Gastrointestinal stromal tumor CT
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Parminder Dhingra, M.D. [2]
Gastrointestinal stromal tumor Microchapters |
Differentiating Gastrointestinal stromal tumor from other Diseases |
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Overview
Abdominal CT scan may be helpful in the diagnosis of gastrointestinal stromal tumor.
CT scan
Appearance of GIST on a CT scan vary with size and location. Typically the mass is of soft tissue density with central areas of lower density when necrosis is present (usually in larger tumours). Enhancement is typically peripheral (due to central necrosis). Calcification is uncommon (3%). Metastases (distant, peritoneal, omental) or direct invasion into adjacent organs may be seen in more aggressive lesions. Lymph node enlargement is not a feature.[1]
- A CT scan of the abdomen and pelvis is the imaging test of choice and an important tool in the diagnosis of GIST.
- CT scan can be used to determine the size, location and staging of the GIST.
- A CT can accurately de-mark surrounding structures, multiple tumors and metastases.
- The size of GIST determined by a CT scan can also be ised to classify the severity of GIST.
- Small GIST (< 5 cm) are homogeneous with clear boundaries and intraluminal pattern of growth.
- Intermediate GIST (size of 5-10 cm) are heterogeneous with irregular borders and intra or extra-luminal pattern of growth.
- Large GISTs (>10 cm) are heterogeneous with irregular borders and local or distant spread.
Sharply demarcated Homogeneous density Mainly exhibit intraluminal growth patterns
Computed tomography (CT) is the imaging test of choice for diagnosing GIST. On a CT scan, a malignant GIST with metastasis may have the following findings
- size greater than 10 cm
- calcifications
- irregular margins
- heterogeneous, lobulated
- lymphadenopathy
- ulceration
- extraluminal and mesenteric fat infiltration
CT with contrast (oral) is superior to normal CT. CT with contrast can better visualize the
- thickness of the small bowel
- deep ileal loops without superimposition
- evaluation of surrounding mesentery
MRI is more accurate than CT for delineating rectal GISTs and in detecting liver metastasis, hemorrhage and necrosis.