RAT GLIOMA LACTATE TURNOVER: MEASURED BY IN VIVO NMR SPECTROSCOP: BRAIN NEOPLASM

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In the past two years, we focused on exploring and establishing the feasibility of broadband proton decoupling and evaluating 13C spectroscopy at 4 Tesla. A novel coil design, that has allowed us to decouple at power levels below those reported at 1.5 Tesla was introduced and we demonstrated in human muscle, the detection of narrow resonances (2-4 Hz linewidth) from natural abundance glutamate, creatine, choline, and taurine. We established full three-dimensional localization of 13C MRS using polarization transfer based on which we dubbed Proton Excited Carbon-13 Image Selected in vivo Localized spectroscopy, PRECISELY. We demonstrated the successful three-dimensional localization in the human brain at 4T via the elimination of all scalp lipid signals and documented significant sensitivity increases at 4T (~ factor 5) over those previously reported at 2.1 Tesla. Metabolite peaks had linewidths that were as low as 2-3 Hz in the human brain, which is essentially the same as those reported at lower fields. 13C MRS was also used in conjunction with 1H MRS to assign an unusually high peak to scyllo-inositol in the normal human brain by detecting an elevated intensity at 74.5 ppm.