Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is normal in size . The mediastinal and hilar contours appear within normal limits . There is an opacity in the posterior left lower lobe that obscures the hemidiaphragm suggesting pneumonia . Elsewhere , the lungs remain clear . There are no pleural effusions or pneumothorax . Mild degenerative changes are similar along the mid to lower thoracic spine .
    OUTPUT:
    
Findings consistent with pneumonia in the left lower lobe .