Phosphorus-31 (31P) magnetic resonance spectroscopy of the kidneys promises to provide metabolic information leading to better assessment of renal physiology. However, the problems of studying the metabolism of the heterogeneous renal architecture by precisely localizing the origin of the signal obtained from small voxels and eliminating motion artifacts have not been solved as yet. The normal 31P MRS spectra show a characteristic fingerprint of six peaks including phosphomonoesters, phosphodiesters, inorganic phosphorus, and gamma, alpha, beta adenosine triphosphate (ATP). Renal failure, regardless of its etiology and mechanism of inducement (hypoxia, ischemia, acidosis, or obstruction) produces a loss of ATP with a progressive increase of inorganic phosphorus and a decline in intracellular pH. The severity of renal failure correlates with the severity of the metabolic disturbance. The potential use of 31P MRS in the assessment of renal viability has been applied to the study of renal preservation methods and prediction of renal function following transplantation.
