Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size remains mildly enlarged . Linear opacity within the right midlung likely represents a focus of scarring . Left basal opacity is again noted which could represent atelectasis , though difficult to exclude pneumonia . A small left pleural effusion is likely present . No pneumothorax . Mediastinal contour stable . Bony structures are intact .
    OUTPUT:
    
Left basal opacity , question atelectasis versus pneumonia . Likely small left effusion .