Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There are bibasilar linear opacities , which were seen as early as ___ , suggestive of chronic scarring . The lungs are otherwise free of focal consolidations or pleural effusions . No evidence of pneumothorax . The heart and mediastinum are within normal limits . No osseous abnormalities are identified on this radiograph .
    OUTPUT:
    
Linear bibasilar scarring . No acute pulmonary abnormalities .