Interventional radiology procedures

Interventional radiology procedures

Interventional radiology procedures

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Intro to IR - Needles, Wires, & Access

  • Access Core: Needles → Wires → Catheters/Sheaths.
  • Needles: For initial puncture.
    • Types: Beveled (Francine), Cutting (Chiba), Trocar (sharp stylet).
  • Guidewires: Rail for catheter passage.
    • J-tip: Atraumatic, avoids intimal injury.
    • Glidewire: Hydrophilic coating for tight lesions.
  • Catheters: Sized in French units ($1\text{ Fr} = 1/3\text{ mm}$).

Seldinger Technique Steps

⭐ The Seldinger technique is the cornerstone of gaining safe vascular and non-vascular access.

Vascular Procedures - Plumbing & Blockages

  • Angioplasty & Stenting:

    • Mechanically widens stenotic vessels (e.g., atherosclerosis, fibromuscular dysplasia).
    • Procedure: A balloon is inflated within the vessel, often followed by placing a metal stent to maintain patency.
    • Key Indications: Peripheral artery disease (PAD), renal artery stenosis (RAS), coronary artery disease (CAD).
  • Catheter-Directed Thrombolysis & Thrombectomy:

    • Targets acute blockages from clots.
    • Thrombolysis: Infuses a fibrinolytic agent (e.g., tPA) directly into the thrombus.
    • Thrombectomy: Aspirates or mechanically destroys the clot.
    • Indications: Acute limb ischemia, massive pulmonary embolism (PE), extensive deep vein thrombosis (DVT).
  • Embolization:

    • Deliberate occlusion of a blood vessel to stop flow.
    • Agents: Coils, particles, glue.
    • Uses: Control active bleeding (trauma, GI bleed), treat tumors (chemoembolization), uterine fibroid embolization (UFE).

Angiogram: Coil embolization of bleeding visceral artery

TIPS Procedure: The Transjugular Intrahepatic Portosystemic Shunt (TIPS) creates a low-resistance channel between the portal vein and a hepatic vein. This decompresses the portal system but can precipitate or worsen hepatic encephalopathy by shunting ammonia-rich blood past the liver.

Non-Vascular Work - Biopsies, Drains, & Ablations

  • Image-Guided Biopsy

    • Types: Core needle (histology) vs. Fine-Needle Aspiration/FNA (cytology).
    • Guidance: Ultrasound (real-time, no radiation), CT (superior resolution), or MRI.
    • Indications: Characterize masses (e.g., liver, lung, kidney, thyroid).
    • Contraindications: Uncorrectable coagulopathy, unsafe access path.
  • Percutaneous Drainage

    • Purpose: Evacuate fluid collections (e.g., abscesses, seromas, bilomas).
    • Technique: Seldinger technique is standard for catheter placement.
    • Management: Monitor output quality/quantity; flush to maintain patency.

⭐ In abscess drainage, successful therapy is marked by decreasing, less purulent output (e.g., purulent → serosanguinous).

  • Tumor Ablation
    • Goal: Destroy unresectable tumors (HCC, RCC, lung mets).
    • Modalities:
      • Radiofrequency (RFA): Frictional heat.
      • Microwave (MWA): Faster, larger zones, resists heat sink.
      • Cryoablation: Freeze/thaw cycles induce cell death.

CT-guided core needle biopsy of liver lesion

IR Safety - Contrast & Complications

  • Iodinated Contrast:
    • Contrast-Induced Nephropathy (CIN): Risk ↑ if eGFR < 30. Prevent with robust IV hydration.
    • Allergic-like Reactions: Premedicate patients with a prior reaction using corticosteroids.
  • Gadolinium Contrast:
    • Nephrogenic Systemic Fibrosis (NSF): High risk in severe renal dysfunction (eGFR < 30).

⭐ Hold Metformin for 48h post-contrast if eGFR < 30 or in acute kidney injury (AKI). This prevents potential for lactic acidosis.

High‑Yield Points - ⚡ Biggest Takeaways

  • Transjugular Intrahepatic Portosystemic Shunt (TIPS) treats refractory ascites or variceal bleeding but risks worsening hepatic encephalopathy.
  • Catheter-directed embolization is a primary treatment for acute hemorrhage, such as in GI bleeds or pelvic trauma.
  • Percutaneous drainage is preferred over open surgery for most abdominal abscesses.
  • Percutaneous nephrostomy provides emergent decompression for an obstructed urinary system, especially with infection.
  • IVC filters are for pulmonary embolism prophylaxis when anticoagulation is contraindicated.

Practice Questions: Interventional radiology procedures

Test your understanding with these related questions

A 62-year-old man comes to the emergency department for severe, acute right leg pain. The patient's symptoms began suddenly 4 hours ago, while he was reading the newspaper. He has poorly-controlled hypertension and osteoarthritis. He has smoked one pack of cigarettes daily for 31 years. Current medications include lisinopril, metoprolol succinate, and ibuprofen. He appears to be in severe pain and is clutching his right leg. His temperature is 37.4°C (99.3°F), pulse is 102/min and irregularly irregular, respirations are 19/min, and blood pressure is 152/94 mm Hg. The right leg is cool to the touch, with decreased femoral, popliteal, posterior tibial, and dorsalis pedis pulses. There is moderate weakness and decreased sensation in the right leg. An ECG shows absent P waves and a variable R-R interval. Right leg Doppler study shows inaudible arterial signal and audible venous signal. Angiography shows 90% occlusion of the right common femoral artery. In addition to initiating heparin therapy, which of the following is the most appropriate next step in management?

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Flashcards: Interventional radiology procedures

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_____ is a thin protrusion of esophageal mucosa, most often in the upper esophagus

TAP TO REVEAL ANSWER

_____ is a thin protrusion of esophageal mucosa, most often in the upper esophagus

Esophageal web

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