[1] MRC Cyclotron Unit, Hammersmith Hospital, London, United Kingdom
[2] Division of Cardiovascular Diseases and Internal Medicine, Mayo Clinic, Mayo Foundation, Rochester, MN, United States
[3] Department of Nuclear Medicine, Mayo Clinic, Mayo Foundation, Rochester, MN, United States
[4] Department of Physiology, Mayo Clinic, Mayo Foundation, Rochester, MN, United States
[5] MRC Cyclotron Unit, Hammersmith Hospital, Du Cane Road, London, W12 ONN, United Kingdom