Test-retest repeatability of quantitative organ and tissue uptake using 20-minute dynamic multiparametric whole-body [F]FDG PET/CT in patients with type 2 diabetes.

BACKGROUND

Recently developed dynamic whole-body PET/CT (D-WB PET/CT) protocols allow for measurements of potentially more precise metabolic parameters than the commonly used semiquantitative SUV. Most notable is the metabolic rate of FDG uptake (MR), which reflects quantitative glucose uptake into tissues and organs. However, data on the reproducibility of MR measurements are scarce, particularly in patients with perturbed glucose homeostasis such as type 2 diabetes. We therefore aimed to evaluate the test-retest repeatability of both MR and SUV in these patients.

RESULTS

Fifteen participants (mean age 71 ± 7 years; 2 females) with type 2 diabetes underwent a short 20-minute [F]FDG D-WB PET/CT after 6 h fasting on two consecutive days. Both SUV and MR images were reconstructed from D-WB PET/CT data obtained 60-80 min post-injection of [F]FDG. MR and SUV data were measured in organs and tissues, and repeatability was assessed with Bland-Altman analysis, intraclass correlation coefficients (ICC), repeatability coefficients (RPC) and coefficients of variation (wCV). There was high repeatability of both SUV and MR in all measured organs (ICC range: 0.65-0.95 for SUV and 0.66-0.94 for MR). SUV generally demonstrated higher reliability (ICC) and lower variability (%RPC and %wCV) when compared to MR. However, MR test-retest variation was < 19% in most analysed tissues, demonstrating that MR may be used as a precise marker of treatment response.

CONCLUSION

This study demonstrates that MR calculated from D-WB PET/CT exhibit high repeatability, comparable to SUVs across most organs in patients with type 2 diabetes.