Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is normal in size . The mediastinal and hilar contours appear within normal limits . Lung volumes are low . There is questionable retrocardiac opacity . Minor atelectasis is likely but early developing infection is not entirely excluded . There is no pleural effusion or pneumothorax . The bony structures are unremarkable .
    OUTPUT:
    
Streaky opacity in the retrocardiac area , probably atelectasis . Developing pneumonia seems less likely but difficult to exclude and the possibility can be correlated with clinical presentation .