1. From the Department of Radiology (A.K.N., S.P.S., K.T.F., S.K.V., J.P.H., M.L.W., E.C.E., J.M.B., J.G.F., M.C.O., J.L.F.) and Division of Gastroenterology and Hepatology (A.E.B., D.A.K.), Mayo Clinic, 200 1st St SW, Rochester, MN 55905; and Department of Radiology, Mayo Clinic, Scottsdale, Ariz (C.D.J.).