1. From the Department of Radiology, University of Southern California, Keck School of Medicine, Keck Hospital, 1500 San Pablo St, 2nd Floor, Suite 2250, Los Angeles, CA 90033 (M.W.Y., L.H.L.); Department of Biostatistics, Avania U.S., Marlborough, Mass (J. Perez); and Department of Radiology, The University of Chicago, Chicago, Ill (A.V.E., J. Papaioannou, Y.J.).