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

Validation and improvements to the proton MR spectroscopic measurement of creatine and phosphocreatine in vivo at 3 T.

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.

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.

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.