1. From the Department of Radiology (S.M.H., A.M.N., J.P.C., D.A.L.), Division of Biostatistics and Bioinformatics (M.J.S.), and Department of Medicine (J.D.C.), National Jewish Health, 1400 Jackson St, Denver, CO 80206-2761; and Channing Division of Network Medicine, Brigham and Women’s Hospital, Boston, Mass (E.K.S.).