Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiomediastinal and hilar contours are within normal limits . A very subtle reticular opacity at the base of the left lung may reflect subsegmental atelectasis or infection . No pneumothorax or pleural effusion .
    OUTPUT:
    
Very subtle reticular opacity at the base of the left lung may represent subsegmental atelectasis or infection / aspiration .