Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP upright and lateral chest radiographs were obtained . Lung volumes are low . A retrocardiac opacity projects over the spine on the lateral view . No effusion or pneumothorax is present . The heart and mediastinal contours are normal . The lower edge of cervical pedicular screws is present .
    OUTPUT:
    
Left lower lobe pneumonia .