Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is an increase in interstitial markings in a predominantly peripheral and basilar distribution consistent with known chronic interstitial lung disease which was previously presumed to reflect nonspecific interstitial pneumonia . Increased opacities at the lung bases likely reflect this progressive fibrosis . The cardiomediastinal silhouette and hilar contours are stable without cardiomegaly . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
Progression of chronic interstitial lung disease . Worsening opacities at the lung bases likely reflect progression of disease however underlying infection is difficult to exclude .