Imaging of gastroenteropancreatic neuroendocrine tumors

Figure 11 Gallium 68 DOTATATE and Fluorine 18 fluorodeoxyglucose positron emission tomography/computed tomography of a patient with metastatic neuroendocrine carcinoma. A: Axial computed tomography (CT), fused DOTATATE positron emission tomography//CT (PET/CT) and fused fluorodeoxyglucose (FDG) PET/CT images of the brain. There is a focus of moderately increased DOTATATE uptake seen in the right occipital lobe (black arrow) associated with adjacent vasogenic edema, but no definite corresponding FDG uptake is seen; B: Axial CT, fused DOTATATE PET/CT and fused FDG PET/CT images of the thorax. There is an intensely FDG avid mass in the left upper lobe, but no corresponding DOTATATE tracer avidity is seen (white arrows), demonstrating an example of the “flip-flop” phenomenon secondary to tumor dedifferentiation; C: Axial CT, fused DOTATATE PET/CT and fused FDG PET/CT images of the abdomen. Again, there are intensely FDG avid lesions in the right liver lobe (white arrowheads) that do not demonstrate significant DOTATATE uptake, indicative of neuroendocrine tumor dedifferentiation.