Radioembolization-Induced Changes in Hepatic [18F]FDG Metabolism in Non-Tumorous Liver Parenchyma

Background: [F-18]FDG-PET/CT is increasingly used for response assessments after oncologic treatment. The known response criteria for [F-18]FDG-PET/CT use healthy liver parenchyma as the reference standard. However, the [F-18]FDG liver metabolism results may change as a result of the given therapy. The aim of this study was to assess changes in [F-18]FDG liver metabolism after hepatic Y-90 resin radioembolization. Methods: [F-18]FDG-PET/CT scans prior to radioembolization and one and three months after radioembolization (consistent with the PERCIST comparability criteria), as well as Y-90-PET/CT scans, were analyzed using 3 cm VOIs. The FDG activity concentration and absorbed dose were measured. A linear mixed-effects logistic regression model and logistic mixed-effects model were used to assess the correlation between the FDG-activity concentration, absorbed dose, and biochemical changes. Results: The median SULVOI,liver at baseline was 1.8 (range = 1.2-2.8). The mean change in SULVOI,liver per month with an increase in time was 0.05 (95%CI 0.02-0.09) at p < 0.001. The median absorbed dose per VOI was 31.3 Gy (range = 0.1-82.3 Gy). The mean percent change in Delta SULVOI,liver for every Gy increase in the absorbed dose was -0.04 (95%CI -0.22-0.14) at p = 0.67. The SULblood and SULspleen results showed no increase. Conclusions: The [F-18]FDG metabolism in the normal liver parenchyma is significantly but mildly increased after radioembolization, which can interfere with its use as a threshold for therapy response.

Automated summary

The aim of this study was to assess changes in [F-18]FDG liver metabolism after hepatic Y-90 resin radioembolization. The study found that the [F-18]FDG metabolism in the normal liver parenchyma is significantly but mildly increased after radioembolization, which can interfere with its use as a threshold for therapy response.