Imaging

Gastrinoma

Preliminary Diagnosis: Gastrinoma

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 gastrinoma.

Advantages

  • Has good spatial resolution and allows for localization and enhancement characterization of pancreatic endocrine tumors

  • Has high sensitivity but may require complementary imaging

  • Can identify hepatic and other metastatic lesions

  • Can identify non-hyperfunctioning pancreatic endocrine tumors

Disadvantages

  • Ionizing radiation

  • May require additional complementary imaging

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 gastrinoma.

MR with and without contrast

Advantages

  • Lack of ionizing radiation

  • Has comparable sensitivity and ability to identify metastases as CT

Disadvantages

  • Requires a longer scan time

  • Requires a higher level of patient compliance and can be more prone to artifact

Angiography

Advantages

  • Hepatic vein sampling and pancreatic arterial stimulation allows for evaluation of functional status and can be diagnostic.

Disadvantages

  • Ionizing radiation

  • Limited to patients who can tolerate intravenous contrast

Nuclear imaging

Advantages

  • Several options exist including octreotide-based radionuclides, PET/CT, as well as newer agents targeted against a wider range of somatostatin receptors.

  • Clinical utility may vary depending on the type of endocrine neoplasm. For instance, gastrinomas may have a greater imaging sensitivity than insulinoma due to relatively higher expression of somatostatin receptors.

Disadvantages

  • Ionizing radiation

  • Nuclear imaging 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 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.

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