Quantification of Undecoupled 13 C NMR Spectra in the Brain

13 C spectra using LCModel with prior knowledge of chemical shifts and J-coupling values. The use of prior information on J-coupling and fitting the multiplets simultaneously in the LCModel improves accuracy of quantification so that errors in the quantification is significantly less than the loss in peak S/N suffered in the absence of decoupling. Using this approach the experimental setup can be simplified by alleviating constraints imposed on electrical isolation between 13 C and 1 H RF channels and the use of RF filters. Human studies are restricted at high fields due to SAR limitation imposed by RF decoupling and also the inhomogeneous B1 field distribution which precludes the exact determination of the local SAR level in the brain due to subjects' anatomical variability. Therefore the proposed technique of acquiring undecoupled 13 C spectra is a safer approach since power deposition is significantly reduced. Furthermore some of the signal loss when not applying decoupling can be recovered by reducing the repetition time. In addition data could be collected anywhere in the brain without risk of damaging low-perfused tissues such as the eyes. In conclusion, the methodology of acquiring 13