[What does 31 phosphorus magnetic resonance spectroscopy measure?A validation in healthy probands]

With 31P nuclear magnetic resonance spectroscopy skeletal muscle metabolism can be measured noninvasively. Aim of this study was to investigate intraindividual reproducebility, interindividual variability, and the correlation of the NMR parameters PCr, alpha-, beta-, gamma-ATP to graded exercise. Reproducebility and variability of PCr values were comparabel to changes of the pH value. Alpha-, beta-, gamma-ATP did not change during measurements. Correlations between the workload and the changes of the NMR parameters were rare. It was found that the intraindividual reproducebility is low and the interindividual variability is high. No systematic correlation between the NMR parameters and the workload could be seen. The termination of exercise in healthy volunteers is not explained by energy depletion but due to other mechanisms. There is no evidence that 31P NMR spectroscopy presents remarkable advantages for clinical purposes compared to well established diagnostic methods.