Effects of fasting on serial measurements of hyperpolarized [1‐(13)C]pyruvate metabolism in tumors

Imaging of the metabolism of hyperpolarized [1‐(13)C]pyruvate has shown considerable promise in preclinical studies in oncology, particularly for the assessment of early treatment response. The repeatability of measurements of (13)C label exchange between pyruvate and lactate was determined in a murine lymphoma model in fasted and non‐fasted animals. The fasted state showed lower intra‐individual variability, although the [1‐(13)C]lactate/[1‐(13)C]pyruvate signal ratio was significantly greater in fasted than in non‐fasted mice, which may be explained by the higher tumor lactate concentrations in fasted animals. These results indicate that the fasted state may be preferable for the measurement of (13)C label exchange between pyruvate and lactate, as it reduces the variability and therefore should make it easier to detect the effects of therapy. © 2016 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd.