Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low . Opacity in the left retrocardiac region may be atelectasis or aspiration . There is no pleural effusion or pneumothorax . The cardiomediastinal silhouette is unchanged . The patient remains rotated to the left .
    OUTPUT:
    
Low lung volumes , with retrocardiac opacity which may represent atlectasis or aspiration .