In vivo detection of 13C isotopomer turnover in the human brain by sequential infusion of 13C labeled substrates

► Feasibility of 13C isotopomer MRS of human brain is demonstrated. ► [U-13C6]glucose and [2-13C]glucose generate doublets and singlets of brain amino acids, respectively. ► Different 13C labeling pathways are simultaneously detected in the human brain at 3 T.