Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is normal in size . The mediastinal and hilar contours appear within normal limits . There is a persistent patchy left basilar opacity . Given the lack of change , the appearance may be chronic . More generally , there is mild interstitial prominence , perhaps due to slight fluid overload or congestion , but not specific ; other possibilities include atypical infection , airway inflammation , or possibly interstitial lung disease .
    OUTPUT:
    
Mild suspected background interstitial abnormality and unchanged focal left infrahilar opacity , accordingly suggestive of longer chronicity . Clinical correlation is recommended . If shortness of breath were to continue and the possibility of an underlying interstitial process is of potential clinical concern , dedicated chest CT could be considered .