Altered biodistribution of FDG in patients with type-2 diabetes mellitus

Positron emission tomography-computed tomography (PET-CT) imaging of patients with diabetes can be problematic because elevated glucose levels may cause competitive inhibition of [F-18]-2-deoxy-2-fluoro-D-glucose (FDG) uptake in different tissues. Therefore, the aim of the study was to evaluate the biodistribution of FDG in patients with type-2 diabetes mellitus.

Two hundred forty patients were retrospectively enrolled to the study. Study population was divided into three subgroups, named as the normal (group 1), the insulin (group 2) and the oral anti-diabetic (group 3). Unenhanced low-dose CT and PET emission data were acquired from the mid-thigh to the vertex of the skull. FDG uptakes in different organs were evaluated qualitatively or semi-quantitatively.

In the diabetic groups, diffuse FDG uptake of the colon was increased (p > 0.001) but segmental FDG uptake was decreased (p > 0.001). Intestinal FDG uptake was detected in 20 % of the study population and only 3 % of these uptakes were in diffuse pattern. Segmental FDG uptake in the bowel was increased significantly in the groups of patients with diabetes (p = 0.002). Maximum standardized uptake values of the liver in the groups 1, 2, and 3 were 2.66 ± 0.6, 3.25 ± 0.9 and 3.16 ± 0.8, respectively, and the difference between the groups was not statistically significant (p = 0.083). Cardiac FDG uptake was decreased significantly in the groups of patients with diabetes (p < 0.001).

According to our results, whole body biodistribution of FDG uptake seems to be changed in patients with type-2 diabetes who were using insulin or oral antidiabetic drugs. Although the use of oral antidiabetic drugs was known to change the biodistribution of FDG, insulin use also seems to change FDG uptake in different organs of diabetic patients.