Preliminary Diagnosis: Thyroid Adenoma

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

  • Ultrasound of the thyroid gland.

II. Describe the advantages and disadvantages of this technique for diagnosing thyroid adenoma.

Advantages
  • Does not expose patients to ionizing radiation.

  • Highly portable and relatively inexpensive imaging modality.


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  • Helps detail the vascularity and complexity of any suspected thyroid abnormalities.

  • Helps guide percutaneous biopsy and fine needle aspiration.

Disadvantages
  • Highly operator dependent.

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

No specific contraindications to ultrasound exist.

IV. What alternative imaging techniques are available?

  • CT imaging with IV contrast.

  • MR of the thyroid bed.

  • Nuclear medicine thyroid scintigraphy utilizing Technetium 99m pertechtenate and I-123.

V. Describe the advantages and disadvantages of the alternative techniques for diagnosing thyroid adenoma.

CT imaging with IV contrast
Advantages
  • Offers better evaluation of the surrounding soft tissues and osseous structures than other imaging modalities.

  • Better evaluates for extension of local thyroid disease/neoplasm and distant metastasis.

Disadvantages
  • Less sensitive and specific in characterizing the complexity and vascularity of thyroid nodular lesions.

  • Less portable and relatively more expensive compared to sonographic imaging.

  • Exposes patients to ionizing radiation.

MR of the thyroid bed
Advantages
  • Does not expose patients to ionizing radiation.

  • Offers exquisite evaluation of the surrounding soft tissues.

  • Highly adept in detailing any evidence of distant cervical lymphadenopathy and metastasis.

Disadvantages
  • Less adept in detailing subtle thyroid mineralization, which is characteristic in certain thyroid abnormalities, i.e., medullary carcinoma.

  • Less adept in guiding percutaneous biopsy and therapy.

  • May be subject to motion and susceptibility weighted artifact, degrading image quality.

  • Expensive.

  • Time consuming.

Nuclear medicine thyroid scintigraphy utilizing Technetium 99m pertechtenate and I-123
Advantages
  • Moderate in sensitivity and moderate in detailing hot or cold thyroid nodules.

Disadvantages
  • Limited in detailing the surrounding soft tissues, vasculature, and osseous structures.

  • Exposes patients to ionizing radiation.

  • Limited in sensitivity and specificity in detecting and detailing small thyroid nodules.

  • Unable to adequately detail the vascularity of a thyroid lesion.

  • Expensive.

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

CT imaging with IV contrast
  • May be contraindicated in pregnant patients.

  • IV contrast may be contraindicated in patients with renal failure or contrast allergy.

MR of the thyroid bed
  • Contraindicated in patients with non-MR compatible hardware.

Nuclear medicine thyroid scintigraphy utilizing Technetium 99m pertechtenate and I-123
  • May be contraindicated in pregnant and breast feeding patients.