Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiomediastinal and hilar contours are normal , with calcification of the aortic arch . There is no pleural effusion or pneumothorax . The lungs are well expanded . A vague retrocardiac density , better seen on the lateral view , with hazy left retrocardiac density on the frontal view , may represent an infectious process . The upper abdomen is unremarkable .
    OUTPUT:
    
Vague left retrocardiac density may represent an infectious process . This result was emailed to the ED QA nurses by Dr . ___ on ___ at 8 :31 PM .