Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is no focal consolidation , effusion , or pneumothorax . Hyperexpanded lungs and attenuation of pulmonary vessels in the upper lobes are compatible with mild centrilobular emphysema as seen on the prior CT chest . The cardiomediastinal silhouette is normal . No free air below the diaphragms seen .
    OUTPUT:
    
No acute intrathoracic process . Mild emphysema .