Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Linear retrocardiac opacity is seen and could potentially represent atelectasis however infection is not entirely excluded . Multiple previously seen calcified conglomerate lymph nodes in the mediastinum and left hilum as seen on prior studies . There is no effusion , or pneumothorax . No evidence of cardiomegaly . Imaged osseous structures are intact . No evidence of free air below the diaphragm .
    OUTPUT:
    
1 . Linear retrocardiac opacity is seen and could potentially represent atelectasis however infection is not entirely excluded . 2 . Multiple stable calcified conglomerate lymph nodes in the mediastinum and left hilum .