Figure 5.

¹³C NMR spectra from a mouse tumor in vivo at 7.0 T following i.v. injection of hyperpolarized [1,2-¹³C₂]pyruvate, acquired (a) immediately following injection (∼18 s after dissolution), (b) after maintaining the animal for ∼7 s at ∼40 mT after injection and (c) following injection of hyperpolarized pyruvate prepared with negative singlet order (∼30 s after dissolution; the longitudinal magnetization of the sample was destroyed by shaking the hyperpolarized substrate in a mu-metal chamber immediately after dissolution). In all three experiments the spectra were acquired with a single scan.