Preliminary Diagnosis: Glucagonoma

I. What imaging technique is first-line for this diagnosis

  • CT of the abdomen and pelvis with IV contrast, pancreas protocol

II. Describe the advantages and disadvantages of this technique for glucagonoma.

Advantages
  • Has good spatial resolution and allows for localization and enhancement characterization of pancreatic endocrine tumors
  • Has high sensitivity
  • Can identify hepatic and other metastatic lesions
  • Can identify non-hyperfunctioning pancreatic endocrine tumors
Disadvantages
  • Requires ionizing radiation
  • May require additional complementary imaging studies

III. What are the contraindications for the first-line imaging technique?

  • Known allergy to intravenous contrast
  • Decreased renal function
  • Pregnancy

IV. What alternative imaging techniques are available?

  • MR with and without contrast
  • Angiography
  • Nuclear imaging: options and availability will vary by institution

V. Describe the advantages and disadvantages of the alternative techniques for glucagonoma.

MR with and without contrast
Advantages
  • Lack of ionizing radiation
  • Has comparable sensitivity and ability to identify metastases as CT
Disadvantages
  • Longer scan time
  • Requires a higher level of patient compliance and can be more prone to artifact
Angiography
Advantages
  • Allows for evaluation of functional status
  • Can be diagnostic
Disadvantages
  • Use of ionizing radiation
  • Limited to patients who can tolerate IV contrast
Nuclear imaging
Advantages
  • May be beneficial for localization and staging
Disadvantages
  • Clinical utility may vary, especially for small gastrinomas in the duodenum
  • Uses ionizing radiation
  • Options and availability will vary by institution; consultation is recommended to optimize the study.

VI. What are the contraindications for the alternative imaging techniques?

MR with and without contrast
  • Inability to cooperate for the exam
  • Presence of non-MR compatible metal
  • Poor renal function
Angiography
  • Poor renal function
  • Hypocoagulable state: elevated prothrombin time/international normalized ratio (PT/INR), low platelets
Nuclear imaging
  • Relative contraindication in pregnancy

References:

Lewis, RB, Lattin, GE, Paal, E. “Pancreatic endocrine tumors: radio-clinicopathologic correlation”. Radiographics. vol. 30. 2010. pp. 1445-1464.