Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiomediastinal contours are midline . Postoperative changes in the right hilum are noted . There has been interval improvement in aeration / opacities in the right perihilar region suggesting better aeration of the remaining right middle lobe . The left lung is clear . Patient has known emphysema . There is no pneumothorax or left pleural effusion . Right pleural effusion is a small . Elevation of the right hemidiaphragm is stable . Right chest wall subcutaneous gas collection has almost completely resolved .
    OUTPUT:
    
Improved aeration of the right middle lobe . Small right effusion