Abstract #0319

Improved Quantification of Mitochondrial Exchange, TCA Cycle Rate and Neurotransmission Flux Using 1H{13C} MRS Measurements of C4 and C3 of Glutamate and Glutamine

Bernard Lanz¹, Lijing Xin¹, Rolf Gruetter^1,2

¹Laboratory for functional and metabolic imaging, Ecole Polytechnique Fdrale de Lausanne, Lausanne, Switzerland; ²Departments of Radiology, Universities of Lausanne and Geneva, Lausanne and Geneva, Switzerland

[2-¹³C]acetate infusion coupled with ¹³C MRS enables the separated assessment of glial and neuronal Krebs cycle fluxes with higher accuracy than ¹³C labeled glucose, due to the asymetric metabolism of acetate in the brain. However, the faster neuronal Krebs cycle induces a strong dilution of the ¹³C labeled glutamate on the neuronal side, resulting in lower ¹³C MRS signal than with glucose. In this study, we analyzed with Monte-Carlo simulations the precision of the fitted metabolic fluxes with separated GluC3/GlnC3 curves obtained with ¹H{¹³C} MRS as well as the impact of the neuroglial partition of glutamate on the fluxes.