Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP portable upright view of the chest . There is subtle retrocardiac opacity which in the correct clinical setting may represent pneumonia . Lateral view may aid in diagnosis . No large effusion or pneumothorax . No convincing signs of edema . Heart size is normal . Mediastinal contours unremarkable . Bony structures appear intact .
    OUTPUT:
    
Subtle retrocardiac opacity , question pneumonia . Lateral view would be helpful to further assess .