Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral chest radiographs demonstrate pain heart which is top - normal in size , unchanged . Opacity in the left infrahilar region is without definite correlate on lateral view . This appears slightly improved compared to ___ . A retrocardiac opacity likely represents a left lower lobe bronchus en face . There is no appreciable pleural effusion or pneumothorax .
    OUTPUT:
    
Improving left lower lobe opacity compared to ___ .