Long-term assessment of posttransplant renal prognosis with P-31 magnetic resonance spectroscopy

Background. P-31-magnetic resonance spectroscopy (MRS) has been widely used to study pretransplantation. renal viability, and although some had discus sed posttransplant renal viability, no one has examined long-term posttrans plant renal prognosis. We discuss the use of P-31-MRS to assess the longter m prognosis from the time when MRS was performed. Methods. We studied 20 patients with renal allografts. 1.5 Tesla clinical m agnetic resonance imaging MRI) and 15 cm surface coil was used for P-31-MRS . Localized P-31-MRS was done using image selected in vivo spectroscopy (IS IS) method. Individual peaks were fitted by Lorenzian line-shapes with a le ast square method and peak area ratios were calculated. Results. A beta -adenosine triphosphate/inorganic phosphate (beta -ATP/Pi) ratio >1.2 had sensitivity of 92.8%, specificity of 100%, and accuracy of 9 5% for predicting 3-year renal survival; a beta -ATP/Pi ratio >1.2 had sens itivity of 90.9%, specificity of 66.7%, and accuracy of 76.9% for predictin g 5-year renal survival. We compared P-31-MRS spectra data between the surv ived group and failed group. The survived group had significantly higher be ta -ATP/Pi, alpha -ATP/Pi, and phosphodiester (PDE)/Pi ratios than the fail ed group. Conclusions. We discussed the beta -ATP/Pi value as a parameter for predict ing long-term survival of a transplanted kidney from the time when MRS was performed. A value above 1.2 suggests a high probability of 3-year renal su rvival, whereas a value over 2.5 indicates that the transplanted kidney cou ld survive over 5 years. P-31-MRS may be useful for predicting long-term su rvival of transplanted kidneys, but additional studies are needed.