Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiac silhouette size is normal . Mediastinal and hilar contours are unchanged . Pulmonary vasculature is not engorged . Patchy opacity within the retrocardiac region is concerning for pneumonia . Right lung is clear . No pleural effusion or pneumothorax is seen . No acute osseous abnormality is detected .
    OUTPUT:
    
Patchy retrocardiac opacity concerning for pneumonia .