Proton MR spectroscopy of wild-type and creatine kinase deficient mouse skeletal muscle: Dipole-dipole coupling effects and post-mortem changes

Localized proton MR spectra of mouse skeletal muscle obtained at 7 T show d ipole-dipole coupling effects for creatine and putative taurine resonances and for the lactate methine signal. These effects are independent of the pr esence of creatine kinase. The intensity of the methylene H-1 resonance of creatine is not different between wild-type and creatine kinase deficient m ice, which have a lower phosphocreatine content. H-1-MR spectra acquired po st-mortem from wild-type mouse skeletal muscle parallel to B-0 show a linew idth decrease for the methyl resonance of creatine and a 20% signal intensi ty loss for its methylene peak concurrent with the total breakdown of phosp hocreatine as observed by P-31-MR spectroscopy. However, with the muscle at the magic angle no changes in the appearance and intensity of creatine (an d taurine) resonances are observed. These results indicate that the changes observed for creatine resonances are related to altered dipolar couplings and that the intensity of the methylene peak does not necessarily reflect m uscular phosphocreatine content. (C) 2000 Wiley-Liss, Inc.