Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are hyperinflated and the diaphragms are flattened , consistent with COPD . The cardiomediastinal silhouette is unchanged . There is upper zone redistribution , without overt CHF . Mild prominence of interstitial markings could reflect underlying chronic changes . No focal infiltrate , focal consolidation , effusion or pneumothorax is detected . Advanced multilevel thoracic spine degenerative changes noted .
    OUTPUT:
    
Probable background COPD . Possible subtle chronic interstitial changes . No definite superimposed infiltrate .