Impact of renal failure on F18-FDG PET/CT scans

Objectives The gold standard for F18-FDG PET/CT uptake times is currently 60 minutes for all oncology diagnoses with the exception of increasing to 90 minutes for malignancies with low FDG-avidity such as breast, hepatocellular, pancreatic and prostate cancers. However, the effects of renal failure on FDG PET/CT scans is unknown. It has been hypothesized that renal failure may reduce the uptake throughout the body and a longer uptake phase could be implemented to get a more accurate assessment. We aimed to determine if the uptake period for F18-FDG PET/CT studies should be lengthened from the standard 60 min in patients with renal failure. In order to do so, we quantified the impact renal failure had on the SUV max of the liver and psoas muscle.

Methods We retrospectively reviewed 1095 FDG PET/CT scans and kept a log of patients with a history of renal disease. Thirty patients were chosen with renal disease and of these, 12 were receiving dialysis. Thirty age and gender matched controls were chosen. BUN and Creatinine levels were recorded for all subjects. 30mm circular regions of interest were placed in the middle of the right hepatic lobe and the left psoas muscle just anterior of the iliac crest. The SUV max of both regions were recorded.

Results In the 30 renal disease patients, the mean SUV max for the liver (LSUV) is 2.77 and the mean of the psoas muscle (PSUV) is 1.43. The mean difference of -0.033 SUV max between renal disease patients compared to control group was statistically insignificant (p > 0.05). There were no significant differences found in LSUV and PSUV for dialysis and non-dialysis patients with renal disease (p > 0.05). In addition, gender and age did not have an impact on LSUV and PSUV.

Conclusions Renal disease has not been found to have an impact on uptake values on the internal reference points on FDG PET/CT studies. Therefore, patients with renal failure do not require an increased uptake phase and should remain at the standard 60 minutes. However, further review of dialysis schedules and the FDG distribution could help determine if there is a most appropriate time to receive dialysis to optimize the PET scan results.