Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Left basilar opacity may reflect atelectasis , and the lungs are otherwise clear without focal consolidation , pleural effusion or pneumothorax . There is no overt pulmonary edema . The heart is normal in size . The mediastinal contours are normal . Presumed right lower cervical hardware is visualized .
    OUTPUT:
    
Left basilar retrocardiac opacity which could be due to atelectasis although pneumonia is possible in the proper clinical setting .