1 Department of Radiology, Section of Vascular and Interventional Radiology, Northwestern University, 676 N. St. Clair, Suite 800, Chicago, IL 60611. Electronic address: [email protected].
2 Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University, Medicine, Stanford, CA.
3 Division of Gastroenterology and Hepatology, Department of Medicine, University of California at San Francisco, San Francisco, CA.
4 Division of Interventional Radiology, Department of Radiology, Stanford University, Stanford, CA.