Assessment of in situ renal transplant viability by 31P-MRS: experimental study in canines.
In 14 in situ canine renal transplants, intracellular phosphorus metabolites were evaluated by phosphorus-31 magnetic resonance spectroscopy (31P-MRS), performed using surface coils to investigate the usefulness of this technique for assessing renal viability in situ. Group I control kidneys (n = 5) were autografts, as were Group II (n = 5) kidneys: the latter group were subjected to surgically induced vascular ischemia and thrombosis. Group III kidneys (n = 4) were rejecting allografts. Renal flow and function, as measured by 99mTc-DTPA, and findings on histologic examination were correlated with 31P-MRS spectra. Group I kidneys showed excellent viability on both 99mTc-DTPA studies and biopsy evaluation, and their 31P-MRS-derived ratios of phosphomonoesters/inorganic phosphate (PME/Pi) and adenosine triphosphate/Pi (ATP/Pi) were high (1.32 +/- 0.23 and 0.90 +/- 0.36, respectively). In contrast, Group II kidneys demonstrated poor flow and function, histologic evidence of severe ischemia from venous and arterial thrombosis, and significantly (P < 0.005) less viability than controls, as monitored by 31P-MRS PME/Pi (0.58 +/- 0.30) and ATP/Pi (0.20 +/- 0.13) ratios. Group III kidneys also demonstrated poor flow and function with 99mTc-DTPA, and the associated histologically injury was noted to be caused by accelerated rejection and severe vascular damage. PME/Pi (0.24 +/- 0.22) and ATP/Pi (0.10 +/- 0.01) ratios were also significantly (P < 0.005) less than those in controls, reflecting nonviability. The 31P-MRS-derived PME/Pi and ATP/Pi ratios enable a qualitative noninvasive assessment of blood flow-dependent renal viability, but with currently used localization techniques the differentiation between severe ischemia and severe acute rejection was not possible.
Department of Urology, University of California School of Medicine, San Francisco.
P N
PN
Bretan
D B
DB
Vigneron
H
H
Hricak
D C
DC
Price
T S
TS
Yen
J A
JA
Luo
E A
EA
Tanagho
T L
TL
James
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D004285:Dogs; D006084:Graft Rejection / Q000175:diagnosis; D006085:Graft Survival / Q000502:physiology*; D007668:Kidney / Q000378:metabolism* / Q000473:pathology; D016030:Kidney Transplantation / Q000502:physiology*; D009682:Magnetic Resonance Spectroscopy; D015609:Organotechnetium Compounds; D010710:Phosphates / Q000378:metabolism; D012078:Renal Artery Obstruction / Q000175:diagnosis; D004113:Succimer; D019783:Technetium Tc 99m Dimercaptosuccinic Acid; D016284:Technetium Tc 99m Pentetate; D013927:Thrombosis / Q000175:diagnosis
D015609:Organotechnetium Compounds; D010710:Phosphates; D019783:Technetium Tc 99m Dimercaptosuccinic Acid; D000255:Adenosine Triphosphate; D004113:Succimer; D016284:Technetium Tc 99m Pentetate