1. From the Department of Medical Imaging, The Ottawa Hospital, 1053 Carling Ave, Room C159, Ottawa, ON, Canada K1Y 4E9 (D.T.W., T.A.M., M.D.F.M., N.S.); Department of Radiology, University of Michigan Medical Center, Ann Arbor, Mich (M.S.D.); and Allergy and Immunology Associates of Ann Arbor PC, Ann Arbor, Mich (T.S.).