Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiomediastinal and hilar contours are stable from the prior examination . Postoperative changes involving the left hemi thorax and left upper lobe collapse are again noted , There is no pneumothorax or pleural effusion . An endobronchial valve projects over the left hilus as before . Aeration of the left lung is much improved . The right lung is hyperinflated , as before .
    OUTPUT:
    
Stable postop changes in the left lung . Endobronchial valve projects over the left hilus . Improved aeration of the left lung