The clinical implication and prediction of diffuse splenic FDG uptake during cancer surveillance

The purpose of this study was to investigate correlations between diffuse splenic FDG uptake and hematological and inflammatory parameters to clarify the significance of splenic FDG uptake on PET/CT images.

We retrospectively analyzed the consecutive records of F-18 FDG PET/CT scans and selected 31 patients with diffuse splenic FDG uptake as patient group. A total of 25 patients who underwent F-18 FDG PET/CT scans for simple health checkup were enrolled as control group. ROIs were placed on the liver and spleen to measure maximal standardized uptake value (SUVmax). The spleen SUVmax was divided by the liver SUVmax to calculate the spleen/liver ratio. The correlations between the S/L ratio and various hematological parameters were evaluated.

The S/L ratio was positively correlated with serum C-reactive protein level, white blood cell count, and neutrophil count and negatively correlated with hemoglobin, hematocrit, and red blood cell count. Under multiple regression analysis, the Hb level and the C-reactive protein level were the significant predictors for diffuse splenic FDG uptake.

In conclusion, our study suggests that concurrent inflammation or anemia at the time of PET/CT study could be one of various causes of diffuse splenic FDG uptake.