Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The endotracheal tube and enteric tube remain in standard positions . There is persistent opacification of the left hemithorax with leftward shift of the mediastinal structures . There is minimal improved aeration within the left lung base , but continued marked atelectasis of the left lung with at least a small left pleural effusion . Fiducial marker indicating the site of an endobronchial lesion in the left mainstem bronchus is re - demonstrated . Right lung remains clear . No pneumothorax is identified .
    OUTPUT:
    
Slight interval improvement in aeration of the left lung base , but overall there is continued marked left lung atelectasis with at least a small left pleural effusion and persistent leftward shift of the mediastinal structures .