Examination of a myopathy by phosphorus nuclear magnetic resonance

A 16-year-old boy with myopathy, ophthalmoplegia, and raised basal metabolic rate was examined by the non-invasive technique of phosphorus-31 nuclear magnetic resonance (31 P NMR). The muscles of the forearm showed an abnormal 31P NMR spectrum with a high inorganic phosphate (Pi) content in relation to phosphocreatine (PCr) (PCr/Pi = 4; control = 10). This finding was compatible with the abnormality of mitochondrial function already established by biopsy and offers in addition an explanation for the raised oxygen consumption in this patient. The method of 31P NMR is suited to rapid non-invasive diagnosis in various muscle disorders.