18F-FDG PET/CT (2-[fluorine-18] fluoro-2-deoxy-D-glucose, Positron emission tomography- CT) is a noninvasive technique that allows quantifying and precisely localizing 18F-FDG uptake in the entire body. 18F-FDG uptake is caused by increased local metabolic activity. Such increased uptake has been described not only in neoplastic lesions but also in inflammatory lesions. In this condition, uptake has been correlated with local stimulation of tumor necrosis factor, and with monocyte priming and activation. A physiologic variable uptake may be observed in the bowel, especially the cecum, and has limited the use of PET in inflammatory bowel diseases. The advantage of combined PET and CT devices lead to significant improvements in the interpretation of the bowel areas, and greatly reduces the number of false-positive findings in the gastrointestinal tract.