Simultaneous Detection of Metabolism of Different Substrates in the Carboxylic/amide Region Using in Vivo 13C MRS

Yun Xiang¹, Jun Shen¹

In the carboxylic/amide region, brain ¹³C signals can only have one one-bond ¹³C-¹³C homonuclear coupling. As such only doublets (with a ¹³C-¹³C coupling of ~50 Hz) and singlets exist in this region. The large one-bond ¹³C-¹³C J coupling and the lack of interference from other isotopomers provide a unique condition for simultaneous detection of metabolism of different substrates. Examples of co-infusion of [¹³C₆]-D-glucose and [1-¹³C] acetate as well as co-infusion of [¹³C₆]-D-glucose and [1,3-¹³C₂] hydroxybutyrate are shown to demonstrate in vivo simultaneous detection of different metabolic pathways in the brain using ¹³C MRS of the carboxylic/amide region.