Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac , mediastinal and hilar contours appear unchanged . There is an unchanged persistent diffuse interstitial abnormality . Although vascular congestion may mimic this appearance , the lack of change suggests that this is probably primarily due and perhaps solely due to emphysema and mild interstitial lung disease of long chronicity . There is no pleural effusion or pneumothorax . There has been no definite change .
    OUTPUT:
    
Similar persistent interstitial abnormality .