Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A left PICC is likely terminates at the confluence of the brachiocephalic vein and SVC . Increased retrocardiac opacity and apparent leftward mediastinal shift suggests increasing left lower lobe atelectasis . Otherwise , no significant change compared to 2 hours prior .
    OUTPUT:
    
1 . A left PICC likely terminates at the confluence of the left brachiocephalic vein and SVC . 2 . Increased retrocardiac opacity and apparent leftward mediastinal shift suggests increasing left lower lobe atelectasis . Superimposed infection can not be ruled out . Recommend follow - up radiographs ensuring optimum patient positioning .