Imaging

Paraganglioma

Preliminary Diagnosis: Paraganglioma

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

  • MR with and without contrast

  • However, if the primary site is unknown but clinically suspected, CT abdomen with contrast or nuclear imaging would be useful for initial localization

  • Thin-cut noncontrast temporal bone CT is first-line for glomus jugulare tumors

  • Contrast temporal bone CT can be the initial evaluation of glomus tympanicum tumors

II. Describe the advantages and disadvantages of this technique for diagnosis of paraganglioma.

Advantages

  • Superior contrast resolution

  • Allows for localization and enhancement characterization of a paraganglioma

  • No ionizing radiation burden

  • Comparable to CT for pheochromocytoma and other abdominal and thoracic paragangliomas

Disadvantages

  • MR has relatively limited evaluation of small paragangliomas that are located near the temporal bone (jugulare, tympanicum)

  • Expensive

  • Time consuming

  • Requires significant patient cooperation to minimize motion artifact

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

  • Poor renal function

  • MR-incompatible hardware

IV. What alternative imaging techniques are available?

  • CT with contrast

  • Angiography

  • Nuclear imaging

V. Describe the advantages and disadvantages of the alternative techniques for diagnosis of paraganglioma.

CT with contrast

Advantages

  • Better spatial resolution, specifically for paragangliomas near the temporal bone, than MR

  • Faster scan time with better patient compliance than MR

Disadvantages

  • Exposure to ionizing radiation

Angiography

Advantages

  • Identifies feeding arteries and collateralization

  • Allows for preoperative embolization

Disadvantages

  • Exposure to ionizing radiation

  • Invasive procedure

Nuclear Imaging

Advantages

  • Octreotide- or MIBG-based agents can evaluate functional status

Disadvantages

  • Greater specificity than sensitivity

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

CT with contrast

  • Poor renal function

  • Known contrast allergy

  • Pregnancy

Angiography

  • Poor renal function

  • Known contrast allergy

  • Pregnancy

  • Hypocoagulable state (platelets <50k, INR>2.0)

Nuclear Imaging

  • Pregnancy

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