Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral views of the chest . Heart size and mediastinal contours are stable . Interstitial edema has slightly improved since the prior exam . There is mild persistent bibasilar atelectasis . No pneumothorax or pleural effusion .
    OUTPUT:
    
Interval improvement of interstitial edema . Mild persistent bibasilar atelectasis .