Usefulness of low dose oral contrast media in 18F-FDG PET/CT

The standard protocol using large volume of oral contrast media may cause gastrointestinal discomfort and contrast-related artifact in PET/CT. The aim of this study was to evaluate the usefulness of low dose oral contrast in 18F-FDG PET/CT. We retrospectively reviewed a total of 435 PET/CT images. About 200 ml of oral contrast agent was used immediately before injection of F-18 FDG. The FDG uptake of intestines was analyzed by visual and semi-quantitative method on transaxial, coronal and sagittal planes. Seventy patients (16%, 113 sites) showed high FDG uptake; 50 (74%, 84 sites) with diffuse uptake and 20 (26%, 29 sites) with focal uptake. The most commonly delivered site of oral contrast media was small bowel (n=27, 39%). On PET/CT images, FDG uptake coexisted with oral contrast media in 26 patients (54%, 38 sites) with diffuse pattern and 9 (45%, 9 sites) with focal pattern, and, by site, those were 38(45%) and 9(31%), respectively. In small bowel regions, the proportion of coexistence reached as high as 61% (29/47 sites). We concluded that application of low dose contrast media can be helpful in the evaluation of intestinal uptake in FDG PET/CT images