Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are slightly low . Linear opacity at the left base is unchanged since ___ and may reflect scarring . There is no evidence of pneumonia . The cardiomediastinal silhouette and hilar contours are normal . There is no pleural effusion or pneumothorax . There are surgical drains in the right upper quadrant .
    OUTPUT:
    
Low lung volumes . No evidence of pneumonia .