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.

1,009 results found
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Transverse sinus

The transverse sinus is one of the dural venous sinuses and drains the superior sagittal sinus, the occipital sinus and the straight sinus, and empties into the sigmoid sinus which in turn reaches the jugular bulb. The two transverse sinuses arise at the confluence of the three aforementioned s...
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Traumatic aortic injury

Traumatic aortic injury (TAI) is most often caused by blunt trauma (refered to as BTAI) and is best described in terms of injury location, type and and severity: abdominal aortic injury aortic pseudoaneurysm thoracic aortic injury minimal aortic injury See traumatic aortic injury in the exam.
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Traumatic aortic injury in the exam

Getting a film with traumatic aortic injury in the exam is one of the many exam set-pieces that can be prepared for.  This is one of the cases you should look and not speak for 10 seconds as there tends to be a lot of findings on the film of patients with traumatic aortic injury. Description ...
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Tributaries of the inferior vena cava (mnemonic)

A useful mnemonic to remember the tributaries of the inferior vena cava is: I Like To Rise So High Mnemonic I: common iliac veins L: lumbar veins T: right testicular (gonadal) vein R: renal veins S: suprarenal veins H: hepatic veins
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Triple-rule-out CT

Triple-rule-out CT (TRO CT) angiography may be ordered in the setting of acute chest pain to examine the thoracic aorta and the coronary and pulmonary arteries. The protocol helps exclude life-threatening causes of acute chest pain, especially if atypical, or if alternative causes to acute coron...
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True aneurysm

In a true aneurysm, the aneurysm is bound by all three layers of the vessel wall (intima, media and adventitia). The wall may be attenuated. The risk of rupture is proportional to the size of the aneurysm. Pathology Aetiology congenital atherosclerosis hypertension vasculitis hereditar...
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Tulip bulb sign

Tulip bulb sign refers to the characteristic appearance of annuloaortic ectasia as seen on CT angiography. There is symmetric dilatation of the three sinuses of Valsalva, with extension into the ascending aorta and effacement of the sinotubular junction.  It is seen especially in Marfan syndro...
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Tumours of blood vessels

Blood vessel derived tumours may arise from: endothelial cells haemangioma lymphangioma angiosarcoma cells supporting or surrounding blood vessels  glomus tumour of finger haemangiopericytoma Most arise in the soft tissues or viscera. Primary tumours of the large vessels (eg. aorta, IVC)...
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Tumour thrombus

Tumour thrombus is defined as tumour extending into a vessel, typically a vein. It occurs in a wide variety of malignancies. It is vital to distinguish tumour thrombus from "bland" thrombus (free of neoplastic cells) in the setting of neoplasia, as this often impacts staging and treatment approa...
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Tunica (disambiguation)

Tunica is a word used in anatomy to refer to a type of covering.  tunica adventitia (also known as tunica externa) tunica albuginea tunica albuginea (ovary) tunica albuginea (penis) tunica albuginea (testis) tunica intima tunica media tunica vaginalis tunica vaginalis (ovary) tunica va...
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Type I endoleak

Type I endoleaks are a sub group of endoleaks which occur at graft ends, often due to inadequate seal.  Pathology They occur as a result of poor apposition between one of the attachment sites of a stent-graft and the native aortic or iliac artery wall. Blood can leak can occur through this def...
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Type II endoleak

A type II endoleak is a commonest form of endoleak are after an abdominal aortic repair.  Epidemiology They may occur in 10-44% of patients having reparis and can comprise around half of all endoleaks 1. Pathology They may be simple of complex. Simple leak usually occur secondary to backflow...
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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 ...
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Ulnar artery

The ulnar artery is a terminal branch of the brachial artery, arising at the proximal aspect of the forearm. Along with the radial artery, it is one of the main arteries of the forearm.  Summary origin: terminal branch of the brachial artery location: inferior aspect of the cubital fossa sup...
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Ulnar vein

The ulnar vein is one of the two major deep veins of the forearm, along with the radial vein. As is usual in the upper and lower limbs, there are often two veins (venae comitantes) that run on either side of the ulnar artery and anastomose freely with each other. It forms in the hand from the d...
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Ultrasound assessment of carotid arterial atherosclerotic disease

Ultrasound assessment of carotid arterial atherosclerotic disease has become the first choice for carotid artery stenosis screening, permitting the evaluation of both the macroscopic appearance of plaques as well as flow characteristics in the carotid artery. This article focus on internal caro...
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Ultrasound guided peripheral intravenous cannulation

Ultrasound (US) guided peripheral intravenous cannulation (IVC) 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 individua...
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Umbilical arterial aneurysm

An umbilical arterial aneurysm (UAA) is an extremely rare but potentially lethal vascular anomaly which is usually detected in utero.  Pathology Location If tends to favour the placental end of the umbilical artery in the cord. Associations Concurrent associated anomalies are thought to be ...
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Umbilical arterial catheters

Umbilical arterial catheters are used in neonatal care and need to be carefully assessed on all neonatal films.  Position The catheter should pass through the umbilicus, travel inferiorly through the umbilical artery, then in the anterior division of the internal iliac artery, into the common ...
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Umbilical artery

The umbilical artery gives rise to both a nonfunctional remnant of the fetal circulation, and an active vessel giving supply to the bladder. In the adult the obliterated area of the vessel is identifiable as the medial umbilical ligament and the patent segment is the superior vesical artery. Su...
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Umbilical vein varix

Umbilical vein varix (UVV) refers to a focal dilatation of the umbilical vein. Pathology Location It tends to favour the intra-abdominal portion of the cord (typically between the abdominal wall and the liver) which is then termed a fetal intra-abdominal umbilical vein varix (FIUVV) or the in...
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Umbilical venous catheters

Umbilical venous catheters are commonly used in the neonatal period for vascular access and should be carefully assessed for position on all neonatal films.  Position An umbilical venous catheter generally passes directly superiorly and remains relatively anterior in the abdomen. It passes thr...
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Unfolded aorta

The term unfolded aorta refers to the widened and 'opened up' appearance of the aortic arch on a frontal chest radiograph. It is one of the more common causes for apparent mediastinal widening and is seen with increasing age. It occurs due to the discrepancy in the growth of the ascending aorta...
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Unilateral pulmonary artery atresia

Unilateral pulmonary artery atresia (UPAA) or unilateral absence of the pulmonary artery (UAPA) is a variant of pulmonary artery atresia.  Epidemiology The estimated prevalence is around 1 in 200,000 young adults. The reported frequency on the right side is slightly greater for some reason 10....
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Unilateral pulmonary vein atresia

Unilateral pulmonary vein atresia is a type of pulmonary vein atresia. Clinical presentation The condition usually present in infancy or childhood with recurrent episodes of pneumonia and/or haemoptysis. Presentation in adulthood does occur but is uncommon. Pathology It results from failure ...
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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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Upper limb anatomy

Upper limb anatomy encompasses the anatomy of the shoulder, arm, elbow, forearm, wrist and hand. This anatomy section promotes the use of the Terminologia Anatomica, the global standard for correct gross anatomical nomenclature. 
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Uterine arteriovenous malformation

Uterine arteriovenous malformations (UAVM) result from formation of multiple arteriovenous fistulous communications within the uterus without an intervening capillary network. Clinical presentation Presentation can vary. UAVMs can cause life-threatening massive bleeding in young women. Bleedin...
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Uterine artery

The uterine artery is seen bilaterally and is a branch of the anterior division of the internal iliac artery. Gross anatomy Course It runs medially in the pelvis, within the base of the broad ligament, to the outer surface of the uterus. From lateral to medial it has a descending, transverse ...
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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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Uterine artery embolisation: MRI assessment

Uterine artery embolisation (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...
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Uterine artery flow notching

Uterine artery flow notching refers to phenomenon observed in uterine arterial Doppler ultrasound assessment. Pathology Associations The presence of notching after 22 weeks is associated with several other conditions including adverse pregnancy outcomes. These include pregnancy induced hyper...
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Uterine artery pseudoaneurysm

Uterine artery pseudoaneurysm (UAP) is a rare cause of secondary postpartum haemorrhage.  Clinical presentation UAP usually presents as delayed (secondary) postpartum haemorrhage, that is per vaginal bleeding which occurs more than 24 hours and up to 6 weeks postpartum. However, some reported ...
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Vaginal artery

The vaginal artery is a branch of the anterior division of the internal iliac artery, and should not to be mistaken with the vaginal branch of the uterine artery. It is often considered to be a homolog of the inferior vesical artery, which is present only in males. Summary origin: anterior div...
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Variant anatomy of the aortic arch

Variant anatomy of the aortic arch occurs when there is failure of normal aortic development. It results in a number of heterogenous anomalies of the aorta and its branch vessels. Gross anatomy Normally, the aorta ascends in the superior mediastinum to the level of the sternal notch before arc...
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Variant hepatic arterial anatomy

Variation in hepatic arterial anatomy is seen in 40-45% of people. Classic branching of the common hepatic artery from the coeliac artery, and the proper hepatic artery into right and left hepatic arteries to supply the entire liver, is seen in 55-60% of the population.  In general, the common ...
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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 general male population and ~40% of subfertile a...
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Varicocele embolisation

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

Varicocele grading on colour Doppler can be done variably. The most elaborate and widely-accepted grading was given by Sarteschi, as below.  For a general discussion of this condition refer to the article: varicocoele. Evaluation baseline greyscale study in supine position and measure the dia...
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Varicose veins

Varicose veins are dilated tortuous superficially located venous channels that accompany the superficial veins of the upper or lower limbs. Epidemiology Varicose veins are more common in women than men and are more common in the lower limb than in the upper limb 5. Risk factors include: pregn...
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Vascular anatomical variants

Vascular anatomical variants are common. Aorta variants Thoracic aorta Ascending aorta Aortic arch Descending aorta Abdominal SVC & IVC - variants Intracranial arteries - variants
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Vascular compression disorders

Vascular compression disorders are numerous and can be divided into those cases where a vascular structure is the "compress-er" or the "compress-ee" . Some conditions fall into both categories, where one vessel compresses another.  Compression of a vascular structure  Eagle syndrome thoracic ...
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Vascular Ehlers Danlos syndrome

Vascular Ehlers-Danlos syndrome (EDS) or type IV Ehlers-Danlos syndrome (EDS 4) is the most malignant form of Ehlers-Danlos syndrome. This form is often accompanied by neurovascular complications secondary to vessel dissections and/or aneurysms. Epidemiology Vascular EDS represents about 4% of...
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Vascular malformations and tumours

Vascular malformations and tumours are a heterogeneous group of lesions that may affect the arterial, capillary, venous or lymphatic system or any combination thereof. They encompass a bewildering range of lesions,  syndromes, and masses ranging from the relatively common (e.g. infantile haemang...
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Vascular pathology

Vascular pathologies are common and include: arteriosclerosis hypertension fibromuscular dysplasia inherited disorders of the vessel wall aneurysms dissection thromboembolism vasculitis vasospasm vascular trauma intimal hyperplasia tumours of blood vessels congenital vascular anomal...
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Vascular rings and slings

Vascular rings and slings refer to the congenital vascular encirclement of the oesophagus and/or trachea by anomalous/aberrant vessels.  Epidemiology Vascular rings are rare, occurring in <1% of patients 1. No gender or ethnic predispositions have been identified 3.  Clinical presentation Ma...
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Vascular syndromes

The are numerous vascular syndromes that can occur in the body. There include Syndromes principally involving the vascular system Budd-Chiari syndrome coeliac artery compression syndrome hereditary haemorrhagic telangiectasia (Osler-Weber-Rendu syndrome) hypothenar hammer syndrome Kasabach...
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Vascular trauma

Great vessels thoracic aortic injury Solid organ renal pedicle injury
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Vasculitis

Vasculitis describes generalised inflammation of vessels. Vasculitides carry a broad range of clinical presentations and as a whole can involve almost any organ system. Pathology Some vasculitides are due to direct vessel injury from an infectious agent. However a large proportion show evidenc...
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Vein of Galen

The vein of Galen, also known as the great cerebral vein or great vein of Galen, is a short trunk formed by the union of the two internal cerebral veins and basal veins of Rosenthal. It lies in the quadrigeminal cistern. It curves backward and upward around the posterior border of the splenium o...
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Vein of Galen aneurysmal malformation

Vein of Galen aneurysmal malformations (VGAMs), probably better termed as median prosencephalic arteriovenous fistulas, are uncommon intracranial anomalies that tend to present dramatically during early childhood with features of a left-to-right shunt and high-output cardiac failure. Epidemiolo...
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Vein of Labbé

The vein of Labbé, also known as inferior anastomotic vein, is part of the superficial venous system of the brain.  The vein of Labbé is the largest channel that crosses the temporal lobe between the Sylvian fissure and the transverse sinus and connects the superficial middle cerebral vein to t...
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Vein of Marshall

The vein of Marshall, oblique vein of Marshall or the oblique vein of the left atrium is a small vein that descends on and drains the posterior wall of the left atrium. It drains directly into the coronary sinus at the same end as the great cardiac vein, marking the origin of the sinus. It repr...
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Veins of Sappey

Veins of Sappey are small veins around the falciform ligament that drain the venous blood from the anterior part of the abdominal wall directly into the liver. This flow dilutes the portal perfusion at these sites, causing hepatic pseudolesions. Gross anatomy The superior vein of Sappey drains...
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Vena cava filter

Vena cava 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. Indications contraindication to...
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Vena caval foramen

The vena caval foramen is one of the three major apertures in the diaphragm. It is the highest of the three and situated at the level of T8-9. It is quadrilateral and placed at the junction of the right and middle leaflets of the central tendon. It transmits several structures between the thora...
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Venae cordis minimae

The venae cordis minimae (smallest cardiac veins or thebesian veins) are a small group of valveless myocardial coronary veins within the walls of each of the 4 cardiac chambers that drain venous blood directly into each of the respective chambers. They are most frequent in the right atrium and t...
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Venous drainage of the thoracic wall

The venous drainage of the thoracic wall drains deoxygenated venous blood from the peripheries of the thoracic cage back into systemic circulation. Gross anatomy Anterior thoracic wall Anterior intercostal veins The anterior intercostal veins originate from the intercostal space just inferio...
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Venous thromboembolism

Venous thromboembolism covers a wide spectrum of diseases. Individual conditions and complicating condition include: deep vein thrombosis (DVT) pulmonary embolism (PE) dural venous sinus thrombosis Lemierre's syndrome tumour thrombus
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Vertebral artery

The vertebral arteries (VA) are paired arteries, each arising from the respective subclavian artery and ascending in the neck to supply the posterior fossa and occipital lobes, as well as provide segmental vertebral and spinal column blood supply. Summary origin: branches off the 1st part of t...
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Vertebral artery dissection

Vertebral artery dissection, like arterial dissection elsewhere, is a result of blood entering the media through a tear in the intima. It is potentially lethal and can be difficult to diagnose clinically and radiologically. Epidemiology Vertebral artery dissections have an incidence of 1-5 per...
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Vertebral artery ectasia

Vertebral artery ectasia refers to an abnormal dilatation of the vertebral artery. It is also known as a dolichoarterial loop (of Danziger). Clinical presentation Symptoms occur due to radicular compression or pathologic fracture (rare) from extensive bone erosion. Generally, patients present ...
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Vertebral artery thrombosis

Vertebral artery thrombosis results in complete or partial occlusion of the vertebral artery and alteration of blood flow to the posterior cerebral circulation. Ischaemia or infarction to structures supplied by these arteries may result in a range of symptoms. brainstem cerebellum occipital l...
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Vertebral venous plexus

The vertebral venous plexus is a highly anastomotic network of valveless veins running along the entire length of the vertebral column from the foramen magnum to the sacral hiatus. Gross anatomy The vertebral venous plexus is comprised of three interconnected divisions: internal vertebral ven...
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Vestibule (disambiguation)

A vestibule is an anatomical term and refers to a small cavity at the proximal end of a tube. vestibule (aorta) vestibule (ear) vestibule (larynx) vestibule (mouth) vestibule (nose) vestibule (oesophagus) vestibule (vagina) History and etymology Vestibule derives ultimately from the Lat...
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Vidian artery

There are two arteries passing through Vidian canal from the pterygopalatine fossa to the petrous portion of the ICA. One is a branch of the internal maxillary artery (itself a branch of the ECA) and the other is from the C2 segment of the ICA. It therefore forms one of the ICA to ECA anastamoses.
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Virchow triad

Virchow triad refers to the factors which can promote thrombosis, and are useful when thinking about the possible causes in a particular situation. They are: hypercoagulability primary thrombophilia factor V Laden deficiency  protein S deficiency  protein C deficiency  antithrombin III def...
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Visceral artery aneurysm

Visceral artery aneurysms are abnormal focal dilatations of arteries supplying abdominal organs. Visceral artery aneurysms include both true aneurysms and pseudoaneurysms. Owing to different clinical manifestations and a unique, specific, pathology, renal artery aneurysms are discussed separate...
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Wells criteria for deep venous thrombosis

Wells criteria for deep venous thrombosis is a risk stratification score and clinical decision rule to estimate the pretest probability for acute deep venous thrombosis (DVT). It is intended to be combined with noninvasive diagnostic tests (e.g. ultrasound or D-dimer) for suspected cases. Crite...
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Westermark sign

Westermark sign is a sign of pulmonary embolus seen on chest radiographs. It is one of several described signs of pulmonary embolus on chest radiographs. Pathology The theory behind the sign is either obstruction of the pulmonary artery or distal vasoconstriction in hypoxic lung 3. In one stu...
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WFNS grading system

The WFNS (World Federation of Neurosurgical Societies) grading system uses the Glasgow Coma Scale and presence of focal neurological deficits to grade the severity of subarachnoid haemorrhage. This grading system was proposed in 1988, and this is one of the accepted systems (although not conside...
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White coat effect

The white coat effect (WCE), not to be confused with white coat hypertension, is a measure of change that is commonly defined as the difference between in-clinic and out-of-clinic blood pressure readings 1,2.  Alternatively, the white coat effect can be defined as the increase in the arterial b...
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White coat hypertension

White coat hypertension (abbreviated alternatively as WCH or WCHT), not to be confused with the white coat effect (WCE), is commonly defined as typical in-clinic blood pressure (BP) measurements of 140/90 mm Hg or more in the presence of multiple daytime out-of-clinic home or ambulatory BP readi...
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Williams syndrome

Williams syndrome (WS) is characterised by some or all or the following features: craniofacial dysmorphism (e.g. elfin facies) oral abnormalities short stature (50% of cases) mild to moderate mental retardation supravalvular aortic stenosis 2 pulmonary artery stenosis 3 renal insufficienc...
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Windsock sign (aortic dissection)

The windsock sign refers to appearances seen in type A thoracic aortic dissections on contrast CT. It results from intimo-intimal intussusception between the true and false dissected lumens of the thoracic aorta. The altering density of contrast between the dissection lumens which taper distally...
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Wyburn-Mason syndrome

Wyburn-Mason syndrome (also known as Bonnet-Dechaume-Blanc syndrome) is a rare, nonhereditary neurocutaneous disorder that typically presents with unilateral vascular malformations that primarily involve the brain, orbits and facial structures. It is currently classified as a craniofacial arteri...
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Yasargil classification of vein of Galen aneurysmal malformations

The Yasargil classification is one of the two common systems for classifying vein of Galen malformations that is currently in use at the time of writing (mid 2016).  Classification type I: small pure cisternal fistula between the vein of Galen (voG) and either the pericallosal arteries (anteri...
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Yellow nail syndrome

The yellow nail syndrome (YNS) is rare disorder principally affecting lymphatic system It is characterised by  nail discolouration: yellow slow growing dystrophic nails peripheral / primary lymphoedema pulmonary manifestations exudative pleural effusions (least common manifestation) bronch...
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Yin-yang sign

The yin-yang sign (also known as Pepsi sign) is a radiological sign described in both true and false aneurysms on various imaging modalities.  Radiographic features Doppler sonography The yin-yang sign indicates bidirectional flow due to swirling of blood within the (true or false) aneurysm. ...

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