[Spectroscopy of phosphorus in nuclear magnetic resonance. General review of clinical applications to the study of human skeletal muscle].

Phosphorus nuclear magnetic resonance spectroscopy enables the energy metabolism of skeletal muscles to be studied non-invasively in vivo. Relative concentrations of phosphocreatine (PCr), inorganic phosphate (iP), monophosphoric sugars (mP) and ATP, as well as intracellular pH values, are directly accessible through the spectra. The striated muscle is continuously studied at rest, during exercise and during recovery. Exercise-induced changes in pH and mP provide indirect information on glycogenolysis and glycolysis. The speed of PCr resynthesis during post-exercise recovery and the PCr/iP ratio values at rest excellently reflect mitochondrial oxidative phosphorylations. Phosphorus NMR spectroscopy therefore is of interest not only to study the impact, through hypoxia, on muscle energy metabolism of such pathologies as cardiac or respiratory failure, or to study various acquired metabolic muscular diseases, but also and above all, to detect and locate muscular enzyme deficiencies involving glycogenolysis, glycolysis or mitochondrial metabolism, thereby pointing to the diagnosis of congenital, and mainly metabolic, myopathies.