Differentiating Creatine and Phosphocreatine In Vivo Using 3 T ¹ H MR Spectroscopy

Purpose Validation and improvements to the proton MR spectroscopic measurement of creatine and phosphocreatine in vivo at 3 T. Methods Spectral simulations were used to evaluate and explore the mitigation of LCModel fitting bias due to lineshape, signal‐to‐noise (SNR) and non‐metabolite backgrounds with a focus on phosphocreatine and the spline regularization settings in the fitting model. Results Although phosphocreatine and creatine are visually unresolved, excellent fitting estimates are achieved in the absence of non‐metabolite background using default settings. However, in the presence of non‐metabolite background, bias is observed and depends on lineshape, SNR and differences in the non‐metabolite background. A more flexible setting for the LCModel spline largely mitigates this bias, allowing for the confidence to use proton MRS for PCr dynamic studies. Conclusion Without prior knowledge of the non‐metabolite signal, default settings of LCModel can introduce significant bias. Modified setup for LCModel improves quantitation of phosphocreatine and reduces bias in the overall set of metabolites.