Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is probable background COPD . Heart size at the upper limits of normal or slightly enlarged . Aorta is mildly unfolded and calcified . Increased interstitial markings are seen diffusely in both lungs , but with a relatively patchy distribution . This is similar to radiographs from ___ can ___ and is compatible with previously described chronic interstitial lung changes . No focal consolidation or gross effusion is identified . Allowing for the background interstitial changes , no definite CHF . Metallic density in the upper abdomen most likely represents a vascular stent .
    OUTPUT:
    
Probable background COPD , with chronic interstitial changes in the lungs . In the appropriate clinical setting , it would be difficult to exclude a pneumonic infiltrate or atypical distribution of CHF , but given similarity to prior films , appearances on today 's chest x-ray are likely accounted for by chronic changes . Doubt acute superimposed pulmonary process .