Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart size is normal . The hilar and mediastinal contours are normal . Mild linear scarring is again seen in the right lower lobe , overall unchanged compared to the prior exam . No focal consolidations concerning for pneumonia are identified . Old left rib fractures are stable . There is no pneumothorax or pleural effusion .
    OUTPUT:
    
No acute intrathoracic abnormalities identified . Changes are consistent with emphysema .