Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Stable cardiomediastinal appearance . Dense retrocardiac opacification likely represents a combination of a stable moderate left pleural effusion and atelectasis . Trace right pleural effusion noted . Linear density within the right middle lung consistent with atelectasis . No pneumothorax evident . Sternotomy sutures are midline and intact .
    OUTPUT:
    
Dense retrocardiac opacification , likely combination of a moderate left pleural effusion and atelectasis . Stable small right pleural effusion .