Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiomediastinal and hilar contours are stable . The right lung is clear . Obscuration of the left hemidiaphragm may be related to atelectasis at the left base however infection should be considered . There may be a small effusion at the left base . No pneumothorax .
    OUTPUT:
    
Left basal opacity may reflect atelectasis or infection .