe . No pleural effusion or pneumothorax is present . No acute osseous abnormalities are seen .
    OUTPUT:
    
Patchy opacity within the lower lobe , possibly the left lower lobe , which could reflect atelectasis but infection is not excluded .