Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac , mediastinal and hilar contours are normal . The pulmonary vasculature is normal . Patchy left basilar opacity likely reflects atelectasis , but infection can not be excluded . Right lung is clear . No pleural effusion or pneumothorax is seen . No acute osseous abnormalities identified .
    OUTPUT:
    
Left basilar patchy opacity , likely atelectasis . Infection is not completely excluded .