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.

159 results found
Article

Percutaneous transhepatic biliary drainage

Percutaneous transhepatic biliary drainage is an interventional radiology procedure undertaken for those with biliary obstruction. It is almost exclusively performed in those with a malignant obstruction, such as cholangiocarcinoma, ampullary and pancreatic malignancies when retrograde access v...
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Percutaneous transhepatic cholangiography

Percutaneous transhepatic cholangiography (PTC) is a radiographic technique employed in the visualization of the biliary tree and can be used as the first step in a number of percutaneous biliary interventions (e.g. percutaneous transhepatic biliary stent placement) Indications Purely diagnost...
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Peripherally inserted central catheter

Peripherally inserted central catheters (PICCs), often incorrectly tautologically 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...
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Periprocedural anticoagulation

When planning an interventional procedure a patient’s coagulation status must be assessed and optimized to best balance the risk of bleeding and thrombosis. The following must be considered; bleeding risks associated with the procedure medications the patient is taking that alter coagulation o...
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Peritoneal dialysis catheter

A peritoneal dialysis catheter is a flexible tube designed for peritoneal dialysis, the most well-known and widely-used being the Tenckhoff catheter.  History In 1968 an American nephrologist Henry A Tenckhoff (d.2017) 2 introduced his eponymous peritoneal indwelling catheter 1. The major impr...
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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...
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PHASES risk prediction score

The PHASES risk prediction score is a method of calculating the absolute 5-year risk of intracranial aneurysm rupture based on the data pooled from prospective cohort studies in the USA, Canada, Netherlands, Finland and Japan1. PHASES stands for: Population, Hypertension, Age, Size, Earlier suba...
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Pinch off syndrome

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

The popliteal artery is the direct continuation of the superficial femoral artery, at the point where it exits the adductor canal at the adductor hiatus, and passes into the popliteal fossa as the vessel courses posteriorly behind the knee. Summary origin: continuation of the superficial femor...
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Portal vein embolization

Portal vein embolization (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) which imp...
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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...
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Preoperative pulmonary nodule localization

Preoperative pulmonary nodule localization is a CT-guided procedure where a marker is applied to a usually small lung lesion to assist its surgical identification and resection. The widespread use of video-assisted thoracic surgery (VATS) and the advance in robotically assisted surgical interven...
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Prostatic artery embolization

Prostatic artery embolization (PAE) is a minimally invasive procedure option utilized to treat the benign prostatic hyperplasia (BPH).  Indications PAE has been used for controlling prostatic hemorrhage (such as those associated prostate cancer) since 1970. However, its use in the treatment of...
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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 hemodynam...
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Radioembolization

Radioembolization is the delivery of radioactive microspheres to cancers using an endovascular approach. It is often performed as an outpatient procedure.  Indications hepatocellular carcinoma hepatic metastases from colorectal carcinoma Contraindications Absolute contraindications excessi...
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Radiofrequency ablation

Radiofrequency ablation (RFA) is a medical procedure that uses a high-frequency alternating current produced by a radiofrequency generator oscillating in a closed loop circuit. This current heats a needle to over 60°C, which is used to cause intentional protein denaturation and tissue damage 1. ...
Article

Radiologically inserted gastrostomy (RIG)

A radiologically inserted gastrostomy (RIG) is a procedure where a tube is inserted percutaneously in the stomach, principally to provide nutritional support for patients with swallowing disorders 1. Indications inadequate oral intake due to dysphagia (neurologic disorder, oesophagal obstructi...
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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...
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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

Resuscitative endovascular balloon occlusion of the aorta

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a recently developed treatment for hemorrhagic shock used in major trauma patients with life-threatening abdominal or lower limb bleeding.  The aortic balloon is delivered on a catheter via the femoral artery in order to reduc...
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 procedu...
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Right atrial line

The right atrial (RA) line monitors RA pressure and is indicative of right ventricular function, preload and afterload. The RA line enters the right atrium through the right atrial appendage, and always exits the right side of the chest medial to the left atrial line. It is typically a double lu...
Article

Robotics in interventional radiology

Robotics in interventional radiology (IR) is an emerging area following the growth of engineering technology. Machine-assisted procedures are already performed in various disciplines including general, cardiothoracic and urologic surgery. The best-known is the Da Vinci® Surgical System. The appl...
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.  Pathology It has many predisposing etiologies, but is most often due to large osteoph...
Article

Sacroiliac joint injection

Sacroiliac joint injections can be performed using a posterior approach into the sacroiliac (SI) joint under fluoroscopic or CT guidance. It is often performed bilaterally. Indications diagnostic: relief of pain after injection of local anesthetic therapeutic: to relieve pain from degenerativ...
Article

Seldinger technique

The Seldinger technique is the mainstay of vascular and other luminal access in interventional radiology.  History The Seldinger technique was first described in 1953 by Sven-Ivar Seldinger (1921-1998), a pioneering Swedish interventional radiologist (a rare example of Stigler's law of eponymy...
Article

Selective internal radiation therapy

Selective internal radiation therapy (SIRT), also know as hepatic radioembolization, is a relatively new and developing modality for treating non-resectable liver tumors. The procedure consists of a transcatheter injection of radioactive particles via the hepatic artery.  It is generally consid...
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Shoulder injection (disambiguation)

Shoulder injection is a general term, especially for the patient, for a variety of procedures including: acromioclavicular joint injection glenohumeral joint injection glenohumeral (shoulder) arthrography glenohumeral (shoulder) hydrodilatation long head of biceps tendon sheath injection s...
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Sialography

Sialography is the imaging of the salivary glands, most commonly the parotid gland. The salivary ducts are conventionally examined fluoroscopically with high sensitivity, though cross-sectional imaging with CT or MR sialography has also been described. Indications suspected sialolithiasis or s...
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Sniff test

The fluoroscopic sniff test, also known as diaphragm fluoroscopy, is a quick and easy real time fluoroscopic assessment of diaphragmatic motor function (excursion). It is used most often to confirm absence of muscular contraction of the diaphragm during inspiration in patients with phrenic nerve...
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Spinal epidural injection

Epidural spinal injections are one of the more frequently performed spinal interventional procedures.Three approaches to the epidural space exist: transforaminal epidural injection interlaminar epidural injection cervical interlaminar epidural injection lumbar interlaminar epidural injection...
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Splenic biopsy

Percutaneous splenic biopsy, utilizing either ultrasound or CT guidance, is an accurate and reliable method of acquiring splenic tissue for histopathological assessment and has been proposed as an alternative for splenectomy in selected patients. Although the procedure has been historically fea...
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Splenic embolization

Splenic (artery) embolization is an endovascular technique for treatment of splenic and splenic artery pathology as an alternative to splenic artery ligation or splenectomy. It often results in successfully treating the underlying pathology, while maintaining at least partial splenic function.  ...
Article

Splenic trauma

Splenic trauma can occur after blunt or penetrating trauma or secondary to medical intervention (i.e. iatrogenic). The spleen is the most frequently injured internal organ after blunt trauma. Epidemiology In blunt trauma, the spleen can account for up to 49% of abdominal organ injuries 2. Cli...
Article

Stereotactic breast biopsy

Stereotactic breast biopsy refers to percutaneous sampling of breast tissue using mammographic guidance for targeting. Indications It is the biopsy method of choice when the finding of interest is best seen on mammography, such as microcalcifications (most common), architectural distortion, or...
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Subacromial bursal injection

Subacromial corticosteroid injection is reserved for patients with no response to initial treatment with impingement syndrome, subacromial bursitis and/or rotator cuff disorders. Nonsteroidal anti-inflammatory drugs (NSAIDs) and activity modification are the initial treatments to reduce the pain...
Article

Sunburst sign (renal angiomyolipoma)

The sunburst sign refers to the appearance of arterial blush seen at selective arterial DSA of a renal angiomyolipoma. Angiomyolipoma is a hypervascular renal mass that shows dense early arterial vascular network of tortuous irregular vessels with micro- or macroaneurysms.
Article

Superficial cervical plexus nerve block (ultrasound)

The superficial cervical plexus nerve block is a field block indicated for procedures involving, and anesthesia of, the anterolateral neck and the skin overlying the clavicle. The superficial cervical plexus (SCP) includes the greater auricular, lesser occipital, transverse cervical, and supracl...
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Sven-Ivar Seldinger

Sven-Ivar Seldinger (1921-1998), a Swedish radiologist, is primarily remembered for the invention of his revolutionary eponymous technique.  Early life Sven-Ivar Seldinger was born in Mora, Dalarna, Sweden on 19 April 1921 5. He attended medical school at the Karolinska Institute in Stockholm ...
Article

Symphyseal cleft injection

Symphyseal cleft injections (symphysography) are performed as both diagnostic and therapeutic measures for patients with (suspected) osteitis pubis, usually under CT or fluoroscopy.  Indications suspected or confirmed osteitis pubis Contraindications factors to be considered as per any muscu...
Article

Tachon syndrome

Tachon syndrome is a rare systemic side effect of epidural or intra-articular corticosteroid injections. Clinical presentation Minutes after injection, patients may complain of 1: acute low back pain chest tightness facial erythema profuse sweating cough agitation Treatment and prognosi...
Article

Thoracentesis

Thoracentesis, commonly known as a pleural tap or chest tap, is a procedure where excess pleural fluid is drained from the pleural space for diagnostic and/or therapeutic reasons. Ultrasound-guided thoracentesis performed by radiologists has been shown to have fewer complications than blind thor...
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Thoracic duct embolization

Thoracic duct embolization (TDE) is a safe, efficacious treatment for chylothorax 1. Chylothoraces with a low drain output (<1L/day) are traditionally managed conservatively with dietary change, while high output (>1L/d) are managed with surgical thoracic duct (TD) ligation 2.Thoracic duct embo...
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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 color Doppler flow throughout its length. The in-stent vel...
Article

Tracheobronchial stent

A tracheobronchial stent is a device used in the treatment of symptomatic airway compression. This device is inserted under bronchoscopic guidance in patients with external compression from mediastinal based malignancy, for example lung or esophageal cancers.  It may also be used in the treatme...
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Transcatheter arterial chemoembolisation

Transarterial chemoembolisation therapy (TACE) is a localized method of administrating chemotherapy directly to a liver tumor via a catheter study. The chemoembolic agent may be delivered via a mixture with LipiodolⓇ, known as conventional TACE, or as an injection of drug-eluting beads (DEB-TACE...
Article

Transforaminal epidural steroid injection

Transforaminal epidural steroid injections (TFESI), also known as transforaminal nerve root injection or nerve root blocks, are performed for treatment and diagnosis of radicular pain. They differ from selective nerve root blocks (SNRB), as the aim is to get "epidural spill" and get the injectat...
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...
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Transjugular renal biopsy

Transjugular renal biopsy can be performed to obtain an adequate tissue sample for histopathologic diagnosis on renal dysfunctions. It is usually performed in high-risk patients in whom percutaneous renal biopsy is not feasible or is contraindicated. This is also useful in morbidly obese patient...
Article

T tube cholangiogram

T-tube cholangiograms are a fluoroscopic study performed in the setting of hepatobiliary disease.  This technique has been largely superseded by MRCP and ERCP. Typically a T-shaped tube is left in the common bile duct at the time of surgery (e.g. cholecystectomy) and allows for exploration of t...
Article

Tumor ablation

Tumor ablation, or image-guided tumor ablation, is the direct application of chemical or energy-based (i.e. thermal and nonthermal) treatments to cause local tumor destruction. Techniques include: energy-based techniques thermal ablation radiofrequency ablation (RFA) microwave ablation (MWA)...
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 biopsy

Ultrasound-guided biopsy is one form of image-guided biopsy, typically performed by a radiologist. It is the most common form of image-guided biopsy, offering convenience and real-time dynamic observation with echogenic markers on cannulae allowing for precise placement. It can potentially be u...
Article

Ultrasound guided breast biopsy

Ultrasound guided percutaneous breast biopsy is a widely used technique for an accurate histopathological assessment of suspected breast pathology. It is a fast, safe and economical procedure. Indications Ultrasound guidance is limited to lesions visible on ultrasound study. Biopsy is generall...
Article

Ultrasound guided percutaneous drainage

Ultrasound guided percutaneous drainage is one form of image guided procedure, allowing minimally invasive treatment of collections that are accessible by ultrasound study. It has several advantages and disadvantages over CT, which include: Advantages is a dynamic study, allowing greater prec...
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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 visualized or palpated without ultrasound. In trained individuals ...
Article

Ultrasound-guided spinal anesthesia

With the growing incidence of obesity in the western world, ultrasound-guided anesthesia is becoming more common. Spinal anesthesia is traditionally administered by identifying relevant surface anatomy and imaging is rarely used for pre-procedural identification of structures.  Indications low...
Article

Ureteric stent

Ureteric stents, also known as double J stents or retrograde ureteric stents, is a urological catheter that has two "J-shaped" (curled) ends, where one is anchored in the renal pelvis and the other inside the bladder. Stents are used for the free passage of urine from the kidney to the bladder,...
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Urethral clamps

Various radiological and surgical instruments, including urethral clamps, have been developed to try to improve retrograde/ascending urethrogram (RUG/ASU) and voiding cystourethrogram (VCUG) technique in males. These are very rarely (if ever) used anymore. Brodny clamp This device has a metall...
Article

Urethrography

Urethrography refers to the radiographic study of the urethra using iodinated contrast media and is generally carried out in males. Terminology When the urethra is studied with instillation of contrast into the distal/anterior urethra it has been referred to as: retrograde urethrography (RUG)...
Article

Uterine artery embolization

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

Varicocele

Varicocele is the dilatation of the pampiniform plexus of veins, a network of many small veins found in the male spermatic cord. It is the most frequently encountered mass of the spermatic cord. Epidemiology The estimated incidence is at ~15% of the general male population and ~40% of subferti...
Article

Venous intravasation

Venous intravasation is the unintended introduction of radiographic contrast material into the local venous system. It is a well-recognized phenomenon during retrograde urethrograms 1,2 and hysterosalpingograms (HSG), although can occur with other invasive procedures in the vicinity of venous pl...
Article

Vertebroplasty

Vertebroplasty is an imaging-guided procedure which entails percutaneous injection of surgical polymethylmethacrylate (PMMA) cement into a diseased vertebral body. Vertebroplasty provides pain relief and strengthening of the bone of vertebrae weakened by disease. Indications It can be used as ...
Article

Watchman device

Watchman device is a permanent left atrial appendage closure device, which is percutaneously implanted to prevent embolization of thrombus from the appendage into the systemic circulation in cases atrial fibrillation. It is used when there is contraindication to anticoagulation or high risk of l...
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Woggle technique (interventional procedure)

The Woggle technique is the purse-string suture modified using to close a puncture site after a percutaneous procedure. Techniques common to all procedure include: a purse-string suture is done around the introducer sheath (the short plastic tube placed within a vein or artery) cut the needle...

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