Lymphangiography

Introduction & Anatomy - Lymphtastic Voyage

• Lymphangiography: Radiographic study of lymphatic vessels & nodes post-contrast injection.
• Purpose: Diagnose lymphatic obstruction, leaks (e.g., chylothorax, chylous ascites), guide interventions. Historically for staging.
• Key Anatomy:
  • Vessels: Superficial & deep lymphatics converge.
  • Cisterna chyli: Dilated sac at L1-L2 vertebrae; collects from lower limbs, pelvis, abdomen.
  • Thoracic duct: Main duct; from cisterna chyli, ascends, empties into left venous angle.
  • Right lymphatic duct: Drains right upper body into right venous angle.
  • Nodal groups: Inguinal, iliac, para-aortic, mediastinal, axillary.

⭐ Ethiodized oil (Lipiodol) allows visualization of lymph nodes for several weeks to months.

Indications & Contraindications - Green Light, Red Light

• Indications (Green Light):

  • Lymphoma Staging (Hodgkin's, NHL - historical, CT-missed nodes).
  • Occult Metastases (testicular, pelvic, prostate Ca, melanoma).
  • Lymphedema (primary/secondary, severity, pathway integrity).
  • Chylous Leaks (chylothorax, ascites, chyluria, fistulas).
  • Surgical Mapping (lymphatic bypass, node transfers).

• Contraindications (Red Light):

  • Absolute:
    • Severe iodine contrast allergy.
    • Severe pulmonary insufficiency (fatal oil embolism risk).
    • Local infection/cellulitis at injection site.
  • Relative:
    • Right-to-left cardiac shunt (↑ systemic embolism).
    • Bleeding disorders / anticoagulation.
    • Elderly, frail, or severely debilitated.

⭐ Historically key for lymphoma staging (Hodgkin's), now largely superseded by CT/PET-CT.

Procedure & Contrast - The Dyeing Art

• Step 1: Lymphatic Visualization & Access

  • Inject vital dye (e.g., Patent Blue V, 1-2 mL) intradermally between toes to stain pedal lymphatics.
  • After 15-20 min, small transverse incision over visible blue lymphatic on foot dorsum.
  • Carefully dissect, cannulate lymphatic with fine needle (e.g., 27-30G)/catheter; secure.

• Step 2: Contrast Administration

  • Agent: Ethiodized oil (Lipiodol Ultra-Fluide) - viscous, oil-based, slowly absorbed, provides prolonged opacification.
  • Dose: ~6-8 mL per leg for adults (max 10 mL), or 0.25 mL/kg; adjust for children.

  ⭐ Critical: Inject slowly at 0.1-0.2 mL/min per limb to prevent lymphatic rupture, pain, and oil extravasation into veins or tissues.

• Step 3: Imaging Sequence

*   Fluoroscopy: Guides injection, confirms intralymphatic placement, detects early extravasation.
*   24h Radiographs: Detail opacified lymph nodes (size, number, architecture).
*   Delayed Imaging: Assesses lymphatic channel patency, contrast clearance, or late pathology (e.g., thoracic duct).

Findings & Complications - Reading the Roads

Normal Appearance:

• Opacified nodes: uniform, foamy pattern.
• Intact lymphatic channels.

Abnormal Findings:

• Filling defects: Metastases, lymphoma.
• Nodal changes: Enlargement, altered architecture (e.g., mottling).
• Channel issues: Obstruction, collaterals, extravasation.

Lymphoma Interpretation:

• Nodal enlargement.
• Foamy, mottled, or reticular pattern.
• Filling defects.

⭐ The most common finding in lymphoma is nodal enlargement with a foamy, reticular pattern and filling defects.

Complications:

• Major: Pulmonary oil embolism (most serious ⚠️).
• Minor: Wound infection, contrast reaction, fever, lymphangitis.
• Rare: Chronic lymphedema.

Current Status:

• Largely replaced by CT, MRI, PET-CT, lymphoscintigraphy.
• Still used for: Specific indications like thoracic duct embolization.

High‑Yield Points - ⚡ Biggest Takeaways

• Lymphangiography uses Ethiodized oil (Lipiodol), an oil-based contrast, to visualize lymphatic system.
• Key uses: Identifying lymphatic leaks (chylothorax) and guiding thoracic duct embolization.
• Historically for lymphoma staging; now largely CT/MRI for this.
• Involves pedal lymphatic cannulation and slow Lipiodol injection.
• Serial X-rays over 24-48 hours show opacified nodes and thoracic duct.
• Major risk: Pulmonary oil embolism from oil-based contrast.
• Lipiodol persists in nodes for months, allowing delayed follow-up imaging.