Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Small right pleural effusion tracking along the right lateral chest wall has slightly improved since prior study . Atelectasis along the right mid lung has also improved . No left pleural effusion . No pneumothorax is seen . The heart size is top - normal . The hilar and mediastinal contours are unremarkable .
    OUTPUT:
    
Small right pleural effusion and atelectasis right mid lung slightly improved since ___ .