Role of computed tomography angiography in detection and staging of small bowel carcinoid tumors

Figure 9 Metastatic small bowel carcinoid. A 66-year-old male with metastatic small bowel carcinoid. The tumor was found unresectable with large mesenteric nodal metastatic disease encasing SMA and SMV, and with liver metastases. In this case the primary tumor location is unknown (and possibly very small), in the presence of bulky regional metastatic disease and liver metastatic disease. It also demonstrates the evaluation of vascular complications (SMV occlusion, encasement of SMV and SMA) using 3D imaging. It is not unusual that the primary tumor is much smaller than the nodal metastatic disease. A: Arterial phase axial image demonstrates a large mesenteric mass with surrounding desmoplastic reaction (arrowheads), compatible with regional nodal metastatic disease from carcinoid tumor. The primary tumor was not identified on the exam; B: Arterial phase axial image demonstrates a hypervascular metastasis in segment IV B of the liver; C: Axial venous phase image shows extensive peripancreatic collateral vessels (arrowheads) as a result of SMV occlusion by tumor encasement; D: Encasement of the SMV (arrowhead) and SMA (blue arrowhead) by the tumor. The distal SMV is severely narrowed (arrowhead), while the more proximal SMV is completely occluded by the tumor (arrow); E: Coronal VRT arterial phase image demonstrates the large mesenteric mass (arrowheads), which encases the SMA and its branches; F: Coronal thick slab MIP arterial phase image demonstrates the calcified mesenteric mass (arrowheads), encasing SMA branches; G: Coronal VRT venous phase image shows multiple peripancreatic collateral vessels (blue arrowheads) to better advantage than axial or multiplanar imaging; H: Coronal thick slab venous phase MIP image shows moderately dilated mesenteric veins (arrowheads) resulting from SMV occlusion. VRT: Volume rendered technique; MIP: Maximum intensity projections; SMA: Superior mesenteric artery; SMV: Superior mesenteric vein.