1. Section of Investigative Medicine (C.N.J., A.A., A.N.C., R.R., A.D.S., G.M.K.N., Z.G.-D., M.A.G., S.R.B., W.S.D.), Imperial College London, Hammersmith Hospital, London W12 ONN, United Kingdom;
2. Endocrine Research Unit (J.D.V.), Center for Translational Science Activities, Mayo Clinic, Rochester, Minnesota 55905;
3. Department of Imaging (A.M., C.T.), Imperial College Healthcare National Health Service Trust, Charing Cross Hospital, London W6 8RF, United Kingdom