Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are hyperexpanded . A new opacity seen within the posterior sulcus on the lateral view , overlying the spine . There is no pneumothorax or pleural effusion . The heart remains mildly enlarged . The hilar structures are unremarkable . Calcifications are noted within the aortic arch . A moderate sized hiatal hernia is stable . An old right scapular fracture is unchanged .
    OUTPUT:
    
Posterior basilar opacity is likely pneumonia in the ___ clinical setting . Follow up radiograph is recommended after treatment to document resolution .