Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: In comparison with chest radiograph from ___ , a small area of heterogeneous opacity in the posteroinferior aspect of the left lower lobe suggests pneumonia . There is no effusion or pneumothorax . Mediastinal and hilar contours are normal . Heart size is normal .
    OUTPUT:
    
Probable small left lower lobe pneumonia . Recommend follow - up chest radiograph in ___ weeks following antibiotic therapy to assess resolution .