Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Chronic fibrotic changes at the lung bases are compatible with known interstitial lung disease . There is no focal consolidation to suggest pneumonia ; however , the lung bases are obscured by the chronic changes . Heart size and mediastinal contours are normal . No pleural effusion or pneumothorax .
    OUTPUT:
    
Interstitial lung disease related chronic fibrotic changes at the lung bases , with no strong evidence for acute pneumonia .