1 Division of Abdominal Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Radiology Administration, WHT 270, Boston, MA 02114, USA. Electronic address: ocatalano@mgh.harvard.edu.
2 Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Radiology Administration, AUS-210, Boston, MA 02114, USA. Electronic address: msgee@mgh.harvard.edu.