Absolute quantification of hepatic 31P metabolites at 3 T using a phantom replacement technique – How to set it up

Phantom replacement techniques for the quantification of absolute concentrations of hepatic phosphorous metabolites are an established tool for studying energy metabolism in vivo. However, many consideration need to be taken into account. Here, we present how to correct localized in vivo 31P-MRS data in order to report molar concentrations of ATP and inorganic phosphate and how to set up the experiments for obtaining the required correction factors. Correction factors include T1 correction, coil loading, excitation pulse profile as well as B1 inhomogeneity of the surface coil in all three spatial directions.