Figure 8b. Small-bowel carcinoid tumor. (a) Image from an enteroclysis study performed in a patient with a midgut carcinoid tumor demonstrates mucosal thickening (arrow), angulation, and fixation of a segment of the distal part of the ileum because of the tumor and associated mesenteric fibrosis. (b) Axial CT image in another patient with a distal ileal carcinoid tumor shows an area of desmoplastic reaction in the small-bowel mesentery (arrow). (c) Coronal T2-weighted MR image shows a large mesenteric mass with characteristic surrounding mesenteric fibrosis and with thickening of the ileal wall because of ischemia (arrows).