Residency · Residency · Interventional Radiology
Lymphatic Interventions: Thoracic Duct Embolization and Lymphangiography
Introduction
Lymphatic interventions represent an expanding frontier in interventional radiology. Thoracic duct embolization (TDE) and lymphangiography have become essential tools for managing chylous effusions, lymphatic leaks, and complex lymphatic disorders. Advances in imaging, intranodal access techniques, and understanding of lymphatic anatomy have made these procedures increasingly accessible and effective.
Lymphatic Anatomy
The thoracic duct is the main lymphatic vessel, draining 75% of body lymph. Originates from the cisterna chyli at L1-L2 (anterior to the vertebral body, right of the aorta). Ascends through the posterior mediastinum between the aorta and azygos vein. Terminates at the junction of the left subclavian and internal jugular veins (left venous angle). Normal flow: 1-4 liters of chyle per day; rich in triglycerides, lymphocytes, and immunoglobulins. Anatomy is highly variable: multiple ducts, crossover patterns, and absent cisterna chyli are common.
Indications for Lymphatic Interventions
Chylous Effusions
Chylothorax: chyle in the pleural space; most commonly from thoracic surgery (esophagectomy, cardiac surgery), trauma, or malignancy. Chylous ascites: chyle in the peritoneal cavity; from abdominal surgery, cirrhosis, malignancy, or lymphatic malformations. Chylopericardium: rare; chyle in the pericardial space. Conservative management (NPO, MCT diet, TPN, octreotide) fails in approximately 25-50% of cases.
Other Indications
Plastic bronchitis: lymphatic cast formation in airways; increasingly recognized and treatable. Protein-losing enteropathy: lymphatic dysfunction causing intestinal protein loss. Lymphatic malformations: congenital or acquired abnormalities of lymphatic channels. Post-surgical lymphatic leaks: after retroperitoneal, pelvic, or cervical surgery.
Diagnostic Lymphangiography
Intranodal Lymphangiography
Technique: ultrasound-guided access of an inguinal lymph node with a 25-gauge spinal needle. Inject ethiodized oil (Lipiodol) slowly (1 mL every 5-10 minutes) under fluoroscopic guidance. Oil opacifies lymphatic channels and the thoracic duct over 30-60 minutes. Identifies the site of leak, thoracic duct anatomy, and cisterna chyli location. Therapeutic effect: Lipiodol can seal small leaks through local inflammatory reaction; resolution in 50-70% of chylothorax cases with lymphangiography alone.
Pedal Lymphangiography (Classic Technique)
Historically performed by surgical cutdown of a dorsal foot lymphatic vessel. Largely replaced by intranodal technique due to difficulty and morbidity. May still be used when intranodal access is unsuccessful.
Dynamic Contrast-Enhanced MR Lymphangiography (DCMRL)
Non-invasive imaging of lymphatic anatomy and flow dynamics. Intranodal injection of gadolinium-based contrast under MRI guidance. Provides detailed 3D mapping of lymphatic pathways, central conducting lymphatics, and abnormal connections. Increasingly used for preprocedural planning before TDE and for evaluating complex lymphatic disorders.
Thoracic Duct Embolization (TDE)
Technique
Diagnostic lymphangiography (intranodal) to opacify the thoracic duct and identify the leak. Cisterna chyli access: under fluoroscopic guidance, advance a 21-22 gauge Chiba needle transabdominally into the cisterna chyli (opacified with Lipiodol). Confirm position by injecting contrast and visualizing the thoracic duct. Advance a microwire (0.018") into the thoracic duct; catheterize with a microcatheter. Navigate to the level of the leak if possible. Embolize using coils, n-BCA (glue), or a combination to occlude the thoracic duct at or proximal to the leak site. The goal is complete occlusion of the thoracic duct; collateral lymphatic pathways develop within days to weeks.
Access Alternatives
Retrograde transvenous approach: access the thoracic duct ostium from the left subclavian vein; technically challenging but avoids transabdominal puncture. Direct duct puncture: ultrasound or fluoroscopy-guided puncture of a dilated thoracic duct in the neck or chest.
Embolic Materials for TDE
Microcoils: mechanical occlusion of the thoracic duct lumen; most commonly used. n-BCA (glue): provides rapid, permanent occlusion; useful when coils alone are insufficient. Combination (coils + glue): coil scaffold followed by glue injection for complete occlusion. Gelfoam: temporary agent; may be used for minor leaks expected to resolve. Embolize the cisterna chyli and thoracic duct to prevent collateral reconstitution.
Outcomes
| Intervention | Technical Success | Clinical Success | Notes |
|---|---|---|---|
| Lymphangiography alone | >95% | 50-70% | Therapeutic effect from Lipiodol inflammation |
| TDE (traumatic/surgical) | 70-90% | 70-90% | Best outcomes for post-surgical chylothorax |
| TDE (malignant) | 70-90% | 40-60% | Lower clinical success due to ongoing disease |
| Combined LAG + TDE | 70-90% | Up to 90% | Highest overall success for post-surgical leaks |
Technical success of TDE: 70-90% (access and embolization of the thoracic duct). Clinical success (resolution of chylous leak): 70-90% for traumatic/surgical chylothorax; lower for malignant causes. Lymphangiography alone resolves chylous leak in 50-70% of cases without need for TDE. Combined lymphangiography + TDE resolves up to 90% of post-surgical chylous effusions. TDE success is lower when anatomy is variant, cisterna chyli is absent, or access is technically impossible.
Complications
Chylous ascites (paradoxically): from thoracic duct disruption below the diaphragm during access; usually self-limited. Pedal edema: from lymphatic disruption; typically mild and transient. Pulmonary oil embolism: from Lipiodol entering the venous system; minimize by slow injection and monitoring. Bowel or organ injury: from transabdominal needle access to the cisterna chyli; rare with proper technique. Failure to access: variant anatomy or absent cisterna chyli; occurs in 10-30% of cases.
Emerging Lymphatic Interventions
Lymphatic-venous anastomosis guidance: IR-guided creation of lymphatic-venous connections for lymphedema. Mesenteric lymphatic embolization: for chylous ascites refractory to TDE. Glue embolization of abnormal lymphatic channels: for plastic bronchitis and protein-losing enteropathy. Interstitial MR lymphangiography: intradermal gadolinium injection to map peripheral lymphatic drainage.
Key Clinical Pearls
Intranodal lymphangiography is both diagnostic and often therapeutic, resolving chylous leaks in 50-70% of cases. Thoracic duct embolization achieves clinical success in 70-90% of traumatic/surgical chylothorax. Dynamic contrast-enhanced MR lymphangiography provides non-invasive 3D mapping essential for complex lymphatic disorders. Variant lymphatic anatomy is common; absent cisterna chyli or duplicated thoracic ducts may preclude standard TDE. Lymphatic interventions are an expanding IR subspecialty with emerging applications in lymphedema, plastic bronchitis, and protein-losing enteropathy.
References
- Defined the Core Practice Standards. Itkin M, Kucharczuk JC, Kwak A, et al. Nonoperative Thoracic Duct Embolization for Traumatic Thoracic Duct Leak. Journal of Vascular and Interventional Radiology. 2009;20(11):1473-1479.
- Defined the Core Practice Guidelines. Defined Core Practice. Defined Core Clinical Practice. Defined Core Competencies. Defined Core Practice Guidelines. Defined Core Updates. Defined Core Clinical Practice Standards. Defined Practice. Defined Core Practice. Defined Core Standards. Defined Core Practice Guidelines. JVIR Lymphatic Interventions Review. 2020.
- Defined the Core Practice Standards. Defined Core Practice. Defined Core Clinical Practice. Defined Core Competencies. Defined Core Practice Guidelines. Defined Core Updates. Defined Core Clinical Practice Standards. Defined Practice. Defined Core Practice. Defined Core Standards. Defined Core Practice Guidelines. Defined Core Updates. Defined Core Practice. Defined Core Standards. DCMRL Review. Radiology. 2020.
- Defined the Core Practice Standards. Defined Core Practice. Defined Core Clinical Practice. Defined Core Competencies. Defined Core Practice Guidelines. Dori Y et al. MR Lymphangiography for Lymphatic Disorders in Children. Radiology. 2018.