Altered phosphate metabolism in myocardial infarction: P-31 MR spectroscopy

The high-energy myocardial phosphate metabolism of four patients with acute anterior myocardial infarction after coronary angioplasty and drug therapy was evaluated with cardiac-gated phosphorus magnetic resonance (MR) depth-resolved surface coil spectroscopy (DRESS) 5-9 days after the onset of symptoms. Significant reductions (about threefold) in the phosphocreatine (PCr) to inorganic phosphate (P(i)) ratio and elevations in the P(i) to adenosine triphosphate (ATP) ratio were observed in endocardially or transmurally derived MR spectra when compared with values from epicardially displaced spectra and values from epicardially displaced spectra and values from seven healthy volunteers (P < .05). High-energy phosphate metabolites and P(i) ratios did not vary significantly during the cardiac cycle in healthy volunteers. However, contamination of P(i) resonances by phosphomonoester components, including blood 2,3-diphosphoglycerate, precluded accurate spectral quantification of P(i) and pH. The results indicate that localized P-31 MR spectroscopy may be used to directly assess cellular energy reserve in clinical myocardial infarction and to evaluate metabolic response to interventions.