Preliminary study comparing diffuse gastric FDG uptake and gastritis.

Diffuse high FDG uptake in the stomach is occasionally observed on positron emission tomography (PET) images. Some PET oncologists believe this to be physiologic uptake, but the exact cause is undetermined. We retrospectively compared PET images and endoscopic findings to examine the relation between diffuse gastric FDG uptake and gastritis. From September to December 2005, 113 individuals (68 men and 45 women), aged 52 ± 12 years, underwent both gastrofiberscopy and PET/computed tomography on the same day as part of a cancer screening program. Gastric FDG uptake was visually evaluated on PET images and classified as low, moderate, or high. Gastritis was classified as mild, moderate, or severe. For each screenee, the degree of FDG uptake was compared with the severity of gastritis. FDG uptake was low, moderate, and high in 64, 31, and 18 screenees, respectively. Gastritis was mild, moderate, and severe in 59, 44, and 10 screenees, respectively. A significant relation was observed between the degree of FDG uptake and the degree of gastritis (p＜0.0001). High FDG uptake was observed significantly more often in the upper half of the stomach than in the lower half (p＜0.0001). Similarly, gastritis was observed significantly more often in the upper half of the stomach (p=0.005). A significant relation was observed between the degree of FDG uptake and the severity of gastritis in both the upper (p＜0.0001) and lower (p=0.01) portions. In conclusion, the significant relation we found between the degree of FDG uptake and the severity of gastritis suggests that gastritis is a major cause of diffuse FDG uptake in the stomach.