Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The endotracheal tube terminates in the distal trachea . An enteric tube is also unchanged in position . Since the study of 1 day prior , there is increased retrocardiac opacification which is most likely due to atelectasis . The heart and mediastinum are magnified by the projection . There is no pneumothorax .
    OUTPUT:
    
New left lung base subsegmental atelectasis . Otherwise no significant interval change .