Figure 13.

Two cases of GIST tumor. Case 1 (a,b): Hepatic GIST metastatic disease before and after successful treatment with Imatinib. (a) Pretreatment axial FDG PET-CT shows hypermetabolic mass in the right lobe of the liver (white arrowhead); (b) Post treatment axial fused FDG PET-CT image show resolution of metabolic activity with treatment (white arrowhead). Complete metabolic response means disease control, not complete pathologic response; Case 2 (c,d): Large gastric GIST tumor before and after treatment with imatinib. (a) Pretreatment axial FDG PET-CT shows a large, centraly necrotic, peripherally hypermetabolic tumor arising from the stomach (white arrow); (b) Post-treatment axial FDG PET-CT shows that the tumor has increased both in size and metabolic activity (white arrow), consistent with lack of tumor control.