Measurement of human skeletal muscle oxidative capacity by 31P-MR spectroscopy: a cross-validation with in vitro measurements

J Magn Reson Imaging. 2011 Nov;34(5):1143-50. doi: 10.1002/jmri.22733.


Purpose: To cross-validate skeletal muscle oxidative capacity measured by (31)P-MR spectroscopy with in vitro measurements of oxidative capacity in mitochondria isolated from muscle biopsies of the same muscle group in 18 healthy adults.

Materials and methods: Oxidative capacity in vivo was determined from PCr recovery kinetics following a 30-s maximal isometric knee extension. State 3 respiration was measured in isolated mitochondria using high-resolution respirometry. A second cohort of 10 individuals underwent two (31)P-MRS testing sessions to assess the test-retest reproducibility of the method.

Results: Overall, the in vivo and in vitro methods were well-correlated (r = 0.66-0.72) and showed good agreement by Bland Altman plots. Excellent reproducibility was observed for the PCr recovery rate constant (CV = 4.6%; ICC = 0.85) and calculated oxidative capacity (CV = 3.4%; ICC = 0.83).

Conclusion: These results indicate that (31)P-MRS corresponds well with gold-standard in vitro measurements and is highly reproducible.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Biopsy / methods
  • Cohort Studies
  • Female
  • Humans
  • Hydrogen-Ion Concentration
  • In Vitro Techniques
  • Knee / pathology
  • Magnetic Resonance Spectroscopy / methods*
  • Male
  • Middle Aged
  • Mitochondria / metabolism
  • Muscle, Skeletal / pathology*
  • Muscles / pathology
  • Oxidative Stress
  • Oxygen / metabolism
  • Phosphocreatine / analogs & derivatives*
  • Phosphocreatine / metabolism
  • Phosphorus Isotopes / pharmacology*
  • Reproducibility of Results


  • Phosphorus Isotopes
  • Phosphocreatine
  • phosphocreatinine
  • Oxygen