Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Reticular opacities in mid and lower lungs are improved since ___ . Upper lobe predominant emphysema is unchanged . The heart size is normal . Mediastinal contours are normal . No bony abnormality is detected .
    OUTPUT:
    
Reticular opacities in mid and lower lungs may reflect scarring from prior infection but short term follow up CXR may be helpful to exclude pneumocystis or atypical pneumonia .