Influence of fever on ¹⁸F-FDG PET/CT in vivo: Utilizing a quantitative parameter SUL

Fever can affect the identification and efficacy evaluation of tumors on the ¹⁸F-FDG PET/CT, and this effect can be reduced by referring to normal tissue metabolism. The aim of the study was to analyze the influence of fever on glucose metabolism in the mediastinal blood pool, liver, spleen, and bone marrow utilizing PET/CT quantitative parameter SUV normalized by lean body mass (SUL).

30 patients with fever of unknown origin and 24 patients for tumor screening with normal body temperature within 3 weeks, who underwent ¹⁸F-FDG PET/CT in our department, were analyzed retrospectively. The SUL_max and SUL_mean of the mediastinal blood pool, liver, spleen, and bone marrow were respectively measured in the two groups, and the differences between the two groups were compared by independent sample t test or Wilcoxon-Mann-Whitney test.

The SUL_max and SUL_mean of the liver in the fever group were lower than those in the control group (p = 0.001, 0.013). The SUL_max and SUL_mean of spleen and bone marrow in the fever group were higher than in the control group (all p < 0.05). The SUL_max of the mediastinal blood pool in the fever group was lower than that in the control group (p = 0.007), but there was no significant difference in SUL_mean of the mediastinal between the fever group and the control group (t = 1.181, p = 0.221).

The fever can affect the glucose metabolism in internal organs. But there was no significant difference in the SUL_mean of mediastinal blood pool. Perhaps the SUL_mean of the blood pool can be invoked as a calibration parameter in the evaluation of efficacy in tumor patients with fever.