1 From the Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kingshighway Blvd, Campus Box 8131, St Louis, MO 63110 (M.H.L.); Department of Radiology, Mayo Clinic at Scottsdale, Scottsdale, Ariz (K.S.Z.); and Medical Research Institute of New Zealand, Wellington, New Zealand, and Artibiotics, Wellington, New Zealand (C.K.).