Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiomediastinal and hilar contours are within normal limits . Bibasilar opacities likely relate to atelectasis , however an underlying infectious process can not be entirely excluded . No large pleural effusion or pneumothorax is identified .
    OUTPUT:
    
Biabasilar opacities likely represent atelectasis however an underlying infectious process can not be entirely excluded .