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.

170 results found
Article

Esophageal intubation

Esophageal intubation refers to the incorrect placement of an endotracheal tube in the esophagus. Within minutes its consequences can be catastrophic with the seriousness of its outcome depending largely on the timeliness of its diagnosis. Epidemiology Accidental esophageal intubation can happ...
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Esophageal stent

Esophageal stents are a treatment option in patients with esophageal strictures. It is most commonly used for symptomatic relief in those with dysphagia secondary to malignancy. The stent is typically covered in nature and inserted endoscopically or fluoroscopically. The distal esophagus is the ...
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Onyx

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

Ovarian vein embolization is an interventional technique primarily used towards the treatment of varicosities. Indications The main indications are: as part of management of pelvic congestion syndrome 1-4 to treat pelvic varicosities diagnosed by imaging to treat labial and/or perineal vari...
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Patent track sign (ultrasound)

Patent track sign is a finding on color Doppler ultrasound, representing blood traveling along the course a biopsy needle track. It can occur after a biopsy of any organ, but is more often seen after liver or kidney biopsies. Radiographic findings linear color Doppler flow along the course of ...
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Pelvic abscess

A pelvic abscess refers to a walled-off collection of pus in the pelvis. Pathology  Etiology Some of the causes include: pelvic inflammatory disease (tubo-ovarian abscess) iatrogenic e.g. post surgical inflammatory bowel disease pelvic actinomycosis infection diverticulitis Clinical pre...
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Percutaneous cholecystostomy

Percutaneous cholecystostomy is an image-guided placement of drainage catheter into gallbladder lumen. This minimally invasive procedure can aid the stabilization of a patient to enable a more measured surgical approach with time for therapeutic planning. A 2018 study 11 demonstrate no differen...
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Percutaneous endoscopic gastrostomy

Percutaneous endoscopic gastrostomy (PEG) is a procedure where a flexible feeding tube (commonly known as a PEG tube) is inserted through the abdominal wall and into the stomach. This may be placed under endoscopic or radiological guidance, in the latter, the procedure may be known as a percutan...
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Percutaneous nephrolithotomy

Percutaneous nephrolithotomy (PCNL) is a surgical procedure for the extraction of large renal calculi. It is usually performed in the operating theater either by a urologist or combined urologist-radiologist team. Indication PCNL is used to destroy and remove renal calculi, typically over 2 cm...
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Percutaneous nephrostomy

Percutaneous nephrostomy is a technique in which percutaneous access to the kidney is achieved under radiological guidance. The access is then often maintained with the use of an indwelling catheter. Indications Percutaneous nephrostomy is usually reserved for when retrograde approaches are un...
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Percutaneous nephrostomy salvage and tube exchange

Percutaenous nephrostomy salvage and tube exchange are two procedures undertaken in those with long term nephrostomies. These patients are often either unsuitable or do not wish to have ureteric stenting to relieve their urinary tract obstruction. Nephrostomy salvage Nephrostomy salvage is und...
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Percutaneous renal biopsy

Percutaneous renal biopsy, utilizing either ultrasound or CT, allows for an accurate, reliable method of acquiring renal tissue for histopathological assessment. The biopsy may be of a native or transplant kidney. It is divided into two types: non-focal or non-targeted focal or targeted (i.e....
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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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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 ablation syndrome

Post-ablation syndrome occurs from 24 to 48 hours following ablation and lasts no longer than 10 days 1. It is believed to occur following cytokine release and tumor necrosis, causing patient fever and flu-like symptoms. If symptoms persist following 10 days after the procedure, alternate diagn...
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Post-embolization syndrome

Post-embolization syndrome (PES) is one of the most common side effects of transarterial embolization and chemoembolization. It comprises of a constellation of fever, nausea/vomiting, and pain. It is often a self-limiting phenomenon and usually occurs within the first 72 hours after embolization...
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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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Prostate biopsy

Transrectal ultrasound–guided biopsy is considered the standard approach for prostate biopsy and is most commonly performed on an outpatient with a positive screening for prostate cancer.  Nowadays, with the MRI capacity for depicting abnormal areas of the prostate, is possible to obtain target...
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Pseudocalculus sign (common bile duct)

The pseudocalculus sign is a term coined to describe a mimic of a distally impacted common bile duct (CBD) stone on ERCP, MRCP and the various forms of cholangiography, including T-tube, CT, intraoperative, and percutaneous 1. It results from the forceful contraction of the choledochal sphincte...
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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...
Article

Rapid ultrasound in shock

The rapid ultrasound in shock (RUSH) protocol is a structured point-of-care ultrasound (POCUS) examination performed at the time of presentation of a shocked patient. It is a more detailed and longer exam than the FAST scan, with the aim to differentiate between hypovolemic, cardiogenic, obstruc...
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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...
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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...
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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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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...
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Scimitar (disambiguation)

The term scimitar, referring to the characteristic shape of the Middle Eastern sword, may refer to the following: scimitar syndrome (lungs) scimitar sign (cystic adventitial disease) scimitar sacrum (bones)
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Segmental arterial mediolysis

Segmental arterial mediolysis (SAM) is an increasingly recognized vascular disease of the middle-aged and elderly and a leading cause of spontanoeus intra-abdominal hemorrhage. It is characterized by fusiform aneurysms, stenoses, dissections and occlusions within splanchnic arterial branches. Im...
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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...
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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...
Article

Seroma

Seromas are collections of serous fluid that usually occur as a complication of surgery, but can also be seen post-trauma. They are commonly seen as an early complication of breast surgery, where a potential space is left. Terminology Seromas are distinct from hematoma as they contain almost n...
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Spinal arteriovenous malformations

Spinal arteriovenous malformations (AVMs) are characterized by arteriovenous shunting with a true nidus. They represent ~25% of spinal vascular malformations.  Epidemiology Different types of spinal AVM (see below) have differing age of presentation, but overall 80% present between the age 20 ...
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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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Spinal interventional procedures

Back pain is a common condition that is often difficult to treat. Lumbar degenerative facet joints, lumbar disc disease and sacroiliac joint pain account for nearly 70% of cases of lower back pain. Unfortunately, as the incidence of degenerative changes in the spine is so high (e.g. disc abnorm...
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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.  ...
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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...
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Stellate ganglion block

A stellate ganglion block can be used to treat a number of conditions by reducing stimulation of the stellate ganglion, which is part of the sympathetic network. The infiltration of local anesthetic/neurolytic around the 1 cm ganglion has been used to treat a variety of disorders. Indications ...
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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...
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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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Supreme intercostal arteries

The supreme intercostal arteries, or superior intercostal arteries, are formed as a direct result of the embryological development of the intersegmental arteries. These arteries are paired structures of the upper thorax which normally form to provide blood flow to the first and second intercosta...
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Surgical positions

There are various classic surgical positions for patients to be placed in for procedures, which have been adopted/repurposed for interventional radiology and some diagnostic procedures: lithotomy position Trendelenburg position reverse Trendelenburg position lateral decubitus position Litho...
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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...
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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...
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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...
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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...
Article

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...
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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 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

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)...
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Tumor embolization

Tumor embolization is a procedure to shut down the blood supply to cancer cells in order to reduce their numbers or cause complete cell death. It can be subdivided into three groups of procedures: bland embolization chemoembolisation embolization with radioactive particles hepatic radioembol...
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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...
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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...
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Ultrasound-guided FNA of the thyroid

Ultrasound-guided fine needle aspiration (FNA) of the thyroid refers to a minimally invasive procedure where in which tissue samples are collected from a thyroid nodule or other suspicious thyroid lesion. It is usually done on a outpatient basis and generally complications are very minimal. Pro...
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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 ...
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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

Upper gastrointestinal bleeding

Upper gastrointestinal bleeding (UGIB) is defined as bleeding proximal to the ligament of Treitz. Epidemiology The incidence of acute upper GI bleeding is ~100 per 100,000 adults per year. Upper GI bleeding is twice as common in men as in women and increases in prevalence with age 5. The demog...
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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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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

Uterine artery embolization: MRI assessment

Uterine artery embolization (UAE) is used as an alternative to hysterectomy in selected patients and MRI assessment is key in allowing not only pre-procedure assessment but also assessing post-procedural outcome.   For a general discussion of the underlying condition refer to the article on ute...
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...
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Varicocele embolization

Varicocele embolization is a minimally invasive method of treating varicoceles by embolizing the testicular vein (internal spermatic veins). Indications symptomatic varicocele infertility/subfertility failed surgical ligation Contraindications Relative contraindications include: intraveno...
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...
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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 ...

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