Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac , mediastinal and hilar contours are normal . The pulmonary vasculature is not engorged . Focal opacity within the left upper lobe is concerning for pneumonia . The right lung is clear . No pleural effusion or pneumothorax is present . No acute osseous abnormality seen .
    OUTPUT:
    
Findings concerning for pneumonia within the left upper lobe . Followup radiographs after treatment are recommended to ensure resolution of this finding .