Preliminary Diagnosis: Hypersensitivity Pneumonitis

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

  • Chest x-ray, PA and lateral view

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

Advantages
  • Fast and portable imaging modality

  • Exposes patients to minimal ionizing radiation

Disadvantages
  • Less sensitive and specific in diagnosing a primary pulmonary process or detecting a secondary complication

  • Offers less detail of the lung parenchyma and surrounding vascular, osseous, and soft tissue structures compared to companion cross-sectional imaging

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

  • No specific contraindications to plain radiography exist. Consent may be required for pregnant patients at some institutions.

IV. What alternative imaging techniques are available?

  • CT of the chest without contrast/high resolution CT of the chest without contrast

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

CT of the chest without contrast/high resolution CT of the chest without contrast
Advantages
  • Much more sensitive and specific in detecting a primary parenchymal or pleural process, or detecting any secondary complication than plain radiography

  • May help direct and guide treatment

  • CT/high resolution CT imaging offers exquisite detail of the secondary pulmonary lobule and surrounding interlobular and intralobular septa, which helps clinch a definite diagnosis

Disadvantages
  • Exposes patients to ionizing radiation

  • Less portable and more expensive compared to plain radiography

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

CT of the chest without contrast/high resolution CT of the chest without contrast
  • May be contraindicated in pregnant patients