Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are normally expanded . There is a rounded opacity at the right base . The lung fields are otherwise clear . There is no pleural effusion or pneumothorax . The cardiomediastinal silhouette , hilar contours and pleural surfaces are normal . There is calcification of aortic arch .
    OUTPUT:
    
Opacity at the right base may reflect pneumonia . Please obtain followup radiographs after treatment in approximately 6 weeks .