Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size is mildly enlarged but unchanged . The mediastinal and hilar contours are within normal limits . The pulmonary vasculature is normal . Patchy opacity within the left lower lobe is concerning for pneumonia . Right lung is clear . No pleural effusion or pneumothorax is identified . There are no acute osseous abnormalities .
    OUTPUT:
    
Left lower lobe pneumonia . Follow up radiographs after treatment are recommended to ensure resolution of this finding .