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Gastrointestinal stents

Gastrointestinal (GI) stents are increasingly used to treat obstruction of the GI tract, most commonly due to malignancy. Types of stent esophageal stent gastric stent duodenal stent enteric stent colorectal stent History and etymology Somewhat surprisingly the word 'stent' is actually a...

Supraclavicular brachial plexus block (ultrasound)

A Supraclavicular brachial plexus block is indicated for establishing sensory and motor blockade of the upper extremity, including the humerus, elbow, forearm, wrist and hand. Indications necessity to provide analgesia of the upper extremity for: abscess incision and drainage elbow dislocat...

Fascia iliaca compartment block (ultrasound)

The fascia iliaca compartment block is a nerve block used to provide anesthesia to the lower extremity commonly in the perioperative period. It is most commonly used for analgesia of the hip, thigh, and knee. It involves the deposition of a local anesthetic beneath the fascia iliaca, targeting t...

O-arm

The O-arm is a movable CT imaging structure developed for intraoperative 3D fluoroscopic imaging. It is utilized during surgery for the identification of bony details in complex procedures such as spinal fixation or microdiscectomy. See also C-arm

Contraceptive implant migration

Contraceptive implant migration is a rare complication of etonogestrel implant insertion. Clinical presentation unable to palpate device in the upper arm chest pain dyspnea non-productive cough menorrhagia irregular vaginal bleeding Pathology Contraceptive implants are most commonly in...

Nephrostogram

Nephrostogram, also known as antegrade pyelogram, is a special x-ray procedure that fluoroscopically evaluates the upper collecting system by introducing water-soluble contrast through the nephrostomy catheter. Indications Nephrostogram can be useful to determine tube position or assess resid...

Superior hypogastric nerve block

Superior hypogastric nerve block is a valuable tool for pain relief in the setting of uterine fibroid embolization. This procedure results in significant ischemic pain, peaking at 6-8 hours and lasting approximately 24 hours, then followed by a lesser degree of post-embolization pain which can l...

Percutaneous mitral commissurotomy

Percutaneous mitral commissurotomy (PMC) also known as percutaneous mitral balloon commissurotomy (PMBC), percutaneous mitral valvotomy (PMV) or percutaneous mitral balloon valvuloplasty (PMBV) is a transcatheter procedure for the management of mitral stenosis. History and etymology Percutaneo...

Transcatheter mitral valve intervention

Transcatheter mitral valve interventions (TMVI) or percutaneous mitral valve interventions are less-invasive, highly technical procedures available for the management of selected patients with mitral valve regurgitation and include several transcatheter mitral valve repair (TMVr) and transcathet...

Cryoablation

Cryoablation refers to the use of thermal energy in the form of very low temperatures to achieve targeted destruction of tumor cells. It is an image-guided technique, currently widely employed in the management of renal 1, hepatic 2 and lung tumors 3. Historically, a rudimental form of cryosurg...

Central vein

A central vein refers to a major vein close to the center of the circulation, i.e. the heart. It originally referred to those large veins in which the distal tip of a catheter could lie for central venous pressure monitoring. To accurately measure the central venous pressure, which is the pressu...

Abdominal paracentesis contraindications (mnemonic)

A mnemonic to remember the contraindications to abdominal paracentesis is: CAPSID Mnemonic C: coagulopathy (INR >2.0) A: abdominal wall cellulitis P: pregnancy S: surgical abdomen (absolute contraindication) / severe thrombocytopenia (platelet count <50 x 103/μL) I: intra-abdominal adhes...

Quadratus femoris injection (technique)

Quadratus femoris injections under image guidance ensure precise delivery of an injectate and ensure the sciatic nerve is avoided during the procedure. CT and ultrasound can be used, with ultrasound becoming more challenging in those with larger body habitus. Indications therapeutic for ischi...

Cephalic arch stenosis

Cephalic arch stenosis is considered one of the commonest cause of dysfunction in a brachiocephalic fistula which involves the cephalic vein in the region of the cephalic arch prior to junction with the axillary vein. Epidemiology Has an average reported prevalance of around 15% in all autogen...

Viscera

The viscera (singular: viscus) refers to all the internal organs within the major cavities of the thorax, abdomen and pelvis. Therefore it does not include organs of the CNS, head and neck or musculoskeletal compartments nor does it encompass non-internal organs (e.g. the skin) 1. Splanchnology...

Paravalvular leak

A paravalvular leak, paravalvular leakage or paravalvular regurgitation are an abnormal flow between the valvular annulus and the prosthetic heart valve and is a common complication after valvular replacement surgery due to inadequate sealing. Epidemiology Paravaluvar leaks are common, with an...

Coronary in-stent restenosis

Coronary in-stent restenosis (ISR) is referred to as an increasing loss of the stented arterial lumen after a percutaneous coronary intervention (PCI) and coronary stent placement which requires revascularization. Terminology However, there are different clinical and angiographic definitions: ...

Coronary stent thrombosis

Coronary stent thrombosis or scaffold thrombosis refers to a recent acute thrombus or occlusion in a coronary segment previously treated with a coronary stent or scaffold. It is a severe complication of percutaneous coronary intervention (PCI) and a major adverse cardiovascular event. Epidemiol...

Coronary stent

Coronary stents or coronary artery stents are expandable tubular medical meshwork devices used for interventional treatment of coronary artery disease and prevention of negative remodeling and vascular recoil, restenosis as well as abrupt vessel occlusion from local coronary artery dissection af...

Winslow pathway

The Winslow pathway is a type of collateral vessel communication which connects the mammary arteries through the internal thoracic arteries to the inferior epigastric arteries and then into the external iliac arteries. It may recanalize in conditions such as aortoiliac occlusive disease.

Fibrin sheath

Fibrin sheaths are a common complication of central venous catheters in which a proteinaceous film encases the outer wall and endhole of the catheter, which can cause catheter malfunction and thrombosis. Clinical presentation Fibrin sheaths present as catheter malfunction, which may include in...

Inguinal hernia repair plug

Inguinal hernia repair plug refers to a nonabsorbable material such as a polypropylene inserted intraoperatively into an inguinal hernial defect. Pathology Usually located anterior to the iliac vessels at the level of the inguinal canal. Size varies with mean long axis diameter 2.6 cm. Unilate...

Trocar technique

The trocar technique is a common technique for surgical procedures and interventional placement of tubes and drainage where instruments, tubes or drains are advanced to the target location through a fixed cannula or hollow tube namely the trocar, which acts as a portal in the process. History ...

No-touch ablation technique

No-touch ablation techniques, using either microwave or radiofrequency to generate heating, refer to approaches whereby the probes are placed at multiple oblique sites tangential and adjacent to the targeted tumor (cf. probe placement centrally within the tumor). Indications For general indic...

Bariatric embolization

Bariatric embolization is an interventional procedure performed with a view to inducing weight-loss in the treatment of obesity. Evidence from clinical trials suggests that the procedure is well tolerated and has a good safety profile. Early studies demonstrate a mild-moderate beneficial effect....

Extra-articular injection

Extra-articular injections occur when the needle tip is not within the targeted joint during joint injections. Terminology Defined by the presence of contrast outside of a joint in fluoroscopic or CT guided procedures, or the lack of direct visualization and resisted flow of intra-articular in...

Knee joint injection (technique)

Knee joint injections under image guidance ensure precise delivery of an injectate into the knee joint. Both fluoroscopy, ultrasound and CT can be used to guide and administer MRI and CT arthrogram injectate, or a steroid containing arthrogram injectate. Indications MRI: retear of repaired m...

Endosaccular flow disruption devices

Endosaccular flow disruption devices, also simply known as flow disruptors, are used for the treatment of either ruptured or unruptured saccular, wide-neck, usually bifurcation as well as side-wall intracranial aneurysms. Their primary function is to stop blood from flowing into the aneurysm, al...

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...

Remasking

Remasking is a post-processing technique used to improve misregistration artifact in digital subtraction angiography, where a frame taken after patient motion is selected as the new mask image for subtraction. In digital subtraction angiography, misregistration (improper image registration) is ...

Pixel shift (reregistration)

Pixel shift or reregistration is a post-processing technique used to improve misregistration artifact in digital subtraction angiography, where two images to be subtracted are spatially realigned with respect to one another, by shifting pixels vertically, horizontally or obliquely. Pixel shift...

Inferior vena cava filter retrieval

Inferior vena cava filter retrieval is an endovascular procedure whereby a previously placed inferior vena cava (IVC) filter is removed. Procedure The procedure is performed under local anesthesia with fluoroscopic guidance. Venous access is usually gained via the internal jugular vein with di...

Superior rectal artery embolization

Superior rectal artery embolization is a minimally invasive endovascular technique which has a role in the management of acute lower gastrointestinal bleeding and has recently re-emerged as a potential option for the treatment of symptomatic hemorrhoidal disease, this article will focus on the l...

Endovascular arteriovenous fistula creation

Endovascular arteriovenous fistula creation is a recently developed minimally invasive alternative for the creation of arteriovenous fistulae for haemodialysis access. Technique Catheter-based technology and image guidance in the form of ultrasound and fluoroscopy is utilized create a side-to-...

Transitional aneurysm

Transitional aneurysms, also referred to as transitional paraclinoid aneurysms, are saccular cerebral aneurysms arising from the clinoid-ophthalmic segment of the internal carotid artery (ICA) and near the distal dural ring with potential risk for subarachnoid hemorrhage. After an anterior turn...

Hip joint injection (technique)

Hip joint injections can be performed with a variety of image guidance, including fluoroscopy and ultrasound, which are used to administer MRI arthrogram injectate, or a steroid containing anesthetic arthrogram injectate. Indications MRI labral injury anesthetic pain / arthropathy, i.e. o...

Percutaneous liver tumor ablation

Percutaneous liver tumor ablation techniques are well-established and effective therapeutic alternatives for the treatment of primary and secondary liver tumors. Hepatocellular carcinoma (HCC) and colorectal oligometastatic disease are the most common indications. There are specific indications ...

Percutaneous lung tumor ablation

Percutaneous lung tumor ablation techniques are an alternative to surgery or stereotactic body radiotherapy (SBRT) for the treatment of certain malignancies. They have specific indications and contraindications, but are mostly limited to small oligonodular and favourably located lesions. They ...

Interventional radiology in practice

Interventional radiology procedures within medical imaging span multiple subspecialties and modalities. This is a collection of articles exploring indications, techniques and practice applications of interventional procedures withing radiology.

Ulnar nerve block (ultrasound-guided)

Ulnar nerve blocks are an approach for delivering anesthesia to the ulnar nerve territory either as a standalone blockade or combined with brachial plexus, radial or median nerve block. Indications burns involving tissue in the ulnar nerve territory rescue analgesia for failed brachial plexus...

Radial nerve block (ultrasound-guided)

Radial nerve blocks are a procedure for delivering anesthesia to the radial nerve territory either as a standalone blockade or in conjunction with a brachial plexus, ulnar or median nerve block. Indications association with median nerve block radial tunnel syndrome forearm and hand surgical ...

Median nerve block (ultrasound-guided)

Median nerve block is a technique used for providing anesthesia to the median nerve territory, it may be performed at the level of the arm, elbow, forearm or the wrist. Indications fracture reductions surgical repair of fractures incision and drainage of cysts and abscesses post-operative a...

Filling defect

A filling defect is a general term used to refer to any abnormality on an imaging study which disrupts the normal opacification (filling) of a cavity or lumen. The opacification maybe physiological, for example, bile in the gallbladder or blood in a dural venous sinus, or maybe due to the instal...

Rotator cuff calcific tendinitis barbotage

Rotator cuff calcific tendonitis can be treated with various techniques including ultrasound-guided barbotage, which is also known as ultrasound-guided needling and lavage. It is often performed in conjunction with a subacromial bursal injection. Alternative treatments include extracorporeal sho...

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...

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)

Splenic biopsy

Percutaneous splenic biopsy, using 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 feared ...

MRI targeted prostate biopsy

MRI targeted prostate biopsy refers to an imaging targeted technique rather than the traditional systematic approach of a prostate biopsy after respective imaging with multiparametric MRI (mpMRI) of the prostate. As a consequence of the recent advances of multiparametric MRI (mpMRI) of the pros...

Double density sign (disambiguation)

The double density sign can refer to several radiological signs: double density sign (left atrial enlargement) double density sign (berry aneurysm) double density sign (osteoid osteoma)

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...

Groshong catheter

Groshong® catheters are a type of central venous catheter, which are placed under direct fluoroscopic visualization in an angiography suite. They can be tunnelled or non-tunnelled and are similar to a Hickman catheter, with the main difference being that Groshong catheters have a three-way valve...

Downhill esophageal varix

Downhill esophageal varices are an uncommon type of esophageal varices associated with superior vena cava (SVC) obstruction. Epidemiology Downhill oesophagal varices are less frequently seen. It is seen in less than 0.5% of routine upper endoscopies. Most common etiology is superior vena obstr...

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...

Microwave ablation

Microwave ablation (MWA) is the application of electromagnetic waves to treat solid tumors. By causing oscillation of polar water molecules, microwaves produce frictional heating and ultimately induce cellular death via coagulation necrosis. This technique has been largely used for the treatment...

Tumor ablation

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

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...

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...

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...

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, whilst high output (>1L/d) are managed with surgical thoracic duct (TD) ligation 2. Thoracic duct em...

Implantable port

Implantable ports, also known as chemoports, totally implantable central venous access ports or Port-A-Caths®, are a type of central venous catheter for patients requiring long-term venous access. They offer the ability to have long-term central venous access with some of the advantages over per...

Radiologically inserted gastrostomy (RIG)

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

Denver shunt

A Denver shunt, or peritoneovenous shunt, is a device used to shunt ascites to the superior vena cava in patients with refractory ascites. The proximal end is located in the peritoneal cavity and the distal end in the superior vena cava, with a subcutaneous course in the anterior chest wall. It...

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...

Heimlich valve

The Heimlich valve, also known as the flutter valve, is a unidirectional valve to ensure that gas/fluid drained from the pleural space cannot flow back in. The Heimlich valve is cheap, easy to use, and does not require clamping unlike 'traditional' thoracostomy drainage tubes. Suction can stil...

Carotid web

Carotid webs, also known as carotid intimal variant fibromuscular dysplasia, are rare vascular pathologies of the internal carotid artery that are an important cause of cryptogenic and recurrent ischemic stroke. Terminology Carotid webs have had many different names in the literature, includin...

Intracranial mycotic aneurysm

Intracranial mycotic aneurysms, or intracranial infectious aneurysms, describe aneurysms arising from infection of the arterial wall of intracranial vessels. See mycotic aneurysm for a general discussion on infectious aneurysms. Epidemiology The epidemiology of intracerebral mycotic aneurysms...

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...

Aortic pseudoaneurysm versus ductus diverticulum

Differentiation of aortic pseudoaneurysm from ductus diverticulum is critical, particularly in the trauma setting. A traumatic aortic pseudoaneurysm is a surgical emergency whereas a ductus diverticulum is a normal anatomic variant. The following are differentiating features: Aortic pseudoaneu...

Labeled imaging anatomy cases

This article lists a series of labeled imaging anatomy cases by body region and modality. Brain CT head: non-contrast axial CT head: non-contrast coronal CT head: non-contrast sagittal CT head: angiogram axial CT head: angiogram coronal CT head: angiogram sagittal CT head: venogram axial...

Digital subtraction angiography

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

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...

Anomalous systemic arterial supply to normal lung

Anomalous systemic arterial supply to normal lung is an anatomical variant in which a portion of the lung (usually a basal segment) is supplied by a systemic vessel without a distinct pulmonary sequestration. Terminology It was traditionally (perhaps inappropriately since not a true sequestrat...

Glenohumeral joint injection (technique)

Glenohumeral joint injections (often referred to as shoulder injections ) are performed as part of a number of therapeutic and imaging procedures using a variety of approaches and modalities. The underlying principles shared by all techniques are to avoid damage to the glenoid labrum, long head ...

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...

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 14 June 1920. He graduated with a...

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...

Hickman catheter

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

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...

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...

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 honor of its inventor. French sizing The French system...

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 ...

Endovascular clot retrieval (ECR)

Endovascular clot retrieval (ECR) is increasingly performed in patients presenting with emergent large vessel occlusion (ELVO), especially those with a large ischemic penumbra that is likely to progress to ischemic stroke. To be successful, careful patient selection and dedicated training and eq...

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...

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 posterior ...

DNB in endovascular and interventional radiology

Diplomate of National Board (DNB) in endovascular and interventional radiology is a postdoctoral super specialty programme in India. eligibility postgraduate degree in radiology (MD/DNB) National Eligibility cum Entrance Test (Super Speciality courses) (NEETSS)/Common Entrance Test (Super S...

DM interventional radiology

DM interventional radiology superspecialty course is a 3-year postgraduate subspecialty training in interventional radiology with the pre-requisites being a primary medical degree and MD radiodiagnosis or DNB radiodiagnosis. Successful completion of the course requires submission of a thesis at ...

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...

Iliac vein occlusion

Iliac vein occlusion can be due to a variety of causes including: iatrogenic neonatal catheters catheter dissection injuries IVC filter insertion dialysis catheters malignancy-related direct tumor invasion radiotherapy enlarged lymph nodes hypercoagulable state prior DVTs May-Thrun...

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...

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. Due to its high solubility rate and rapid diffusibility via the lungs, CO2 is safe for intravascular usage. Physica...

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...

Bähren classification of left varicoceles

Bähren classification of left varicoceles: type 0: no evidence of venous reflux in internal spermatic vein (ISV) type I: single ISV with insufficient or absent valve type II: single ISV with ≥ 2 ostia to renal vein; may be branches to ascending lumbar/retroperitoneal veins IIa: insufficient ...

Multiphase CT angiography in acute ischemic stroke

Multiphase CT angiography is an evolving imaging technique in acute ischemic 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 leptomeninge...