Alternative 1-(13)C glucose infusion protocols for clinical (13)C MRS examinations of the brain.

Clinical utility of (13)C MRS is limited by cost and long examination times. Three 1-(13)C glucose infusion protocols-a high-dose i.v., low-dose i.v., and oral administration of 1-(13)C glucose-were compared on a GE 1.5T MR scanner. Resolution and sensitivity were sufficient to identify (13)C glucose (1alpha and 1beta), glutamate (C1-C4), glutamine (C1-C4), aspartate (C2 and C3), lactate, alanine, and bicarbonate in brain spectra. The three protocols were efficacious, as measured by cerebral enrichment of 1-(13)C glucose (62%, 42%, and 38%) and its principal metabolite, 4-(13)C glutamate (13%, 11%, and 16%), respectively. Intravenous infusion of 1-(13)C glucose 0.23 g/kg body weight (low dose) provides equivalent information at one third the cost of previous regimes. Magn Reson Med 46:39-48, 2001.