Neuroendocrine tumors of the small bowel: evaluation with MR-enterography.

Purpose: To determine the sensitivity of magnetic resonance (MR)-enterography for the detection of neuroendocrine tumors of the small-bowel (NETSB) and analyze the imaging presentation of NETSB on MR-enterography.

Patients & Methods: The MR-enterography studies (including HASTE, TruFISP, and 3D VIBE MR sequences before and after intravenous administration of a gadolinium-chelate) of 19 patients with pathologically confirmed NETSB were blindly reviewed. Images were analyzed with respect to imaging presentation. Sensitivity of MR-enterography as well as that of each individual MR-enterography sequence for the diagnosis of NETSB was estimated with 95% confidence intervals (CIs). Comparisons between individual MR-enterography sequences were performed using the McNemar test.

Results: Twenty-seven NETSBs were confirmed in 19 patients. Overall sensitivity of MR-enterography for NETSB detection was 74% (20/27; 95% CI: 54-89%) on a per-lesion basis. On a per-patient basis, MR-enterography had a sensitivity of 95% (18/19; 95% CI: 74-100%) for the detection of NETSB. Best degrees of sensitivity were achieved with 3D VIBE MR-enterography sequences after intravenous administration of a gadolinium-chelate (Se=95%; 18/19) by comparison with HASTE (Se=26%; 5/19) and TruFISP (Se=26%; 5/19) sequences (P=.00022). Visible focal small-bowel mass, mesenteric stranding, and mesenteric mass were found in 16/19 (84%), 17/19 (89%), and 15/19 (79%) patients, respectively.

Conclusion: MR-enterography shows highly suggestive features for the diagnosis of NETSB and has high degrees of sensitivity for the diagnosis of NETSB on a per-patient basis.