Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is normal in size . The mediastinal and hilar contours appear within normal limits . There is no pleural effusion or pneumothorax . A few ring shadows are again noted in the upper lungs , two on each side . Otherwise , the lung fields appear clear . Bony structures are unremarkable .
    OUTPUT:
    
No significant change in small pulmonary cystic structures . These could be seen with acute processes such as septic emboli , but could be seen with more chronic processes such as bronchiectasis , pneumatoceles , or potentially cavitating nodules associated with inflammatory processes such as Langerhans cell histiocytosis . Correlation with clinical findings is recommended .