Sarcoidosis

Preliminary Diagnosis: Sarcoidosis

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

Plain radiography.

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

Advantages

• Highly portable and quick imaging modality.

• Exposes patients to negligible ionizing radiation.

Disadvantages

• Poorly sensitive and limited specificity in evaluating for sarcoidosis.

• Does not help in treatment, therapy, or percutaneous intervention.

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

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

No specific contraindications to plain radiography exist. Some institutions may require consent for pregnant women.

IV. What alternative imaging techniques are available?

• CT imaging with IV contrast.

• MR imaging with IV contrast.

• Nuclear medicine scan, including Gallium 67 nuclear medicine imaging.

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

CT imaging with IV contrast

Advantages

• Highly sensitive and specific in evaluating for sarcoidosis.

• Offers better evaluation of the surrounding soft tissues, osseous structures, and vasculature than other imaging modalities.

• CT imaging with contrast may better evaluate the extension of disease.

• Helps guide percutaneous intervention, treatment, and therapy.

Disadvantages

• Exposes patients to larger amounts of ionizing radiation than plain radiography.

MR imaging with IV contrast

Advantages

• Offers exquisite visualization of the surrounding soft tissues.

• MR imaging with contrast offers exquisite visualization of the extension of soft tissue abnormality.

• Does not expose patients to ionizing radiation.

Disadvantages

• Limited in evaluating the surrounding osseous structures.

• Less adept in guiding percutaneous intervention, treatment, and therapy.

• Less adept in detailing subtle areas of mineralization to suggest granulomatous disease.

• Expensive.

• Time consuming.

• Requires significant patient cooperation to minimize motion artifact.

Nuclear medicine scan including Gallium 67 nuclear medicine imaging

Advantages

• Moderately sensitive and moderately specific in diagnosing and detecting sarcoidosis affecting the salivary glands and the intrathoracic lymph nodes (panda and lambda signs).

Disadvantages

• Offers limited detail of the surrounding soft tissues, osseous structures, and vasculature.

• Less adept in guiding percutaneous intervention, treatment, and therapy than other imaging modalities.

• Exposes patients to ionizing radiation.

• May be contraindicated in pregnant patients or those that are breastfeeding.

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

CT imaging with IV contrast

• May be contraindicated in pregnant patients.

• Relative contraindication of IV contrast in patients with renal failure or contrast allergy.

MR imaging with IV contrast

• Contraindicated in patients with non-MR compatible hardware.

Nuclear medicine scan including Gallium 67 nuclear medicine imaging

• May be contraindicated in patients who are pregnant or those that are breastfeeding.