In Vivo 31P MR Spectroscopy of Human Kidney Grafts Using the 2D-Chemical Shift Imaging Method

The aim of this work was to evaluate the possibility to use in vivo P-31 magnetic resonance spectroscopy (MRS) for the diagnosis of kidney graft dysfunction after transplantation. We examined 68 kidney grafted patients using a 1.5 T MR scanner. P-31 MRS was performed using the 2D-chemical shift imaging method. The patients were divided into 4 groups: acute rejection episode; acute tubular necrosis; late graft dysfunction; or good renal function. We measured the signal intensities of phosphomonoesters (PME), inorganic phosphate (Pi), phosphodiesters (PDE), and alpha-, beta-, gamma-adenosine triphosphate (ATP; with contributions of alpha- and beta-adenosine diphosphate) and their ratios. Patients with an acute rejection episodes showed a significantly elevated PME/beta-ATP and PDE/beta-ATP, PME/Pi, and PDE/Pi signal ratios compared with the control group. The group with acute tubular necrosis had decreased ratios. Patients with late graft dysfunction revealed only an insignificant decrease in PME/Pi and PDE/Pi ratios. We concluded that P-31 MRS was capable of distinguishing the two main causes of graft dysfunction early after transplantation.