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

Figure 1 General use of maximum intensity projections, multiplanar reconstructions, volume rendered technique and surface shading. A, B: Coronal surface rendering technique with two different window settings allows to obtain a 3D understanding of a mesenteric mass (arrowhead) and its relationship to the SMV (arrow). The lower window setting (A) includes more soft tissue detail, and better depicts the mesenteric structures and adjacent bowel loops, while the higher window setting (B) excludes structures with lower attenuation and focuses the view on vascular morphology; C: Coronal venous phase VRT image showing the mesenteric mass with calcifications (arrowhead), and the relationship to the SMV (arrow), which can be visualized in its entire course to the portosplenic confluence (blue arrowhead); D: Volume rendering of arterial phase CTA data simultaneously depicts hypervascular liver metastases (arrows) and the relationship of the mesenteric mass to the SMA with vascular encasement and rarefaction of SMA branches (arrowhead); E: 3D surface shading has its major advantage in the depiction the vascular anatomy (SMA, arrow), while the chosen windowing reduces the conspicuity of the mesenteric mass (arrowhead) and removes the voxels pertaining to the liver metastases and the hepatic parenchyma for depiction of the hepatic arteries; F, G: Comparison of sagittal venous phase slice (F) and VRT postprocessed image (G). The mesenteric mass (arrowheads) and its relationship to the adjacent vessels is better defined with VRT (G); H, I: Comparison of coronal VRT (H) to coronal thick slab MPR (I). While VRT makes the spatial relationships more apparent, MPR better demonstrates vascular anatomical detail and the relationship of vessels to the mesenteric mass (arrowheads). Also, a small calcification in the mesenteric mass (arrow) is only visualized with MPR, while the VRT algorithm hides this important detail. VRT: Volume rendered technique; MPR: Multiplanar reconstructions; MIP: Maximum intensity projections; SMV: Superior mesenteric vein; CTA: Computed tomography angiography; SMA: Superior mesenteric artery; 3D: Three-dimensional.