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• What is it:
  • Peribronchovascular findings refer to:
    • Abnormalities located along the bronchovascular bundles,
    • which consist of bronchi, pulmonary arteries, and accompanying lymphatics.
  • These findings often reflect:
    • Airway-adjacent inflammation,
    • Lymphatic involvement,
    • Vascular abnormalities, or
    • Neoplastic processes.
• Etymology:
  • Derived from the Greek word peri- (around), bronchos (windpipe), and vasculum (vessel), referring to the structures surrounding the bronchi and blood vessels.
• AKA:
  • Peribronchovascular thickening, Bronchovascular bundle involvement.
• How does it appear on each relevant imaging modality:
  • Chest X-ray:
    • May show reticulonodular opacities or thickened bronchovascular bundles.
    • Findings are typically subtle and best seen in the central or hilar regions.
  • Chest CT:
    • Parts: Abnormalities along the bronchovascular bundles extending from the hilum to the periphery.
    • Size: Varies from micronodules to larger confluent abnormalities.
    • Shape: Linear or nodular thickening around bronchi and pulmonary vessels.
    • Position:
      • Predominantly central but may extend into the periphery along vascular and airway branches.
    • Character:
      • May present as:
        • Smooth thickening (e.g., pulmonary edema).
        • Nodular thickening (e.g., sarcoidosis or lymphangitic carcinomatosis).
    • Time:
      • Can be transient (e.g., resolving infections) or progressive (e.g., neoplasms or fibrosis).
  • PET-CT:
    • Useful for evaluating metabolic activity, particularly in cases of suspected malignancy or granulomatous disease.
    • Recommended for abnormalities larger than 7 mm or diffuse nodular patterns.
• These findings reflect:
  • Airway-adjacent pathology:
    • Inflammation:
      • Sarcoidosis (perilymphatic nodules).
      • Hypersensitivity pneumonitis.
    • Infection:
      • Tuberculosis (peribronchovascular granulomas).
      • Fungal infections (e.g., histoplasmosis).
    • Lymphatic involvement:
      • Lymphangitic carcinomatosis.
      • Perilymphatic metastases.
    • Neoplastic processes:
      • Lymphoma.
• Differential diagnosis:
  • Infection:
    • Tuberculosis (peribronchovascular granulomas).
    • Fungal infections (e.g., aspergillosis, histoplasmosis).
    • Viral pneumonia with lymphadenitis.
  • Inflammation:
    • Sarcoidosis (nodular thickening).
    • Hypersensitivity pneumonitis (peribronchovascular involvement).
  • Neoplasm:
    • Lymphangitic carcinomatosis (smooth or nodular thickening).
    • Lymphoma (diffuse or focal peribronchovascular involvement).
  • Circulatory:
    • Pulmonary edema (smooth peribronchovascular thickening).
    • Pulmonary hypertension.
  • Iatrogenic:
    • Post-radiotherapy fibrosis or nodularity.
  • Immune-related:
    • Eosinophilic granulomatosis with polyangiitis (EGPA).
• Recommendations:
  • Perform high-resolution CT to assess the size, extent, and morphology of peribronchovascular findings.
  • Consider bronchoscopy with lavage for infectious or inflammatory causes.
  • Use PET-CT to evaluate for malignancy or active granulomatous processes.
  • Correlate with clinical history and laboratory studies (e.g., markers for sarcoidosis or lymphoma).
• Key points and pearls:
  • Nodular thickening along bronchovascular bundles is a hallmark of granulomatous diseases like sarcoidosis or lymphangitic spread of cancer.
  • Smooth thickening is more commonly seen in pulmonary edema or lymphatic congestion.
  • Time-dependent changes, including resolution or progression, provide valuable clues to the underlying pathology.