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.

31 results found
Article

Inferior vena caval contrast reflux

Reflux of contrast into inferior vena cava can be common findings seen on CT. It is considered a specific but insensitive sign of right-sided heart disease / right heart dysfunction at low contrast injection rates although the usefulness decreases with high injection rates. Conditions associate...
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Intrahepatic arteriovenous shunt

Intrahepatic arteriovenous shunts, also referred to as intrahepatic arteriovenous malformations (AVMs) or hepatic arteriosystemic venous shunts, represent a spectrum of abnormal communications between the hepatic arterial system and the hepatic veins.  Please note that arterioportal shunts, whi...
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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...
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Spinal vascular malformations

Spinal vascular malformations are rare but knowledge of them is important as if undiagnosed and untreated they can lead to serious complications. The main types are arteriovenous fistulae, arteriovenous malformations, cavernous malformations, and capillary telangiectasia. Pathology Classificat...
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Valsalva maneuver

The Valsalva maneuver is the forced expiration of air against a closed airway, resulting in increased intra-abdominal, intrathoracic, and pharyngeal pressure. It can be performed against a closed glottis or by one closing the mouth and pinching the nose while forcibly exhaling. It is commonly u...
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Medical devices in the head and neck

Medical devices in the head and neck are regularly observed by radiologists on plain film, CT and MRI reporting. They include devices which pass through the neck into the chest and stomach or ascend to/into the head. Vascular access devices dialysis catheters peripherally inserted central cat...
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Pulmonary arterial calcification

Pulmonary arterial calcification is a 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 pulmonary ...
Article

Visceral artery aneurysm

Visceral artery aneurysms are abnormal focal dilatations of splanchnic 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 discuss...
Article

Hemoptysis

Hemoptysis (plural: hemoptyses) refers to coughing up of blood. Generally, it appears bright red in color as opposed to blood from the gastrointestinal tract which appears dark red. It is considered an alarming sign of a serious underlying etiology. Terminology Massive hemoptysis is referred t...
Article

Small aorta (differential)

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

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...
Article

Pulmonary vasculitis

Pulmonary vasculitis refers to vasculitides that affect the lung or pulmonary vessels. If this definition is used, a large group of conditions can fall into this category. The respiratory system may be potentially involved in all systemic vasculitides, although to a variable degree. Pathology ...
Article

Renal vein varices

Renal vein varices (singular: varix) 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 hematuria. Pathology Etiology chronic renal vein thrombosis nutcracker syndrom...
Article

Medical devices in the thorax

Medical devices in the thorax are regularly observed by radiologists when reviewing radiographs and CT scans. Extrathoracic devices tubing, clamps, syringes, scissors, lying on or under the patient rubber sheets, foam mattresses, clothing, hair braids, nipple piercings, etc. may also be visib...
Article

Carotid pacemaker

Carotid pacemakers, also known as implantable carotid sinus stimulators, are devices that deliver activation energy, via carotid leads, to the carotid baroreceptors. This is sometimes offered for drug-resistant hypertension. The baroreceptors send signals to the brain and the signals are interpr...
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

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...
Article

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. Terminology Spelling it "azygous" when referring to the vein is incorr...
Article

Left paramediastinal catheter position (differential)

When a central venous catheter that is supposed to terminate in the superior vena cava or right atrium is abnormally located to the left of the mediastinum and below the level of the brachiocephalic vein, a limited differential of left paramediastinal catheter position should be considered 1: l...
Article

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 See also porcelain aorta
Article

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

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

Lower gastrointestinal bleeding (differential)

Lower gastrointestinal bleeding usually occurs distal to the ligament of Treitz, and has a wide differential diagnosis: diverticular disease enterocolitis infective Crohn’s disease ulcerative colitis ischemic colitis vascular malformation vascular ectasia angiodysplasia arteriovenous m...
Article

Upper gastrointestinal bleeding (differential)

An upper gastrointestinal bleed usually refers to bleeding proximal to the ligament of Treitz. Pathology Aetiolology peptic ulcer gastritis esophagitis duodenitis Mallory-Weiss tear varices tumor vascular abnormality vascular ectasia angiodysplasia Dieulafoy lesion vascular malform...
Article

Hyperreninaemic hypertension (differential)

Hyperreninaemic hypertension may have many causes including: renal artery stenosis renal secreting tumor, e.g. renal cell carcinoma, reninoma renal compression: large renal mass, subcapsular hemorrhage (Page kidney)
Article

Renal artery stenosis

Renal artery stenosis (RAS) (plural: stenoses) 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 a...
Article

Thoracic aortic stenosis (differential)

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

Thoracic aortic dilatation (differential)

There is a broad differential for 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 Ehlers-Da...
Article

Hypervascular liver lesions

Hypervascular liver lesions are findings that enhance more or similarly to the background hepatic parenchyma in the late arterial phase, on contrast-enhanced CT or MRI. Differential diagnosis Primary lesions hepatocellular carcinoma (HCC) most common hypervascular primary liver malignancy e...
Article

Cerebrovascular malformations

Cerebrovascular malformations are vascular malformations related to the vessels that supply the brain and other cranial structures. Classification Over the years, cerebrovascular malformations have been classified in a variety of ways by different authors. Over the years cerebral vascular mal...
Article

Venous thromboembolism

Venous thromboembolism covers a wide spectrum of diseases. Individual conditions and complicating condition include: head and neck cerebral vein thrombosis dural venous sinus thrombosis cavernous sinus thrombosis deep cerebral vein thrombosis cortical vein thrombosis superior ophthalmic v...

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