Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal radiograph of the chest when compared to the prior study demonstrates mild improvement in opacification at the left middle and lower lung zones . There is continued left lower lobe collapse . Right basilar atelectasis is unchanged . Cardiac and mediastinal contours are stable .
    OUTPUT:
    
Mild improvement in opacity at the left base with otherwise minimal change .