Assessment of gastrointestinal stromal tumors with computed tomography following treatment with imatinib mesylate

Figure 1 FP pattern. Contrast-enhanced CT of the abdomen obtained from a 39-year-old woman with metastatic GIST in the right lobe of liver. A: Before imatinib therapy, the lesion showed ill-defined thickened rim enhancement (arrow); B: After 2 mo therapy, a nearly complete cystic change and a thin lesion boundary were observed; C: After 5 mo therapy, a further decrease in size (partial response by RECIST) was seen; D: After 10 mo therapy, a small enhancing nodule was seen. Nodule within a mass or FP (arrow head).

Figure 2 GP pattern. Contrast-enhanced CT of abdomen obtained from a 55-year-old man with metastatic GIST in the mesentery. A: Before imatinib treatment, there were mesenteric masses (arrows); B: After 2 mo therapy, there was interval progression in both mesenteric masses, as demonstrated by increased tumor size and thickness of the enhancing wall (arrows).

Figure 3 NS pattern. Contrast-enhanced CT scan of abdomen obtained in a 39-year-old woman with metastatic GIST in the liver. A: Before imatinib treatment, a large subcapsular cystic lesion in the right hepatic lobe and a small amount of free fluid were noted; B: After 10 mo therapy, there were new, well-defined, homogeneous enhancing nodules adjacent to the gallbladder (arrow); C: After 13 mo therapy, there was a slight increase in size of the mentioned nodule (arrow).

Figure 4 GC pattern. Contrast-enhanced CT scan of the abdomen obtained in a 64-year-old man with metastatic GIST in both lobes of the liver (arrows). A: Before imatinib treatment, there were a few rather ill-defined, small homogeneous enhancing lesions in the liver (arrows); B: After 4 mo therapy, they showed better-defined, non-enhancing, low-density lesions; C: After 8 mo therapy, well-defined small cystic lesions with no interval change in size are noted.

Figure 5 NC pattern. Contrast-enhanced CT scan of abdomen in 50-year-old woman with metastatic GIST in the liver. A: Before imatinib treatment, no liver metastases were visible at this level; B: Contrast-enhanced CT after 2 mo treatment with imatinib. At least two non-enhancing low-density lesions were newly seen at the dome of the liver (arrows).

Figure 6 Overall survival after imatinib therapy, according to the patterns of CT change.