Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is mildly enlarged . The mediastinal and hilar contours appear unchanged . Patchy opacification in the left mid lung suggests atelectasis or scarring , noting that it was already present and similar extent with a somewhat shifting morphology . There is no free air or pneumomediastinum .
    OUTPUT:
    
Similar patchy left mid lung opacity , probably due to atelectasis or scarring , noting the lack of change in absence of pulmonary symptoms . No evidence of free air or pneumomediastinum .