1. Department of Radiology, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA
2. Harvard Medical School, Boston, MA 02215, USA
3. Department of Surgery, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA
4. Boston University Chobanian & Avedisian School of Medicine, 72 East Concord Street, Boston, MA 02118, USA