Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP and lateral chest radiograph demonstrates surgical clips which project over the left mediastinal border and centrally over the heart . Heart size is normal . There is no pleural effusion or pneumothorax . Density in the retrocardiac region seen only on the lateral view in the appropriate clinical setting could reflect developing pneumonia . There is no evidence of pulmonary edema . Imaged upper abdomen demonstrates no air under the right hemidiaphragm .
    OUTPUT:
    
In the appropriate clinical setting , density in the retrocardiac region could reflect developing pneumonia .