Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac , mediastinal and hilar contours are normal . The pulmonary vascularity is normal . Minimal streaky opacity in the retrocardiac region may reflect atelectasis , though infection can not be completely excluded . No consolidation , pleural effusion or pneumothorax is present . There are no acute osseous abnormalities .
    OUTPUT:
    
Streaky opacity in the left lower lobe which could reflect atelectasis , though infection can not be completely excluded .