The NMR measurements were carried out at 14.1 T, and the fumarate 1-13 C 𝑇 was 27.5 s. The dominant relaxation mechanism is chemical shift anisotropy , which means a markedly longer 13 C 𝑇 is expected by working at lower magnetic field. This is an exciting perspective for future applications of [1-13 C]fumarate in clinical imaging scanners, which typically employ field strengths of 1-3 T.