Interventional radiology is a large, high-yield section covering vascular anatomy, embolisation, and angiographic technique. These free samples from the RadioQBank published set come with full explanations, exam pearls, and references.
Question 1 · Vascular Anatomy · easy
Michels classification is used to describe anatomical variations of which vascular structure?
- a. Renal artery origins and branching pattern
- b. Hepatic artery anatomy and its variants
- c. Coeliac axis and superior mesenteric artery relationship
- d. Portal vein tributaries and segmental drainage
Answer: B. The Michels classification (1966) systematically describes the 10 most common hepatic arterial anatomical variants, derived from a cadaveric study of 200 specimens. The classic (Type I) pattern — coeliac axis giving common hepatic artery → proper hepatic artery → right and left hepatic arteries — occurs in only ~55% of individuals. Variants include replaced right hepatic from SMA (Type III, ~11%), replaced left hepatic from left gastric artery (Type II, ~10%), replaced common hepatic from SMA (Type V, ~2.5%), and other combinations. Knowledge of Michels types is essential before hepatic IR procedures (TACE, HAE, RFA guidance), liver transplantation, and hepatic surgery to avoid inadvertent vessel injury.
Exam pearl: Michels = hepatic artery variants (10 types). Type I normal = 55%. Most common variant = replaced RHA from SMA (Type III).
Michels NA. Blood Supply and Anatomy of the Upper Abdominal Organs. 1955; Kandarpa IR Handbook 5th ed
Question 2 · Paediatric IR · easy
A 5-year-old boy has a macrocystic lymphatic malformation in the right axilla. Sclerotherapy with bleomycin is planned. Which of the following is the most important safety consideration unique to bleomycin used as a sclerosant?
- a. Cumulative dose limit to minimise risk of pulmonary fibrosis
- b. Pre-treatment with corticosteroids to prevent anaphylaxis
- c. Avoidance in patients with renal failure due to nephrotoxicity at sclerotherapy doses
- d. Monitoring for cardiac arrhythmias during injection
Answer: A. Bleomycin is an antineoplastic antibiotic used as a sclerosant for lymphatic and venous malformations. Its primary safety concern is pulmonary fibrosis, which is dose-dependent and cumulative. At the doses used for sclerotherapy (1 unit/kg per session, maximum 15 units/session), pulmonary toxicity is rare, but cumulative lifetime dose must be tracked. The threshold for significant pulmonary toxicity in oncology is 400 units total; sclerotherapy doses are far lower, but tracking is still required.
Exam pearl: Bleomycin: track cumulative dose; pulmonary fibrosis risk; worse with renal impairment and supplemental O2.
JVIR 2020; Radiographics 2018; Kandarpa IR Handbook 5th ed
Question 3 · Bronchial Artery Anatomy · moderate
A 61-year-old man with haemoptysis undergoes bronchial artery embolisation (BAE). DSA of the descending thoracic aorta shows a right intercostobronchial trunk (RICBT). Which of the following best describes this variant?
- a. A common trunk giving rise to the right bronchial artery and the right 5th intercostal artery
- b. A common trunk giving rise to the right bronchial artery and a right intercostal artery, typically between T3 and T8
- c. A direct origin of the right bronchial artery from the right subclavian artery
- d. A common trunk for both right and left bronchial arteries from the aortic arch
Answer: B. The right intercostobronchial trunk (RICBT) is the most common bronchial artery variant, occurring in approximately 70–80% of people. It is a single trunk arising from the descending thoracic aorta (typically between T3 and T8, most often at T5–T6) that supplies both the right bronchial artery and one of the right intercostal arteries. This shared origin is critical during BAE — inadvertent embolisation of the intercostal component can cause spinal cord ischaemia if it gives rise to an anterior spinal artery (artery of Adamkiewicz).
Exam pearl: RICBT = right bronchial + intercostal artery single trunk at T5–T6 — check for anterior spinal artery before BAE.
Kandarpa & Machan IR Handbook 5th ed; Radiographics 2002;22(6):1395–1409
Question 4 · Angiography · moderate
A 5 Fr Berenstein catheter is introduced via the right femoral artery for cerebral angiography. The right common carotid artery is selected from the aortic arch. Which aortic arch type is associated with the highest technical difficulty and risk of neurological complication during arch vessel catheterisation?
- a. Type I arch
- b. Type II arch
- c. Type III arch
- d. Bovine arch variant
Answer: C. The aortic arch is classified by the relationship of the great vessel origins to the outer curvature of the aortic arch. Type I: all three vessels originate within one vessel-width from the outer curvature (easy, parallel origin). Type II: origins 1–2 vessel widths below outer curvature (moderate difficulty). Type III: origins > 2 vessel widths below outer curvature — the arch is elongated/tortuous (most common in elderly, hypertensive patients), making it extremely difficult to engage branch vessels with standard catheters. Type III arches require specialised reversed-curve catheters (Simmons, VTK) and are associated with the highest risk of embolic neurological complications due to catheter/wire manipulation in the arch.
Exam pearl: Type III arch = origins > 2 vessel widths below outer curvature = hardest to catheterise. Use Simmons/VTK catheter. Highest neurological complication risk.
Radiographics 2004;24:647 — Aortic arch variants; AJNR 2010;31:1106
Question 5 · Embolisation — Epistaxis · hard
A 47-year-old woman undergoing embolisation for intractable epistaxis develops severe facial pain and trismus 2 days post-procedure. CT face shows devascularisation of the masseter muscle and temporomandibular joint region. Which embolic agent was most likely responsible, and what is the pathophysiology?
- a. Gelfoam — mechanical non-permanent occlusion causing ischaemia
- b. Small PVA particles (<150 µm) — penetrated collaterals to masseter branches causing deep tissue ischaemia
- c. Large coils — mechanical compression of trigeminal nerve
- d. N-butyl cyanoacrylate (NBCA) — adhesive migration to pterygoid plexus
Answer: B. Use of small PVA particles (<150–300 µm) during IMA embolisation can result in deep penetration through vascular anastomoses into small muscular branches supplying the masseter, temporalis, and TMJ region, causing tissue ischaemia, trismus, jaw necrosis, and pain. This is a well-recognised complication of over-distal embolisation with small particles. Standard practice mandates using particles >300 µm (typically 355–500 µm) for epistaxis to avoid this and the risk of ophthalmic anastomotic embolisation.
Exam pearl: Trismus post-epistaxis embolisation = small particle non-target embolisation to masseter; always use PVA ≥355 µm.
Cardiovasc Intervent Radiol 2017;40(11):1682–1691; Kandarpa & Machan 2nd ed
Question 6 · Embolisation — Trauma · hard
A trauma patient has a hepatic grade IV laceration with a contrast blush on arterial phase CT. During hepatic angiography, no active extravasation is seen. What is the most likely explanation and what should the operator do?
- a. CT was a false positive — terminate procedure
- b. Vasospasm has temporarily stopped bleeding — proceed with empirical embolisation of the right hepatic artery
- c. Perform selective injection of right and left hepatic arteries with fluoroscopic subtraction; look for vessel irregularity, pseudoaneurysm, or AV fistula
- d. Repeat CT to reconfirm extravasation before proceeding
Answer: C. Active arterial haemorrhage can be intermittent — vasospasm induced by the catheter, hypotension, or clot formation can temporarily stop extravasation at the time of angiography. In this scenario, the operator should perform systematic superselective injection of right and left hepatic artery branches with digital subtraction angiography, looking for indirect signs of injury: vessel irregularity, pseudoaneurysm formation, arteriovenous fistula, or truncated vessel. Empirical embolisation based on CT findings is appropriate if no active blush is seen but CT confirms injury with extravasation.
Exam pearl: CT blush but negative angiography = vasospasm; systematically inject hepatic artery branches for pseudoaneurysm/AV fistula — empirical embolisation if CT strongly confirms injury.
Kandarpa & Machan 2nd ed; Radiographics 2014;34(3):740–757