Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Median sternotomy wires are unchanged in position . Bibasilar opacities are again noted , slightly improved on the left side when compared ___ . There are small pleural effusions bilaterally . No evidence of pneumothorax . The heart size is within the upper limits of normal . The mediastinum appears normal .
    OUTPUT:
    
Bibasilar opacities , slightly improved on the left . This likely represents atelectasis .