Overestimation of cardiac lactate production caused by liver metabolism of hyperpolarized [1‐13C]pyruvate

Purpose The purpose of this work was to study the contribution of liver [1‐13C]lactate to the lactate signal detected in the heart following injection of hyperpolarized [1‐13C]pyruvate. Methods A slice‐selective saturation scheme was incorporated into a hybrid metabolic imaging and spectroscopy approach to selectively presaturate lactate in the liver. Imaging and slice‐selective spectroscopy of [1‐13C]pyruvate and its downstream metabolites were sequentially interleaved in the same experiment with optional presaturation of liver [1‐13C]lactate. Six healthy rats were measured, and metabolic data in the heart acquired with and without presaturation of liver lactate were compared. Results When using liver lactate presaturation, a statistically significant reduction of the lactate/pyruvate ratio was observed in the spectroscopic data of the left ventricle (0.18 ± 0.03 versus 0.24 ± 0.04; p