Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is normal in size . The cardiac , mediastinal , and hilar contours appear within normal limits . There is no pleural effusion or pneumothorax . Irregular central lower opacities in each lung appear somewhat less prominent than on the prior study and small round lucencies are less visible . There is suspicion that this may be due to a process of chronic scarring from prior infection although it is difficult to exclude coinciding active atypical pneumonia or mild pulmonary edema as possible etiologies .
    OUTPUT:
    
Central opacities in both lungs , similar to decreased although apparent change to some extent may be due to differences in technique . This appearance is probably compatible with chronic scarring from prior infection although superimposed atypical pneumonia or even pulmonary edema are not excluded by this study . Short - term follow - up radiographs may be helpful .