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 continuously improved upon by countless contributing members. Our dedicated editors oversee each edit for accuracy and style. Find out more about articles.

More than 200 results
Article

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

Periprocedural anticoagulation

Periprocedural anticoagulation planning is essential when planning an interventional procedure so that the best balance between the risk of bleeding and thrombosis can be achieved. The following must be considered in the assessment of periprocedural anticoagulation: bleeding risks associated w...
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Subtalar joint injection (technique)

Subtalar joint injections are most often performed for osteoarthritis with injection into the posterior subtalar joint.  Ultrasound, fluoroscopy and CT guidance can be used. Indications osteoarthritis diagnostic Contraindications Absolute anaphylaxis to contrast/injectates active local/sy...
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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 in its surgical identification and resection. The widespread use of video-assisted thoracic surgery (VATS) and the advance in robotically assisted surgical inter...
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Carbon dioxide angiography

Carbon dioxide (CO2) is an excellent negative contrast agent which has been used for a variety of vascular interventions since the introduction of digital subtraction angiography. Small volumes can be rapidly eliminated by the lungs in a single pass, facilitating safe usage for certain vascular ...
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Lumbar interlaminar epidural injection

Lumbar interlaminar epidural injections are one of some possible spinal epidural injections. For an alternative approach for the same region, please refer to the article on lumbar transforaminal epidural injections.  Indications Typically, epidural injections are performed in patients with rad...
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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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Seldinger technique

The Seldinger technique is the mainstay of vascular and other luminal access in interventional radiology.  Uses digital subtraction angiography insertion of central venous catheters insertion of chest drains insertion of pacemaker leads or implantable cardioverter-defibrillators insertion ...
Article

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....
Article

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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Greater trochanteric bursa injection (technique)

Greater femoral trochanteric bursa injections under ultrasound guidance ensure the injectate is accurately given into the bursa. The greater trochanteric bursa is the largest of the bursae surrounding the proximal femur, with the others including the subgluteus minimus and subgluteus medius burs...
Article

Digital subtraction angiography

Digital subtraction angiography (DSA) is a fluoroscopic technique used extensively in interventional radiology for visualization of blood vessels. Radiopaque structures such as bones are digitally eliminated ("subtracted") from the image, thus allowing for an accurate depiction of the blood vess...
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Billowing phenomenon

Billowing phenomenon refers to the presence of contrast medium on contrast-enhanced CT outside of graft metal struts, due to the specific construction characteristic typical of the AFX® stent-graft (Endologix, Inc., USA), designed to treat abdominal aortic aneurysms. It has a unique internal sca...
Article

Intercostal catheter

Intercostal catheters (ICC), or informally chest tubes, are inserted into the pleural space to drain fluid and/or air. They typically refer to large-bore (10-14 Fr) drains placed under direct vision rather than percutaneous pigtail catheters (6-8 Fr) placed under image guidance. Indication Th...
Article

TIPS evaluation

TIPS evaluation is useful to ensure that a transjugular intrahepatic portosystemic shunt (TIPS) 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...
Article

Splenic artery 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.  I...
Article

Liver biopsy (percutaneous)

Percutaneous liver biopsy, utilizing either ultrasound or CT guidance, allows for an accurate and reliable method of acquiring hepatic tissue for histopathological assessment. It is divided into two types: non-focal or non-targeted liver biopsy (used in the assessment and staging of the parench...
Article

Carotid artery stenosis

Carotid artery stenosis, also known as internal carotid artery stenosis or extracranial carotid artery stenosis, is usually caused by an atherosclerotic process and is one of the major causes of stroke and transient ischemic attack (TIA).  This article refers to stenosis involving the carotid b...
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Inferior vena cava filter

Inferior vena cava filter, or just IVC filter, is an endovascular device that 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. Ind...
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...

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