Articles

Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

41 results found
Article

Adrenal vein sampling

Adrenal vein sampling (AVS) is a procedure where blood is collected from the adrenal veins via catheter to confirm autonomous hormone production, if it is unilateral or bilateral, and to guide further treatment. Indication AVS is commonly performed in primary aldosteronism, being indicated to ...
Article

Antonio Egas Moniz

Antonio Egas Moniz (1874-1955) 1 was a pioneering Portuguese neurologist that is notable in radiology history for his development of cerebral angiography in 1927. He is also known as the developer of prefrontal leucotomy (now better known as a lobotomy) ​for which he received a Nobel Prize in 1...
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Arteriovenous access

Arteriovenous access is required for haemodialysis in renal failure patients. The upper limb is generally preferred as a site, however, lower limb access can also be obtained. Ultrasound is the preferred modality for evaluation of the vessels prior to creating an access. Types arteriovenous fi...
Article

Carotid arterial stenting

Carotid arterial stenting (CAS) is a minimally invasive endovascular interventional procedure that can potentially offer the same advantage as surgery (carotid endarterectomy). Indications Indications for carotid stenting are evolving with endarterectomy trials that evaluate the carotid stenos...
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Catheter-directed thrombolysis

Catheter-directed thrombolysis (CDT) is an endovascular approach to the treatment of acute iliofemoral deep vein thrombosis. It involves the administration of a lytic agent directly into a thrombus.  Indications precise diagnosis of iliofemoral deep vein thrombosis  first episode of acute ili...
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Central venous catheter

Central venous catheters (CVC) or lines (CVL) refer to a wide range of central venous access devices but can broadly be divided into four categories. They may be inserted by medical, surgical, anaesthetic/ITU, or radiology specialists. Classification peripherally inserted central catheters (PI...
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Charles T Dotter

Charles T Dotter (1920-1985) is often considered the father of interventional radiology who in 1964 performed the very first peripheral angioplasty, and made many other major contributions in this field. Early life Charles Theodore Dotter was born in Boston on 14th June 1920. He graduated with...
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Coronary Artery Disease - Reporting and Data System

Coronary Artery Disease - Reporting and Data System (CAD-RADSTM) classification is proposed by the Society for Cardiovascular Computed Tomography (SCCT), the American College of Radiology (ACR), and the North American Society for Cardiovascular Imaging (NASCI), last updated in 2016. This recomm...
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Double lumen cannula for VV ECMO

The double lumen cannula enables veno-venous extracorporeal membrane oxygenation (VV ECMO) to patients with severe respiratory failure. It is often used as a bridge to lung transplant.  The cannulation is usually performed via the right jugular vein. This position allows the patients to stay aw...
Article

Endoleak

Endoleaks are characterised by persistent blood flow within the aneurysm sac following endovascular aneurysm repair (EVAR). Normally the aortic stent-graft used for EVAR excludes the aneurysm from the circulation by providing a conduit for blood to bypass the sac. Epidemiology An endoleak is a...
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Endovascular aneurysm repair

Endovascular aneurysm repair (EVAR) was first pioneered in the early 1990s. Since then technology of the devices has rapidly progressed and EVAR is now widely used as treatment of thoracic and abdominal aortic aneurysms (AAA). The advantages of endovascular repair over open repair are that they...
Article

Endovascular aneurysm sealing system (EVAS)

Endovascular aneurysm sealing system (EVAS) was developed with the intention to expand beyond the anatomic limitations of endovascular aneurysm repair (EVAR) devices, as well as to decrease the rates of re-intervention secondary to graft migration and type II endoleaks. EVAS was designed by End...
Article

Femoral artery pseudoaneurysm

Femoral artery pseudoaneurysms are usually iatrogenic as the femoral artery is the vessel of choice for most endovascular arterial interventions. Pathology Aetiology iatrogenic anticoagulation therapy inadequate compression following endovascular intervention improper arterial puncture tec...
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French gauge

The French gauge (Fr) (also known as the French scale or system) is used to size catheters, and other instruments, in interventional radiology and surgery. In some parts of the world, the Charrière (Ch) is used as the name of the unit, in honour of its inventor.  French sizing The French syste...
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Hepatic venous pressure gradient

Hepatic venous pressure gradient measurement is a safe and minimally invasive method to indirectly measure portal vein pressure in chronic liver disease patients suspected of developing portal vein hypertension.  Indications diagnosis of liver fibrosis and risk stratification identification o...
Article

Hickman catheter

Hickman catheters (or Hickman lines) are a type of tunnelled central venous access device. Indications chemotherapy administration 2 parenteral nutrition 2 long-term parenteral antibiotic administration 2 Complications Insertion arrhythmia (most common) 1 arterial injury kinking pneumo...
Article

Inferior vena cava filter

Inferior vena cava filter, or just IVC filter, is an endovascular device which is typically placed in the infrarenal inferior vena cava (IVC) to prevent pulmonary embolism in selected patients. This procedure is most often performed by interventional radiologists under fluoroscopic guidance. In...
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Infusothorax

Infusothorax is a complication of central venous catheter malposition where the catheter tip is located in the pleural space and the infusion of the fluid collects inadvertantly in the pleural space in the form of a pleural effusion. Longer term complications depend on the fluid being infused.
Article

Intra-aortic balloon pump

Intra-aortic balloon pumps (IABP) are used in the intensive care setting to provide haemodynamic assistance to patients in cardiogenic shock. Function and physiology The device is comprised of a catheter introduced via the femoral artery, which extends retrogradely to the proximal descending t...
Article

Jugular venous catheters

The internal jugular vein is a preferred site for venous access for large lumen, long-term central venous catheters for chemotherapy, haemofiltration and plasma exchange.  Typically, the right internal jugular is used as its vertical course straight down into the superior vena cava via the righ...
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Left paramediastinal catheter position (differential)

When a central venous catheter that is supposed to project over the superior vena cava is abnormally located to the left of the mediastinum a limited differential of left paramediastinal catheter position should be considered 1: located within a vein left sided superior vena cava left interna...
Article

May-Thurner syndrome

May-Thurner syndrome refers to a chronic compression of the left common iliac vein (CIV) against the lumbar vertebrae by the overlying right common iliac artery (CIA), with or without deep venous thrombosis 2. Although both left and right CIVs lie deep to the right common iliac artery, the left...
Article

Multiphase CT angiography in acute ischaemic stroke

Multiphase CT angiography is an evolving imaging technique in acute ischaemic stroke. The technique aims to quickly and reliably identify brain which is potentially salvageable with intervention. Brain tissue viability depends on many factors, with this technique assessing collateral leptomening...
Article

Needle gauge system

The needle gauge system, often called just the Gauge or G, is an internationally-used scale for sizing needles. It was adopted from pre-existing gauges which were used in industry to size metal wire. In contradistinction to the French scale, the other well-known sizing system, which is a metric...
Article

Onyx

OnyxTM is the trade name for a liquid embolic agent used in interventional radiology for the occlusion of blood vessels in embolisation therapy. It is an elastic copolymer (ethylene vinyl alcohol copolymer (EVOH)), dissolved in dimethyl-sulfoxide (DMSO). Micronised tantalum powder is also added ...
Article

Peripherally inserted central catheters

Peripherally inserted central catheters (PICC), often incorrectly termed PICC lines, are a type of central venous catheter predominantly used amongst oncology patients and those with chronic diseases (e.g. cystic fibrosis). They offer the ability to have long-term central venous access without ...
Article

Persistent communications between the carotid and vertebrobasilar arteries (mnemonic)

A mnemonic to recall the persistent communications between the anterior (carotid) and posterior (vertebrobasilar) systems is: HOT Pepper Knowledge of these anatomical variants is important to avoid confusion with pathology and to prevent inadvertent injury during surgery. Mnemonic H: hypoglo...
Article

Pinch off syndrome

Pinch-off syndrome is a spontaneous catheter fracture, which is seen as a complication of subclavian venous catheterisation. Epidemiology It is a known complication of central venous catheterisation with a much-reduced incidence in current practice and is generally considered to be rare. Radi...
Article

Portal vein embolisation

Portal vein embolisation (PVE) is a technique used to selectively occlude the blood supply to one of the liver lobes, diverting portal blood flow to the other lobe, the future liver remnant (FLR). This diversion will increase the size of the post hepatectomy future liver remnant (FLR) and increa...
Article

Post thrombotic syndrome

Post thrombotic syndrome (PTS) is a syndrome of chronic venous insufficiency following deep vein thrombosis (DVT) due to valvular incompetence, which results in chronic reflux and chronic venous hypertension. Epidemiology PTS is a common complication following extensive DVT of the limbs. Up to...
Article

Prostatic artery embolisation

Prostatic artery embolisation (PAE) is a minimally invasive procedure option utilised to treat the benign prostatic hyperplasia (BPH).  Indications PAE has been used for controlling prostatic haemorrhage (such as those associated prostate cancer) since 1970. However, its use in the treatment o...
Article

Pulmonary artery catheter

Pulmonary artery catheters (or Swan-Ganz catheters) are balloon flotation catheters that can be inserted simply, quickly, with little training and without fluoroscopic guidance, at the bedside, even in the seriously ill patient. Historically they were widely used to measure right heart haemodyna...
Article

Renal artery pseudoaneurysm

Renal artery pseudoaneurysms are uncommon vascular finding, with the majority occuring after a renal intervention. Pathology A renal artery pseudoaneurysm differs from a renal artery true aneurysm (as might occur in fibromuscular dysplasia) in that it does not involve all three layers of the a...
Article

Renal sympathetic denervation

Renal sympathetic denervation (RSDN), also known as renal denervation, is an interventional procedure that uses radiofrequency ablation to destroy the nerve endings in the wall of the renal arteries. Endovascular (trans-catheter) techniques are an alternative to surgical sympathectomy.  Indicat...
Article

Retroaortic left renal vein

Retroaortic left renal vein (RLRV) is a normal anatomical variant where the left renal vein is located between the aorta and the vertebra, and drains into the inferior vena cava. Its recognition is important in order to avoid complications during retroperitoneal surgery or interventional proced...
Article

Rotational vertebral artery occlusion syndrome

Rotational vertebral artery occlusion syndrome, also known as bow hunter's syndrome, is a rare form of vertebrobasilar insufficiency secondary to dynamic compression of the usually-dominant vertebral artery.  It has many predisposing aetiologies, but is most often due to large osteophytes, atla...
Article

TIPS evaluation

TIPS evaluation is useful to ensure that the shunt is working properly and that no stenosis has occurred within the stent. Ultrasound is often used as a first-line modality. Radiographic features Ultrasound The normal TIPS should show colour Doppler flow throughout its length. The in-stent ve...
Article

Transjugular intrahepatic portosystemic shunt

Transjugular intrahepatic portosystemic shunt (TIPS) is a treatment for portal hypertension in which direct communication is formed between a hepatic vein and a branch of the portal vein, thus allowing some proportion of portal flow to bypass the liver. The target portosystemic gradient after TI...
Article

Type III endoleak

A type III endoleak is a type of endoleak which usually occurs through a defect in the graft. It may be divided into two components.  IIIa: junctional separation of the modular components IIIb: fractures or holes involving the endograft Epidemiology It is relatively uncommon and only occurs ...
Article

Ultrasound guided peripheral intravenous cannulation

Peripheral intravenous cannulation under ultrasound guidance is the placement of a cannula into a peripherally located vein under the direct vision of ultrasound. This process allows the cannulation of veins that are unable to be visualised or palpated without ultrasound. In trained individuals ...
Article

Uterine artery embolisation

Uterine artery embolisation (UAE) is an interventional radiological technique to occlude the arterial supply to the uterus and is performed for various reasons. History Uterine artery embolisation has been practised for more than 20 years for controlling haemorrhage following delivery / aborti...

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