1. University of Oxford Centre for Clinical Magnetic Resonance Research, Radcliffe Department of Medicine (M.K.B., M.H., L.V., W.D.W., J.R., V.M.F., S.N., O.J.R., A.J.M.L.), University of Oxford, UK.
2. Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia (L.V.).
3. Department of Cardiology, Oxford University Hospitals NHS Foundation Trust, John Radcliffe Hospital, UK (J.R., N.S., S.N., O.J.R., A.J.M.L.).
4. Department of Physics, Clarendon Laboratory (J.J.M.), University of Oxford, UK.
5. The MR Research Centre and The PET Research Centre, Aarhus University, Denmark (J.J.M.)