Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is been interval placement of a left internal jugular central venous catheter which terminates in the expected location of the left brachycephalic vein . No pneumothorax . Mediastinal contour is flatter than on previous examination the cardiac silhouette is unchanged . No pleural effusions .
    OUTPUT:
    
1 . Post left internal jugular central venous catheter placement which terminates in the expected location of the left brachycephalic vein . No pneumothorax . 2 . Apparent interval widening of the mediastinum raises the possibility of mediastinal hematoma or aortic injury . If there is any clinical concern , contrast enhanced CT of the chest should be obtained for further evaluation .