Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Subtle bibasilar opacities may be due to atelectasis however aspiration or early infection or not excluded . No pleural effusion or pneumothorax is seen . The cardiac and mediastinal silhouettes are unremarkable .
    OUTPUT:
    
Subtle bibasilar opacities may be due to atelectasis but subtle aspiration or early infection not excluded .