Interventional radiology (IR) is a branch of clinical radiology utilising minimally-invasive image-guided procedures to diagnose and treat diseases.
To become an interventional radiologist, you should apply for ST1 clinical radiology training i.e. both interventional and non-interventional radiologists undertake the same initial training. There are small regional variations in training structure, but in general you will spend 3 years doing general diagnostic radiology (during which many schemes include 3-4 months of IR training), followed by 3 years of sub-speciality interventional radiology training, giving a total of 6 years training (1 year longer than diagnostic clinical radiology training).
Interventional radiology is generally sub-divided into into neuro IR and body/vascular IR. A minority of consultants perform a mixture of the both, but to my knowledge there are currently no training schemes which include both. This may change in the future with the increasing use of mechanical thrombectomy for stroke treatment. A large number of interventional radiologists will be needed to run this service and with no concurrent increase in the number of elective IR procedures, many centres will need to train body interventionists to undertake neuro intervention to help fill gaps in stroke thrombectomy rotas.
As far as body intervention goes (the majority of IR), there are a large range of procedures as follows:
Vascular IR covers approximately 60% of the work of interventional radiology. Most IR consultants call themselves vascular and interventional radiologists. The work is split up into:
- Diagnostic vascular imaging: MRI, CT, arterial Duplex, diagnostic angiography (which is becoming less common with improvements in cross-sectional imaging) and rarely PET CT.
- Peripheral vascular disease: Diagnostic angiography, angioplasty and stenting. Emergency work includes thrombectomy/thrombolysis for acute arterial and venous thrombosis.
- Aortic procedures: Infra-renal Endovascular Abdominal Aortic Aneurysm Repair (EVAAR), thoracic endovascular aortic repair, complex aortic repairs including fenestrated aneurysm repairs, thoraco-abdominal branched repairs, iliac branched repairs and complex thoraco-abdominal hybrid procedures usually for complicated aortic dissections. Emergency work includes EVAAR for aortic rupture (either traumatic or as a result of aneurysm).
- Visceral arterial work: Treatment of visceral aneurysms with either embolisation or exclusion with stent grafts. Visceral arterial stenting for ischeamia.
- Treatment of bleeding: e.g. from the GI tract, elective uterine fibroid embolisation or as an emergency in postpartum haemorrhage or traumatic arterial bleeding embolisation.
Vascular access services (PICC lines Porta-cath’s and Hickman lines) are provided by a range of different specialities including, specialist nurses, interventional radiologists, surgeons and anaesthetists. Most interventional radiologists are involved to a greater or lesser degree in vascular access.
Urology work is the second largest branch of IR.
- Treatment of urinary obstruction: Nephrostomy and ureteric stenting. This is performed in almost all IR units.
- Treatment of high burden of renal stone disease: Percutaneous Nephro-lithotomy (PCNL), only performed at specialist centres.
- Varicocele embolisation.
HepatobiliaryHepatobiliay work is generally higher risk than urological work and is less common, so is generally only performed at larger centres.
- Treatment of biliary obstruction: External biliary drains and biliary stenting.
- Trans-Jugular Intrahepatic PortoSystemic Shunting (TIPSS): Performed at specialist centres for portal hypertension causing bleeding or intractable ascites.
- Oesophageal and colonic stenting: Usually for inoperable cancer or as a bridge to surgery. Can be performed either soley by an interventional radiologist or together with an endoscopist.
- Radiologically inserted gastrostomy: Gastrostomy tube inserted under radiological guidance either under local anaesthetic or with sedation. These can be extended as gastro-jejunostomy tubes.
- Naso-gastric (NG) and naso-jejunal (NJ) tubes: Difficult NG tubes or naso-jejunal tubes can be inserted with radiological guidance. This is particularly useful when patients have had prior surgery such as a gastro-jejunostomy and you wish to manipulate the NJ tue into the efferent limb of the jejunum. Radiologists can also exchange gastrostomies for gasto-jejunostomies or create access to the stomach when there is no route orally.
Interventional OncologyThis is a huge growth area (no pun intended) in IR. Techniques are relatively new and indications expanding.
- Ablation: There are several competing technologies used to ablate tumours including radiofrequency ablation, microwave ablation and cryoablation. Tumours commonly ablated include, lung, liver, renal and bone.
- Embolisation: Either for symptom relief (e,g bleeding renal tumour) or for therapy as in hepatocellular cancer, this can involve bland (plastic/glass beads) or with particles impregnated with chemotherapy agents allowing high doses of chemotherapy to be targeted accurately at tumours.
- Selective internal radiotherapy (SIRT): A form of brachytherapy where either a whole organ or part of it can be targeted with radioactive particles. Most commonly the liver for inoperable HCC or metastaic colorectal cancer.
PaediatricIs quite specialised. In most hospitals, even large ones, this involves biopsies, drains and vascular access. In specialised children’s hospitals, there are many more procedures that may be performed, including treatment of lymphatic or venous malformations (usually with a sclerosant), treatment of renal hypertension by renal artery angioplasty or alcohol ablation of abnormally stenosed vessels, and bronchial dilatation. Any of the procedures performed in adults may be performed in children, but other conditions that may be commonly treated in adults are often rare in children.
Biopsy and drainageMany people do not consider biopsy as interventional radiology as it is a diagnostic rather than therapeutic procedure and most clinical radiologists (diagnostic) peform these, however in many centres a significant proportion of biopsies are performed by interventional radiologists.
- Percutaneous biopsy: Most commonly ultrasound guided, rarely CT or MRI guided.
- Trans-jugular biopsy: Biopsy of the liver or kidneys. Usually performed by an interventionist in patients with ascites or coagulopathy.
- Percutaneous drains using ultrasound or CT guidance.
How to apply for IR
The concise guide to all the common procedures in imaging on which a radiology trainee will be expected to be familiar.
A week in the life of an IR trainee
A week in the life of an IR consultant
- 3 sessions in the IR suite
- 1 session in theatre (EVAR or interventional oncology)
- 1 session vascular MDT
- 3 sessions general radiology reporting (CT, US, MRI, plain films etc)
- 1.5 sessions SPA
- 0.5-1 session for on-call commitments
Recommended websites to find out more
- British society of interventional radiology An excellent resource to find out about courses, conferences, essay prizes, bursaries and training opportunities. Become a member and you will also get access to the CVIR journal and ESIR website (see below). Look up the training committee and get involved! You can join as a student, junior doctor, or radiology trainee. https://www.bsir.org
- European society of radiology An excellent resource for cutting edge technologies and evidence base. I personally recommend the videos of almost all the talks from the annual CIRSE conference, delivered by world leading interventionists. https://www.esir.org/library/esir/home