Detection of small, functional islet cell tumors in the pancreas: selection of MR imaging sequences for optimal sensitivity

Radiology. 2000 Feb;214(2):483-90. doi: 10.1148/radiology.214.2.r00fe32483.


Purpose: To determine the sensitivity and specificity of magnetic resonance (MR) imaging for depicting pancreatic small, functional islet cell tumors and the minimum number of sequences for expedient diagnosis.

Materials and methods: Twenty-eight patients clinically suspected to have functional islet cell tumors underwent T1- and T2-weighted spin-echo (SE) MR imaging with and without fat suppression, T2-weighted fast SE imaging, and spoiled gradient-echo (GRE) imaging before and after injection of gadopentetate dimeglumine. Sensitivity, specificity, and the best and minimum number of sequences for definitive diagnosis were determined.

Results: MR images depicted proved islet cell tumors in 17 of 20 patients (sensitivity, 85%). Images were true-negative in eight patients with negative follow-up examination results for more than 1 year. Specificity was 100%; positive predictive value, 100%; and negative predictive value, 73%. Among 20 patients with tumor, T1-weighted SE images with fat suppression and nonenhanced spoiled GRE images each showed lesions in 15 (75%); T2-weighted conventional SE with fat suppression, in 13 (65%); gadolinium-enhanced spoiled GRE, in 12 (60%); and T2-weighted fast SE, in seven of 10 patients (70%).

Conclusion: MR imaging accurately depicts small islet cell tumors. T2-weighted fast SE and spoiled GRE sequences usually suffice. Gadolinium-enhanced sequences are needed only if MR imaging results are equivocal or negative.

MeSH terms

  • Adenoma, Islet Cell / diagnosis*
  • Adipose Tissue
  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Contrast Media
  • Diagnosis, Differential
  • Female
  • Follow-Up Studies
  • Gadolinium DTPA
  • Humans
  • Image Enhancement / methods
  • Image Processing, Computer-Assisted / methods*
  • Magnetic Resonance Imaging / methods*
  • Male
  • Middle Aged
  • Pancreatic Neoplasms / diagnosis*
  • Predictive Value of Tests
  • Prospective Studies
  • Sensitivity and Specificity


  • Contrast Media
  • Gadolinium DTPA