Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiomediastinal contours are unchanged . Known left perihilar mass is better seen in prior CT . There is no pneumothorax . There is a small right effusion . There are mild degenerative changes in the thoracic spine
    OUTPUT:
    
There is a small right effusion . There are no new lung abnormalities . Known left hilar mass better seen in prior CT .