Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is a subtle opacity in the left lung base which may represent a developing consolidation . The right lung is clear . The cardiomediastinal silhouette , hilar contours , and pleural surfaces are normal . There is no pleural effusion or pneumothorax . There is no free air under the diaphragm .
    OUTPUT:
    
Subtle opacity at the left lung base which could represent a developing consolidation in the appropriate clinical setting . No free air under the diaphragm .