Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart size is moderately enlarged but unchanged . Mediastinal and hilar contours are stable . The pulmonary vasculature is not engorged . Minimal patchy opacity in the left lung base may reflect atelectasis though infection is not completely excluded . No pleural effusion or pneumothorax is visualized . There are no acute osseous abnormalities .
    OUTPUT:
    
Minimal patchy left basilar opacity could reflect atelectasis but infection is not completely excluded .