Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral chest radiographs demonstrate slight increase in size of left lower lung airspace opacity with increased retrocardiac component . The lungs are otherwise clear , the cardiac silhouette is normal . The mediastinal contours are unremarkable . Pulmonary vasculature is normal .
    OUTPUT:
    
Slight interval increase in left lower lung opacity compatible with slightly worsening pneumonia .