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.

48 results found
Article

Acute aortic syndrome

Acute aortic syndrome (AAS) describes the presentation of patients with one of a number of life threatening aortic pathologies that give rise to aortic symptoms. The spectrum of these aortic emergencies include: aortic dissection aortic intramural haematoma penetrating atherosclerotic ulcer ...
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Acute basilar artery occlusion

Acute occlusion of the basilar artery may cause brainstem or thalamic ischaemia or infarction. It is a true neuro-interventional emergency and, if not treated early, brainstem infarction results in rapid deterioration in the level of consciousness and ultimately death. Epidemiology Occlusions ...
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AFP elevation

Human alpha fetoprotein (AFP) elevation may occur in a vast number of conditions: liver tumours (hepatocellular carcinoma, hepatoblastoma) <10 ng/ml is within normal limits >20 ng/ml is above normal limits but has low specificity for tumor since it may occur in a setting of diffuse liver inju...
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Anterior inferior cerebellar artery (AICA) infarct

Anterior inferior cerebellar artery (AICA) territory infarcts are much less common than posterior inferior cerebellar artery (PICA) infarcts. Epidemiology AICA territory infarcts are rare, comprising ~1% of ischaemic cerebellar strokes 2.  Clinical presentation AICA stroke syndrome presents ...
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Artery of Percheron territory infarct

Artery of Percheron territory infarct is rare, on account of the relative rarity of the artery of Percheron, and presents with a variety of signs and symptoms collectively termed the paramedian thalamic syndrome. It is a type of posterior circulation infarction. On imaging, it is classically ch...
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Ascending aorta dilatation

Dilatation of the ascending aorta is a common finding in the elderly but unusual in younger patients. Pathology In adults, an ascending aortic diameter greater than 4 cm is considered to indicate dilatation 4. Aneurysmal dilatation is considered when the ascending aortic diameter reaches or ex...
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Carotid artery stenosis

Carotid artery stenosis also referred as 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) 1.  This article refers to stenosis involving carotid bulb and the proximal segment of inte...
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Carotid pacemaker

Carotid pacemaker, also known as implantable carotid sinus stimulators, is a device that delivers activation energy through the carotid leads and the leads conduct activation energy to the carotid baroreceptors. This is sometimes offered for drug-resistant hypertension. The baroreceptors send si...
Article

Causes of a small aorta

Causes of a small aorta include: Williams syndrome Takayasu arteritis giant cell arteritis neurofibromatosis midaortic syndrome small aorta syndrome idiopathic
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Causes of ascending aorta calcification

There are relatively few causes of calcification of the ascending aorta 1-3: atherosclerosis (this usually spares the ascending aorta) aortitis syphilis Takayasu arteritis idiopathic
Article

Cerebral vascular malformations

Vascular malformations of the central nervous system can be divided, as they can elsewhere, into high and low flow malformations. High flow arteriovenous malformation (AVM) cerebral AVM (pial/parenchymal AVM) cerebral proliferative angiopathy dural arteriovenous fistula (DAVF) pial arteri...
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COL4A1-related disorders

COL4A1-related disorders are a group of autosomal dominant disorders caused by a mutation in the COL4A1 gene. Epidemiology The exact prevalence is unknown, but the group of disorders is considered to be under-recognised, especially asymptomatic variants 1. Clinical presentation The clinical ...
Article

Coronary artery bypass graft

A coronary artery bypass graft (CABG or CAG) is placed during a surgical procedure to increase blood flow to the myocardium due to coronary stenoses, usually caused by coronary artery disease. Arteries or veins can be grafted during this procedure. Long term outcome of coronary artery bypass gr...
Article

Differential diagnosis of vascular calcification

The differential diagnosis of vascular calcification is very wide with many common and uncommon conditions. Differential diagnosis Common aneurysm atherosclerosis end-stage renal failure 3 hemangioma; arteriovenous malformation hyperparathyroidism, primary or secondary (renal osteodystrop...
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Endoleak

Endoleaks are characterised by persistent blood flow within the aneurysm sac following endovascular aneurysm repair (EVAR). Normally the aortic stent-graft used for EVAR excludes the aneurysm from the circulation by providing a conduit for blood to bypass the sac. Epidemiology An endoleak is a...
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Enlarged azygos vein

An enlarged/dilated azygos vein may result from a number of physiological as well as pathological causes. The enlarged azygos vein may be seen as a widened right paratracheal/paraspinal stripe on a frontal chest radiograph. Causes for dilatation There are a number of physiological causes for e...
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Enlarged pulmonary trunk on chest radiography (differential)

The differential of an enlarged pulmonary trunk/main pulmonary artery on chest radiography includes:  normal may appear prominent in young patients especially women projectional rotation lordotic view rotation of the heart pectus excavatum left lower lobe collapse pulmonary arterial hyp...
Article

Haemoptysis

Haemoptysis refers to coughing out blood. Generally, it appears bright red in colour as opposed to blood from gastrointestinal tract which appears dark red. It is considered an alarming sign of a serious underlying aetiology. Terminology Massive haemoptysis is referred to as expectoration of >...
Article

Hepatic lymphangioma

A hepatic lymphangioma is a rare benign condition that corresponds to focally dilated lymphatic channels in the liver.  Clinical presentation Most cases are asymptomatic. Pathology A lymphangioma is a benign lesion that can occur at almost any location in the body. Hepatic involvement is les...
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Hyper-reninaemic hypertension (differential)

Hyper-reninaemic hypertension may have many causes including: renal artery stenosis renal secreting tumour, e.g. renal cell carcinoma, reninoma renal compression: large renal mass, subcapsular haemorrhage (Page kidney)
Article

Iliac vein occlusion

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

Innominate artery compression syndrome

Innominate artery compression syndrome, also known as brachiocephalic artery compression syndrome, is a rare cause of tracheal stenosis that occurs in the paediatric population. Pathology It can only occur in the presence of an aberrantly positioned thymus that forces the aortic arch or innomi...
Article

Left paramediastinal catheter position (differential)

When a central venous catheter that is supposed to project over the superior vena cava is abnormally located to the left of the mediastinum a limited differential of left paramediastinal catheter position should be considered 1: located within the vein left sided superior vena cava left inter...
Article

Lower gastrointestinal bleeding (differential)

Lower gastrointestinal bleeding usually occurs distal to the ligament of Treitz. Clinical presentation Presents with melaena, haematochezia or, if subclinical slow bleeding, chronic anaemia. Causes diverticular disease enterocolitis infective Crohn’s disease ulcerative colitis ischaemic...
Article

Medical devices in the neck

Medical devices in the neck are regularly observed by radiologists on plain film and CT reporting. They include devices which pass through the neck onto the chest and stomach. Vascular access devices dialysis catheters peripherally inserted central catheters (PICC) central venous catheters ...
Article

Moyamoya syndrome

Moyamoya syndrome, also termed the moyamoya pattern or phenomenon, is due to numerous conditions that can cause arterial occlusion of the circle of Willis, with resultant collaterals, and appearances reminiscent of moyamoya disease. These conditions include 1-4 : vessel wall abnormalities athe...
Article

Oxalosis

Oxalosis results in supersaturation of calcium oxalate in the urine (hyperoxaluria), which in turn results in nephrolithiasis and cortical nephrocalcinosis.  This article focus on the secondary oxalosis, please refer to primary oxalosis for a specific discussion on this entity.  Pathology Cal...
Article

Partial anomalous pulmonary venous return

Partial anomalous pulmonary venous return (PAPVR), also known as partial anomalous pulmonary venous connection (PAPVC), is a rare congenital cardiovascular condition in which some of the pulmonary veins, but not all, drain into the systemic circulation rather than in the left atrium. Clinical p...
Article

Pericardial calcification

Pericardial calcification (PC) usually occurs in patients with a history of pericarditis.  Pathology Causes uraemia previous trauma or prior pericarditis later sequelae of rheumatic heart disease malignant pericardial involvement (e.g. mediastinal teratoma) On chest radiography, location ...
Article

Phleboliths

Phleboliths are literally "vein stones", and represent calcification within venous structures. They are particularly common in the pelvis where they may mimic ureteric calculi, and are also encountered frequently in venous malformations. There is an association with Maffucci syndrome.  Radiogra...
Article

Polymyalgia rheumatica

Polymyalgia rheumatica (PMR) is a common inflammatory condition typically affecting elderly people. It is a multisystem disorder but usually affects the musculoskeletal system. It can manifest in various ways, which are best discussed in the separate articles below: polymyalgia rheumatica: mus...
Article

Portal venous gas

Portal venous gas is the accumulation of gas in the portal vein and its branches. It needs to be distinguished from pneumobilia, although this is usually not too problematic, when associated findings are taken into account along with the pattern of gas (i.e. peripheral in portal venous gas, cent...
Article

Pulmonary arterial calcification

Pulmonary arterial calcification is the phenomenon which is usually seen in the setting of advanced pulmonary hypertension. It can however be uncommonly present in those without pulmonary hypertension. Pathology The general mechanism in the vast majority is thought to be from high end pulmonar...
Article

Pulmonary hypertension (differential)

Pulmonary hypertension has many causes, and these can be divided in many ways. A simple and systematic approach is to proceed along the cardiopulmonary pulmonary circulation, as causes are found at each site (for a more official classification system see 2003 third world symposium on pulmonary a...
Article

Pulmonary infarction

Pulmonary infarction is most commonly caused by pulmonary embolism (PE) in combination with chronic left heart failure. Epidemiology The demographics of affected patients are older than those of patients with 'simple' pulmonary embolism (PE) as young patients with no comorbidities are usually ...
Article

Renal artery dissection

Renal artery dissection may occur as a result of the following processes 1: aortic dissection extending to involve the renal artery iatrogenic (e.g. catheterisation) trauma atherosclerosis fibromuscular dysplasia
Article

Renal artery stenosis

Renal artery stenosis (RAS) refers to a narrowing of a renal artery. When the process occurs slowly, it leads to secondary hypertension. Acute renal artery stenosis does not lead to hypersecretion of renin. Pathology When the stenosis occurs slowly, collateral vessels form and supply the kidne...
Article

Renal vein varices

Renal vein varices develop for various reasons and are usually asymptomatic. Clinical presentation Renal vein varices are usually asymptomatic. Some patients may present with flank pain and/or haematuria. Pathology Aetiology chronic renal vein thrombosis nutcracker syndrome retroaortic ...
Article

Renovascular hypertension

Renovascular hypertension (RVH) is a type of secondary hypertension, where high blood pressure develops secondary to renal artery disease.  Epidemiology Approximately 2.5% (range 0.5-5%) of hypertensive patients will have RVH as a cause 2,3.  Pathology Aetiology There are a number of condit...
Article

Spinal vascular malformations

Spinal vascular malformations (SVM) are rare but knowledge of them is important as if undiagnosed and untreated they can lead to serious complications.  Pathology There are two main types of SVMs 1,2: spinal arteriovenous fistula (AVF): 70% of SVMs pial: small, large, or giant dural AVF (DA...
Article

Superficial thrombophlebitis

Superficial thrombophlebitis, also called superficial venous thrombosis (SVT), is a pathological condition characterized by the presence of a thrombus in the lumen of a superficial vein, accompanied by inflammatory reaction of adjacent tissues. Terminology Some authors however reserve the term...
Article

Tear drop sign of the superior mesenteric vein

Tear drop sign of the superior mesenteric vein (SMV) is one of the important signs in the staging of pancreatic adenocarcinoma. Its importance lies in its diagnosis as well as prognostic significance. This sign is used in assessing the resectability of pancreatic cancer. Radiographic appearance...
Article

Thoracic aortic dilatation (differential)

There are a number of causes and mimics of thoracic aortic dilatation. Differential diagnosis senile ectasia hypertension post-stenotic dilatation, e.g. bicuspid aortic valve thoracic aortic aneurysm atherosclerosis (usually descending thoracic aorta) collagen disorders Marfan syndrome ...
Article

Thoracic aortic stenosis (differential)

The differential for thoracic aortic stenosis includes: atherosclerosis aortitis (especially Takayasu arteritis) radiation coarctation pseudocoarctation Williams syndrome: supravalvular aortic stenosis congenital rubella syndrome: supravalvular aortic stenosis
Article

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...
Article

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
Article

Visceral artery aneurysms

Visceral artery aneurysms (VAA) are abnormal focal dilatations of arteries supplying an organ in the abdomen. VAAs include both true and pseudoaneurysms. With different clinical manifestations and a more characteristic pathology, the renal artery aneurysms are discussed separately.  Epidemiolo...
Article

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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