Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral chest radiographs demonstrate a tunneled right IJ dialysis catheter tip terminating in the right atrium . There is a subtle retrocardiac opacity seen best on the lateral view . There is no pleural effusion or pneumothorax . The heart size is normal .
    OUTPUT:
    
Subtle left retrocardiac opacity may represent pneumonia in the proper clinical setting .