DOI: 10.1148/rg.262055097
Gastrointestinal Stromal Tumor: Role of CT in Diagnosis and in Response Evaluation and Surveillance after Treatment with Imatinib1
Xie Hong, MD, PhD,
Haesun Choi, MD,
Evelyne M. Loyer, MD,
Robert S. Benjamin, MD,
Jonathan C. Trent, MD, PhD and
Chusilp Charnsangavej, MD
1 From the Departments of Diagnostic Radiology (X.H., H.C., E.M.L., C.C.) and Sarcoma Medical Oncology (R.S.B., J.C.T.), Unit 57, University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX 77030. Recipient of a Certificate of Merit award for an education exhibit at the 2004 RSNA Annual Meeting. Received April 14, 2005; revision requested May 11 and received July 11; accepted July 11. H.C. and R.S.B. are consultants to and J.C.T. has received a research grant from the speakers bureau of Novartis Pharma, Basel, Switzerland; all other authors have no financial relationships to disclose.
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Figure 1. Gastric GIST in a 68-year-old woman who presented for an annual checkup with mild epigastric discomfort. The diagnosis was made with CT-guided biopsy. Contrast-enhanced CT scan shows a homogeneous extraluminal mass (arrow) arising from the greater curvature of the stomach. This appearance is typical of primary GIST. A subtotal gastrectomy was performed; there was no evidence of recurrence 18 months after surgery. The patient is currently undergoing surveillance.
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Figure 2. Gastric GIST in a 67-year-old man with rectorrhagia. A diagnosis of chronic gastritis was made at endoscopic biopsy. Contrast-enhanced CT scan shows an exophytic, slightly enhancing soft-tissue mass (long arrow) arising from the lesser curvature of the stomach. The oral contrast material (arrowheads) within the ulcerated mass is due to a fistula to the gastric lumen. To make the diagnosis, biopsy of one of the hepatic metastases (short arrows) was performed.
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Figure 3. Gastric GIST in a 72-year-old man with weakness. The diagnosis was made with exploratory laparotomy. Contrast-enhanced CT scan shows an unresectable gastric mass (arrowheads) completely surrounding the stomach. There is a small amount of contrast material (arrow) within the mass because of a fistula to the gastric lumen. Results of the initial endoscopic biopsy were negative for malignancy.
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Figure 4a. Small gastric GIST in a 42-year-old woman with Hodgkin lymphoma. The mass was detected at routine follow-up and diagnosed with endoscopic biopsy. (a) Contrast-enhanced CT scan shows a small (1.5-cm), exophytic mass (arrow) near the gastroesophageal junction. (b) Follow-up CT scan obtained 2 years later shows that the mass (arrow) has increased in size.
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Figure 4b. Small gastric GIST in a 42-year-old woman with Hodgkin lymphoma. The mass was detected at routine follow-up and diagnosed with endoscopic biopsy. (a) Contrast-enhanced CT scan shows a small (1.5-cm), exophytic mass (arrow) near the gastroesophageal junction. (b) Follow-up CT scan obtained 2 years later shows that the mass (arrow) has increased in size.
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Figure 5. Small bowel GIST in a 55-year-old woman who had abdominal discomfort but was otherwise healthy. The diagnosis was made with CT-guided biopsy. Contrast-enhanced CT scan shows a heterogeneous exophytic mass (white arrows) arising from the distal small bowel. Note the small fistula (black arrow) to the originating small bowel lumen.
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Figure 6. Small bowel GIST in a 50-year-old man. The mass was found incidentally during a work-up for prostate carcinoma and diagnosed with CT-guided biopsy. Contrast-enhanced CT scan shows a large, necrotic, exophytic mass (white arrowhead) arising from the ileum with a slightly enhancing solid component at the periphery. Note the multiple tumor vessels (black arrowheads) within the mass.
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Figure 7a. Small rectal GIST in an asymptomatic 66-year-old woman. The mass was found during an annual checkup and diagnosed with endoscopic biopsy. Axial T2-weighted (a) and contrast-enhanced T1-weighted (b) MR images obtained for a preoperative work-up show a small, enhancing, submucosal mass (arrow).
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Figure 7b. Small rectal GIST in an asymptomatic 66-year-old woman. The mass was found during an annual checkup and diagnosed with endoscopic biopsy. Axial T2-weighted (a) and contrast-enhanced T1-weighted (b) MR images obtained for a preoperative work-up show a small, enhancing, submucosal mass (arrow).
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Figure 8. Rectal GIST in a 39-year-old man with chronic back pain and worsening constipation. The diagnosis was made with endoscopic biopsy. Contrast-enhanced CT scan shows a slightly heterogeneous, massive perirectal mass (arrows), which is inseparable from the rectum with significant mass effect on the rectum. The mass was removed after imatinib treatment; it was found to have been located in the rectal wall.
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Figure 9. Esophageal GIST in a 40-year-old man with dysphagia. The diagnosis was made with endoscopic biopsy. Contrast-enhanced CT scan shows a large, exophytic, moderately enhancing mass (arrow) arising from the distal esophagus (E). This appearance is typical of primary GIST. The tumor recurred 18 months after esophagectomy.
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Figure 10. Extraintestinal GIST in a 36-year-old woman with a recent history of rectal prolapse. The diagnosis was made with surgical exploration. Contrast-enhanced CT scan shows a large, heterogeneous, moderately enhancing mass (arrows) at the rectovaginal septum; it is inseparable from both the vagina and the rectum. The mass replaced the rectovaginal connective tissue and was unresectable during the initial surgical exploration, but it was removed after treatment with imatinib. There has been no recurrence 22 months after surgery. The patient is currently undergoing surveillance.
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Figure 11. Advanced jejunal GIST with multiple hepatic metastases in a 56-year-old man. Contrast-enhanced CT scan shows multiple small hepatic metastases with solid (black arrows) or rim (white arrows) enhancement. (Reprinted, with permission, from reference 14.)
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Figure 12. Advanced GIST with multiple peritoneal and soft-tissue metastases in a 64-year-old woman with recurrent small bowel GIST. Contrast-enhanced CT scan shows multiple heterogeneous, enhancing peritoneal masses (arrows) and an anterior subcutaneous mass (arrowhead).
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Figure 13. Advanced GIST with multiple hepatic and peritoneal metastases in a 68-year-old man with recurrent gastric GIST. Contrast-enhanced CT scan shows multiple bulky, heterogeneous masses (arrows) in the liver and peritoneum. Note the multiple small tumor vessels (arrowheads) in the tumors.
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Figure 14a. Advanced GIST with pleural and bilateral pulmonary metastases in a 46-year-old man with recurrent esophageal GIST. Contrast-enhanced CT scans show irregular soft-tissue masses along the left diaphragmatic pleura (straight arrows in a, arrows in b) and bilateral lung nodules (arrowheads in b). A postoperative change from an esophagectomy is also evident (curved arrow in a).
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Figure 14b. Advanced GIST with pleural and bilateral pulmonary metastases in a 46-year-old man with recurrent esophageal GIST. Contrast-enhanced CT scans show irregular soft-tissue masses along the left diaphragmatic pleura (straight arrows in a, arrows in b) and bilateral lung nodules (arrowheads in b). A postoperative change from an esophagectomy is also evident (curved arrow in a).
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Figure 15a. Good response to imatinib in a 79-year-old woman with recurrent small bowel GIST with peritoneal implants. (a) Pretreatment contrast-enhanced CT scan shows a heterogeneous mesenteric mass with slight peripheral enhancement (arrows) abutting the liver. Note the tumor vessels (arrowhead) within the mass. (b, c) Follow-up CT scans show that the mass (large arrows) has become homogeneous and hypoattenuating, with significant decreases in the attenuation and size of the tumor 2 months after treatment (b) and further decreases 4 months after treatment (c). The tumor vessels are no longer evident. Such findings typify a good response to imatinib. A homogeneous hypoattenuating lesion in the liver (small arrow in c) is compatible with a treated hepatic metastasis.
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Figure 15b. Good response to imatinib in a 79-year-old woman with recurrent small bowel GIST with peritoneal implants. (a) Pretreatment contrast-enhanced CT scan shows a heterogeneous mesenteric mass with slight peripheral enhancement (arrows) abutting the liver. Note the tumor vessels (arrowhead) within the mass. (b, c) Follow-up CT scans show that the mass (large arrows) has become homogeneous and hypoattenuating, with significant decreases in the attenuation and size of the tumor 2 months after treatment (b) and further decreases 4 months after treatment (c). The tumor vessels are no longer evident. Such findings typify a good response to imatinib. A homogeneous hypoattenuating lesion in the liver (small arrow in c) is compatible with a treated hepatic metastasis.
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Figure 15c. Good response to imatinib in a 79-year-old woman with recurrent small bowel GIST with peritoneal implants. (a) Pretreatment contrast-enhanced CT scan shows a heterogeneous mesenteric mass with slight peripheral enhancement (arrows) abutting the liver. Note the tumor vessels (arrowhead) within the mass. (b, c) Follow-up CT scans show that the mass (large arrows) has become homogeneous and hypoattenuating, with significant decreases in the attenuation and size of the tumor 2 months after treatment (b) and further decreases 4 months after treatment (c). The tumor vessels are no longer evident. Such findings typify a good response to imatinib. A homogeneous hypoattenuating lesion in the liver (small arrow in c) is compatible with a treated hepatic metastasis.
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Figure 16a. Good response with a decrease in tumor attenuation after imatinib treatment in a 76-year-old man with recurrent gastric GIST with hepatic metastases. (a) Pretreatment contrast-enhanced CT scan shows multiple hypoattenuating hepatic metastases with slightly enhancing rims (arrows) in both lobes. (b) Contrast-enhanced CT scan obtained 2 months after treatment shows that the masses (arrows) have become homogeneous with a decrease in attenuation but have not substantially decreased in size.
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Figure 16b. Good response with a decrease in tumor attenuation after imatinib treatment in a 76-year-old man with recurrent gastric GIST with hepatic metastases. (a) Pretreatment contrast-enhanced CT scan shows multiple hypoattenuating hepatic metastases with slightly enhancing rims (arrows) in both lobes. (b) Contrast-enhanced CT scan obtained 2 months after treatment shows that the masses (arrows) have become homogeneous with a decrease in attenuation but have not substantially decreased in size.
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Figure 17a. Good response to imatinib treatment in a 71-year-old man with primary gastric GIST. (a) Contrast-enhanced CT scan shows a large, slightly heterogeneous mass (arrows) completely encasing or arising from the stomach. (b) Follow-up contrast-enhanced CT scan obtained 2 months after treatment shows that the mass (arrows) has become homogeneous with a significant decrease in attenuation, an appearance that typifies a good response to imatinib. (Reprinted, with permission, from reference 1.)
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Figure 17b. Good response to imatinib treatment in a 71-year-old man with primary gastric GIST. (a) Contrast-enhanced CT scan shows a large, slightly heterogeneous mass (arrows) completely encasing or arising from the stomach. (b) Follow-up contrast-enhanced CT scan obtained 2 months after treatment shows that the mass (arrows) has become homogeneous with a significant decrease in attenuation, an appearance that typifies a good response to imatinib. (Reprinted, with permission, from reference 1.)
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Figure 18a. Good response to imatinib treatment with increasing tumor size in a 51-year-old man with recurrent colon GIST with a peritoneal metastasis. (a) Pretreatment contrast-enhanced CT scan shows a peritoneal mass (arrow) with relatively low attenuation (42 HU). (b) Corresponding FDG PET scan shows markedly increased glucose uptake by the lesion (arrow). (c) Contrast-enhanced CT scan obtained 2 months after treatment shows that the mass (arrow) has become larger. However, the attenuation of the tumor has decreased (30 HU). (d) Corresponding FDG PET scan shows no appreciable glucose uptake by the lesion (arrow). The findings in c and d correlated with clinical improvement. Lack of a substantial decrease in tumor size during the early posttreatment period does not preclude a response to treatment. (Reprinted, with permission, from reference 14.)
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Figure 18b. Good response to imatinib treatment with increasing tumor size in a 51-year-old man with recurrent colon GIST with a peritoneal metastasis. (a) Pretreatment contrast-enhanced CT scan shows a peritoneal mass (arrow) with relatively low attenuation (42 HU). (b) Corresponding FDG PET scan shows markedly increased glucose uptake by the lesion (arrow). (c) Contrast-enhanced CT scan obtained 2 months after treatment shows that the mass (arrow) has become larger. However, the attenuation of the tumor has decreased (30 HU). (d) Corresponding FDG PET scan shows no appreciable glucose uptake by the lesion (arrow). The findings in c and d correlated with clinical improvement. Lack of a substantial decrease in tumor size during the early posttreatment period does not preclude a response to treatment. (Reprinted, with permission, from reference 14.)
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Figure 18c. Good response to imatinib treatment with increasing tumor size in a 51-year-old man with recurrent colon GIST with a peritoneal metastasis. (a) Pretreatment contrast-enhanced CT scan shows a peritoneal mass (arrow) with relatively low attenuation (42 HU). (b) Corresponding FDG PET scan shows markedly increased glucose uptake by the lesion (arrow). (c) Contrast-enhanced CT scan obtained 2 months after treatment shows that the mass (arrow) has become larger. However, the attenuation of the tumor has decreased (30 HU). (d) Corresponding FDG PET scan shows no appreciable glucose uptake by the lesion (arrow). The findings in c and d correlated with clinical improvement. Lack of a substantial decrease in tumor size during the early posttreatment period does not preclude a response to treatment. (Reprinted, with permission, from reference 14.)
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Figure 18d. Good response to imatinib treatment with increasing tumor size in a 51-year-old man with recurrent colon GIST with a peritoneal metastasis. (a) Pretreatment contrast-enhanced CT scan shows a peritoneal mass (arrow) with relatively low attenuation (42 HU). (b) Corresponding FDG PET scan shows markedly increased glucose uptake by the lesion (arrow). (c) Contrast-enhanced CT scan obtained 2 months after treatment shows that the mass (arrow) has become larger. However, the attenuation of the tumor has decreased (30 HU). (d) Corresponding FDG PET scan shows no appreciable glucose uptake by the lesion (arrow). The findings in c and d correlated with clinical improvement. Lack of a substantial decrease in tumor size during the early posttreatment period does not preclude a response to treatment. (Reprinted, with permission, from reference 14.)
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Figure 19a. Good response to imatinib treatment with increasing tumor size in a 41-year-old man with recurrent small bowel GIST with hepatic metastases. (a) Pretreatment contrast-enhanced CT scan shows multiple small, slightly hypoattenuating hepatic metastases (arrows). (b) Contrast-enhanced CT scan obtained 2 months after treatment shows that the lesions (arrows) have become homogeneous with decreased attenuation. However, the size of the tumors has increased. (c) Contrast-enhanced CT scan obtained 4 months after treatment shows that the lesion in the medial segment of the left lobe (long arrow) has significantly decreased in size. Note that the lesion in the right lobe (short arrow) has continued to increase in size but remains hypoattenuating. This lesion eventually became smaller on follow-up CT scans. (Reprinted, with permission, from reference 1.)
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Figure 19b. Good response to imatinib treatment with increasing tumor size in a 41-year-old man with recurrent small bowel GIST with hepatic metastases. (a) Pretreatment contrast-enhanced CT scan shows multiple small, slightly hypoattenuating hepatic metastases (arrows). (b) Contrast-enhanced CT scan obtained 2 months after treatment shows that the lesions (arrows) have become homogeneous with decreased attenuation. However, the size of the tumors has increased. (c) Contrast-enhanced CT scan obtained 4 months after treatment shows that the lesion in the medial segment of the left lobe (long arrow) has significantly decreased in size. Note that the lesion in the right lobe (short arrow) has continued to increase in size but remains hypoattenuating. This lesion eventually became smaller on follow-up CT scans. (Reprinted, with permission, from reference 1.)
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Figure 19c. Good response to imatinib treatment with increasing tumor size in a 41-year-old man with recurrent small bowel GIST with hepatic metastases. (a) Pretreatment contrast-enhanced CT scan shows multiple small, slightly hypoattenuating hepatic metastases (arrows). (b) Contrast-enhanced CT scan obtained 2 months after treatment shows that the lesions (arrows) have become homogeneous with decreased attenuation. However, the size of the tumors has increased. (c) Contrast-enhanced CT scan obtained 4 months after treatment shows that the lesion in the medial segment of the left lobe (long arrow) has significantly decreased in size. Note that the lesion in the right lobe (short arrow) has continued to increase in size but remains hypoattenuating. This lesion eventually became smaller on follow-up CT scans. (Reprinted, with permission, from reference 1.)
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Figure 20a. Recurrent small bowel GIST with a new peritoneal lesion at the site of previous disease in a 66-year-old woman. (a) Pretreatment contrast-enhanced CT scan shows multiple solid tumor implants (arrows) in the peritoneum and anterior abdominal wall. (b) On a contrast-enhanced CT scan obtained 14 months after treatment, the implants are no longer evident. (c) Contrast-enhanced CT scan obtained at 18-month follow-up shows a small recurrent lesion (arrow) at the site of previous disease. The lesion increased in size at 21-month follow-up.
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Figure 20b. Recurrent small bowel GIST with a new peritoneal lesion at the site of previous disease in a 66-year-old woman. (a) Pretreatment contrast-enhanced CT scan shows multiple solid tumor implants (arrows) in the peritoneum and anterior abdominal wall. (b) On a contrast-enhanced CT scan obtained 14 months after treatment, the implants are no longer evident. (c) Contrast-enhanced CT scan obtained at 18-month follow-up shows a small recurrent lesion (arrow) at the site of previous disease. The lesion increased in size at 21-month follow-up.
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Figure 20c. Recurrent small bowel GIST with a new peritoneal lesion at the site of previous disease in a 66-year-old woman. (a) Pretreatment contrast-enhanced CT scan shows multiple solid tumor implants (arrows) in the peritoneum and anterior abdominal wall. (b) On a contrast-enhanced CT scan obtained 14 months after treatment, the implants are no longer evident. (c) Contrast-enhanced CT scan obtained at 18-month follow-up shows a small recurrent lesion (arrow) at the site of previous disease. The lesion increased in size at 21-month follow-up.
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Figure 21a. Recurrence with new intratumoral nodules in a 59-year-old woman with recurrent gastric GIST in the omentum. (a) Pretreatment contrast-enhanced CT scan shows a large heterogeneous omental mass (arrows) with slight enhancement abutting the anterior surface of the stomach. (b, c) CT scans obtained 2 months (b) and 7 months (c) after treatment show that the mass (arrows) has become homogeneous with a decrease in attenuation and has progressively decreased in size. These findings indicate a good response to ima-tinib treatment. (d) Contrast-enhanced CT scan obtained 11 months after treatment shows two small nodules (arrows) within the mass. At surgery, the nodules were confirmed to be viable tumor tissue.
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Figure 21b. Recurrence with new intratumoral nodules in a 59-year-old woman with recurrent gastric GIST in the omentum. (a) Pretreatment contrast-enhanced CT scan shows a large heterogeneous omental mass (arrows) with slight enhancement abutting the anterior surface of the stomach. (b, c) CT scans obtained 2 months (b) and 7 months (c) after treatment show that the mass (arrows) has become homogeneous with a decrease in attenuation and has progressively decreased in size. These findings indicate a good response to ima-tinib treatment. (d) Contrast-enhanced CT scan obtained 11 months after treatment shows two small nodules (arrows) within the mass. At surgery, the nodules were confirmed to be viable tumor tissue.
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Figure 21c. Recurrence with new intratumoral nodules in a 59-year-old woman with recurrent gastric GIST in the omentum. (a) Pretreatment contrast-enhanced CT scan shows a large heterogeneous omental mass (arrows) with slight enhancement abutting the anterior surface of the stomach. (b, c) CT scans obtained 2 months (b) and 7 months (c) after treatment show that the mass (arrows) has become homogeneous with a decrease in attenuation and has progressively decreased in size. These findings indicate a good response to ima-tinib treatment. (d) Contrast-enhanced CT scan obtained 11 months after treatment shows two small nodules (arrows) within the mass. At surgery, the nodules were confirmed to be viable tumor tissue.
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Figure 21d. Recurrence with new intratumoral nodules in a 59-year-old woman with recurrent gastric GIST in the omentum. (a) Pretreatment contrast-enhanced CT scan shows a large heterogeneous omental mass (arrows) with slight enhancement abutting the anterior surface of the stomach. (b, c) CT scans obtained 2 months (b) and 7 months (c) after treatment show that the mass (arrows) has become homogeneous with a decrease in attenuation and has progressively decreased in size. These findings indicate a good response to ima-tinib treatment. (d) Contrast-enhanced CT scan obtained 11 months after treatment shows two small nodules (arrows) within the mass. At surgery, the nodules were confirmed to be viable tumor tissue.
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Figure 22a. Recurrence with a new intratumoral nodule in a 72-year-old man with duodenal GIST metastatic to the liver. (a) Contrast-enhanced CT scan obtained 12 months after treatment shows a tiny nodule (arrow) within a hypoattenuating metastasis in the right lobe of the liver. (b, c) Follow-up contrast-enhanced CT scans obtained 17 months (b) and 22 months (c) after treatment show that the enhancing nodule (arrow in b, arrowhead in c) has progressively increased in size. At 22-month follow-up, the nodule completely fills the mass (arrow in c). The mass eventually became enlarged as well. (Reprinted, with permission, from reference 1.)
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Figure 22b. Recurrence with a new intratumoral nodule in a 72-year-old man with duodenal GIST metastatic to the liver. (a) Contrast-enhanced CT scan obtained 12 months after treatment shows a tiny nodule (arrow) within a hypoattenuating metastasis in the right lobe of the liver. (b, c) Follow-up contrast-enhanced CT scans obtained 17 months (b) and 22 months (c) after treatment show that the enhancing nodule (arrow in b, arrowhead in c) has progressively increased in size. At 22-month follow-up, the nodule completely fills the mass (arrow in c). The mass eventually became enlarged as well. (Reprinted, with permission, from reference 1.)
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Figure 22c. Recurrence with a new intratumoral nodule in a 72-year-old man with duodenal GIST metastatic to the liver. (a) Contrast-enhanced CT scan obtained 12 months after treatment shows a tiny nodule (arrow) within a hypoattenuating metastasis in the right lobe of the liver. (b, c) Follow-up contrast-enhanced CT scans obtained 17 months (b) and 22 months (c) after treatment show that the enhancing nodule (arrow in b, arrowhead in c) has progressively increased in size. At 22-month follow-up, the nodule completely fills the mass (arrow in c). The mass eventually became enlarged as well. (Reprinted, with permission, from reference 1.)
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Figure 23a. Development of fluid retention as an adverse effect of imatinib in a 64-year-old woman with metastatic small bowel GIST. (a) Pretreatment contrast-enhanced CT scan shows multiple heterogeneous and enhancing masses in the peritoneum (black arrow) and anterior subcutaneous tissue (white arrow). (b) On a follow-up contrast-enhanced CT scan obtained 2 months after treatment, the masses (arrows) have become smaller. Note the new ascites (*). New ascites should not be misinterpreted as an indicator of new peritoneal disease when the disease is otherwise improving.
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Figure 23b. Development of fluid retention as an adverse effect of imatinib in a 64-year-old woman with metastatic small bowel GIST. (a) Pretreatment contrast-enhanced CT scan shows multiple heterogeneous and enhancing masses in the peritoneum (black arrow) and anterior subcutaneous tissue (white arrow). (b) On a follow-up contrast-enhanced CT scan obtained 2 months after treatment, the masses (arrows) have become smaller. Note the new ascites (*). New ascites should not be misinterpreted as an indicator of new peritoneal disease when the disease is otherwise improving.
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Figure 24a. Development of an intratumoral hemorrhage as an adverse effect of imatinib in a 60-year-old woman with recurrent small bowel GIST in the liver. (a) Pretreatment contrast-enhanced CT scan shows multiple heterogeneous hepatic metastases with moderately enhancing solid nodules at the peripheries (arrows). Prominent tumor vessels (arrowheads) are noted within the masses. (b) Contrast-enhanced CT scan obtained 2 months after imatinib treatment shows that the tumors (arrows) have become homogeneous and the enhancing tumor nodules have markedly resolved, indicating a good response to the treatment. (c) Unenhanced CT scan from the same data acquisition shows a fluid-fluid level within the smaller tumor (black arrow); the fluid-fluid level was caused by an intratumoral hemorrhage. The attenuation of the smaller tumor increased from 73 HU to 115 HU. White arrow = larger tumor.
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Figure 24b. Development of an intratumoral hemorrhage as an adverse effect of imatinib in a 60-year-old woman with recurrent small bowel GIST in the liver. (a) Pretreatment contrast-enhanced CT scan shows multiple heterogeneous hepatic metastases with moderately enhancing solid nodules at the peripheries (arrows). Prominent tumor vessels (arrowheads) are noted within the masses. (b) Contrast-enhanced CT scan obtained 2 months after imatinib treatment shows that the tumors (arrows) have become homogeneous and the enhancing tumor nodules have markedly resolved, indicating a good response to the treatment. (c) Unenhanced CT scan from the same data acquisition shows a fluid-fluid level within the smaller tumor (black arrow); the fluid-fluid level was caused by an intratumoral hemorrhage. The attenuation of the smaller tumor increased from 73 HU to 115 HU. White arrow = larger tumor.
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Figure 24c. Development of an intratumoral hemorrhage as an adverse effect of imatinib in a 60-year-old woman with recurrent small bowel GIST in the liver. (a) Pretreatment contrast-enhanced CT scan shows multiple heterogeneous hepatic metastases with moderately enhancing solid nodules at the peripheries (arrows). Prominent tumor vessels (arrowheads) are noted within the masses. (b) Contrast-enhanced CT scan obtained 2 months after imatinib treatment shows that the tumors (arrows) have become homogeneous and the enhancing tumor nodules have markedly resolved, indicating a good response to the treatment. (c) Unenhanced CT scan from the same data acquisition shows a fluid-fluid level within the smaller tumor (black arrow); the fluid-fluid level was caused by an intratumoral hemorrhage. The attenuation of the smaller tumor increased from 73 HU to 115 HU. White arrow = larger tumor.
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Figure 25a. Spurious new hepatic lesion in a 59-year-old woman with gastric GIST metastatic to the liver. (a–c) Unenhanced (a), early arterial phase (b), and late arterial phase (c) pretreatment CT scans show an enhancing mass (arrow) in the left lobe of the liver. (d) On a portal venous phase CT scan, the mass (arrow) is invisible. (e) Portal venous phase CT scan obtained 2 months after treatment clearly shows the mass (arrow) owing to its decreased enhancement, which indicates a good response to the treatment. (Reprinted, with permission, from reference 1.)
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Figure 25b. Spurious new hepatic lesion in a 59-year-old woman with gastric GIST metastatic to the liver. (a–c) Unenhanced (a), early arterial phase (b), and late arterial phase (c) pretreatment CT scans show an enhancing mass (arrow) in the left lobe of the liver. (d) On a portal venous phase CT scan, the mass (arrow) is invisible. (e) Portal venous phase CT scan obtained 2 months after treatment clearly shows the mass (arrow) owing to its decreased enhancement, which indicates a good response to the treatment. (Reprinted, with permission, from reference 1.)
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Figure 25c. Spurious new hepatic lesion in a 59-year-old woman with gastric GIST metastatic to the liver. (a–c) Unenhanced (a), early arterial phase (b), and late arterial phase (c) pretreatment CT scans show an enhancing mass (arrow) in the left lobe of the liver. (d) On a portal venous phase CT scan, the mass (arrow) is invisible. (e) Portal venous phase CT scan obtained 2 months after treatment clearly shows the mass (arrow) owing to its decreased enhancement, which indicates a good response to the treatment. (Reprinted, with permission, from reference 1.)
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Figure 25d. Spurious new hepatic lesion in a 59-year-old woman with gastric GIST metastatic to the liver. (a–c) Unenhanced (a), early arterial phase (b), and late arterial phase (c) pretreatment CT scans show an enhancing mass (arrow) in the left lobe of the liver. (d) On a portal venous phase CT scan, the mass (arrow) is invisible. (e) Portal venous phase CT scan obtained 2 months after treatment clearly shows the mass (arrow) owing to its decreased enhancement, which indicates a good response to the treatment. (Reprinted, with permission, from reference 1.)
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Figure 25e. Spurious new hepatic lesion in a 59-year-old woman with gastric GIST metastatic to the liver. (a–c) Unenhanced (a), early arterial phase (b), and late arterial phase (c) pretreatment CT scans show an enhancing mass (arrow) in the left lobe of the liver. (d) On a portal venous phase CT scan, the mass (arrow) is invisible. (e) Portal venous phase CT scan obtained 2 months after treatment clearly shows the mass (arrow) owing to its decreased enhancement, which indicates a good response to the treatment. (Reprinted, with permission, from reference 1.)
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Copyright © 2006 by the Radiological Society of North America.
