The gastrocolic trunk and its tributaries: CT evaluation.

Dilatation or occlusion of the gastrocolic trunk (GT) may be a clue to a portal venous or pancreatic pathologic condition. To evaluate the normal and abnormal appearances of the GT and its tributaries at computed tomography (CT), the CT scans, angiograms, and surgical-pathologic records of 21 patients with cancer of the pancreas and 15 patients with chronic pancreatitis were reviewed retrospectively. The CT examinations of 30 patients with metastatic disease of the liver and no known pancreatic disease were studied for comparison. A normal GT (2.6-4.7-mm diameter) was identifiable in 48% of the control group in CT scans obtained with 10-mm-thick sections and in 90% of CT scans obtained with 5-mm-thick sections. The GT was dilated in five patients with isolated splenic vein occlusion and in five patients with occlusion or stenosis of the portal-superior mesenteric vein confluence (P-SMVC) above the level of the GT entry into the superior mesenteric vein. The GT was obliterated in eight patients and was associated with P-SMVC occlusion. Findings at surgery confirmed tumor extension into the root of the transverse mesocolon in three patients with cancer of the pancreas. Abnormal findings at CT, however, do not enable differentiation between benign and malignant pancreatic diseases.