Ch19: Interventional Radiology（介入放射学）

# Ch19: Interventional Radiology（介入放射学）

Preparatory Mindset

Interventional radiology (IR) is defined (Wallace, 1976) as a specialty where radiologists use imaging techniques or modalities to guide percutaneous invasive diagnostic and therapeutic procedures. Compared with traditional open surgery it is simpler, safer, minimally invasive, less painful and cost-effective; in some fields IR has almost displaced open surgery. The exam asks: What is IR? What do interventional radiologists do? Non-vascular vs vascular interventional radiology, and the Seldinger technique.

Core Concepts

History milestones

• 1895 Wilhelm Roentgen — discovery of X-rays.
• 1929 Forssmann — first cardiac catheter (experiment on himself; Nobel 1950).
• 1953 Seldinger — Seldinger technique for safe vascular access (needle → guidewire → sheath/catheter).
• 1964 Charles T. Dotter — first interventional operation (transluminal angioplasty with coaxial catheters); "catheters should replace scalpels"; the father of interventional radiology.
• 1974–1975 Andreas Gruentzig — double-lumen balloon catheter → first PTA of coronary artery.
• 1967 Margulis coined the term "interventional"; 1976 Wallace's definition.
• Tools: Amplatz (guidewires, thrombectomy devices), Gianturco (occlusive coils, IV filters, expandable stents).
• In China: started 1970s; 1996 IR established as an independent diagnosis-and-treatment subject alongside internal medicine and surgery.

Seldinger technique

• Stepwise: needle puncture → guidewire through needle → remove needle → sheath/catheter over guidewire → exchange for final catheter.
• Safe access to blood vessels and other hollow organs.

Categories

• Cardiac IR, neural IR, tumor IR, peripheral IR.

Non-vascular interventional procedures

• Percutaneous CT/US-guided biopsies and oncotherapy (biopsy with special puncture needle under imaging guidance).
• Tumor ablation: direct injection of drugs or physical stimuli via a puncture needle under imaging guidance to make tumor cells necrose; implantation of radioactive seeds.
• Percutaneous drainage (e.g. drainage of liver abscess: catheter into the cyst/abscess to drain fluid).
• Biliary intervention: percutaneous removal of retained biliary stones; biliary drainage catheters; biliary tract stenting (malignant obstruction — e.g. pancreatic cancer with jaundice: direct bilirubin 35.1 µmol/L → percutaneous transhepatic biliary drainage/stent instead of surgery).
• Urologic intervention: internal/external nephrostomy drainage, percutaneous stone extraction, urethral dilation and stenting (e.g. post-trauma difficulty urinating).
• Tracheal/bronchial intervention: tracheal/bronchial stents when the airway is narrowed or blocked (e.g. post-surgical lung cancer recurrence with SOB, oxygen saturation 50–60%).
• Alimentary canal intervention: GI stents (e.g. esophageal carcinoma with dysphagia and weight loss → esophageal stent).
• Fallopian tube recanalization; orthopedic intervention.

Vascular interventional procedures

• Angiography (diagnosis), angioplasty (widen obstructed vessels — PTA), stenting, embolization (stop irregular blood flow/inhibit a non-working organ; e.g. vertebral hemangioma, GI bleeding), chemoembolization (deliver cancer treatment agents to a tumor — TACE for HCC), thrombolysis (navigate and dissolve blood clots), IVC filters, coils, TIPS (transjugular intrahepatic portosystemic shunt for portal hypertension/varices).

Clinical examples (cases from lecture)

1. HCC/liver mass → biopsy → ablation or TACE.
2. Liver abscess/cyst → percutaneous drainage (do not cut it out).
3. Pancreatic cancer + obstructive jaundice → biliary drainage + stent.
4. Post-trauma urinary retention → nephrostomy/urethral stent.
5. Lung cancer recurrence + airway obstruction → tracheal/bronchial stent.
6. Esophageal cancer + dysphagia → esophageal stent.

High-Yield Points

• Key Point: IR = image-guided percutaneous diagnostic and therapeutic procedures (Wallace definition).
• Key Point: Seldinger technique (1953): needle → guidewire → sheath → catheter.
• Key Point: Dotter (1964) = father of IR (transluminal angioplasty); Gruentzig = balloon angioplasty/PTCA.
• Key Point: Non-vascular IR: biopsy, ablation, drainage, biliary/urologic/airway/GI stents, fallopian tube recanalization.
• Key Point: Vascular IR: angiography, angioplasty, stenting, embolization, chemoembolization (TACE), thrombolysis, IVC filter.
• Key Point: Advantages: simpler, safer, minimally invasive, less pain, cost-effective.

Topic Summary

IR uses imaging to guide percutaneous diagnostic and therapeutic procedures (biopsy, drainage, ablation, stenting, angioplasty, embolization, chemoembolization, thrombolysis). History: Seldinger (1953) → Dotter (1964, father of IR, angioplasty) → Gruentzig (balloon, PTCA). Non-vascular: biopsies, ablation, drainage (abscess/biliary), airway/GI/urologic/biliary stents, fallopian tube recanalization. Vascular: angioplasty, stents, coils, embolization, TACE, thrombolysis, IVC filters. Clinical cases: HCC (biopsy/TACE), obstructive jaundice (biliary drainage/stent), airway and esophageal obstruction (stents), post-trauma urologic obstruction (nephrostomy/urethral stent).