Figure 1.

A time-series of stacked ¹³C spectra (bottom) show the immediate appearance of pyruvate and pyruvate-hydrate signal, followed by lactate and alanine. The unidentified peaks are impurities from the hyperpolarized pyruvate sample, and not indicative of biological activity. The time-evolution of signal levels is very similar between control and inflammatory groups, with the exception of the lactate signal, which is significantly increased in the diseased cohort. This can be seen in the three overlaid spectra, which are averages of the ten spectra between 20 and 30 seconds after the end of the hyperpolarized injection (top). The 7-day inflammatory model spectrum (red) is visually indistinguishable from the 21-day (blue) and control (green) spectra, except at the position of the lactate peak; at this position, the 21-day peak area exceeds that of the control by approximately a factor of two, and the 7-day exceeds the control by approximately a factor of three.