Purpose: Physiological FDG uptake in the stomach is a common phenomenon, especially noted at the cardia. Water intake just before scanning will result in gastric distention and thinning of the gastric wall, which in turn may lead to a reduction in the physiological uptake in the gastric wall. In the current study, we investigated whether gastric distention by water intake just before PET imaging reduces physiological FDG uptake in the stomach.
Methods: The patient population comprised 60 patients who underwent whole-body FDG-PET imaging for cancer screening following gastroscopy performed within the preceding week. All patients took 400 ml of water for hydration and were administered 185 MBq of FDG intravenously. The patients were randomly divided into two groups: a group with additional water intake (AW group; n = 30) and a group without additional water intake (NW group; n = 30). In the AW group, an additional 400 ml of water was given just before PET imaging. For quantitative analysis, the stomach was classified into three areas [upper (U), middle (M) and lower (L)], and the degree of FDG uptake in each area was evaluated using standardised uptake values (SUVs).
Results: In the NW group, the mean SUVs in the U, M and L areas were 2.41 +/- 0.75, 2.28 +/- 0.73 and 1.61 +/- 0.89, respectively, while in the AW group they were 1.82 +/- 0.66, 1.73 +/- 0.56 and 1.48 +/- 0.49, respectively, and 2.21 +/- 0.38 in the oesophago-gastric junction. The mean SUVs in the U and M areas in the AW group were significantly lower than those in the NW group (p < 0.05).
Conclusion: Additional water intake just before PET imaging is an effective method for suppressing physiological FDG uptake in the stomach.