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.
16,925 results
Article
Weigert-Meyer law
The Weigert-Meyer law describes the relationship of the upper and lower renal moieties in duplicated collecting systems to their drainage inferiorly.
Weigert-Meyer law
With duplex kidney and complete ureteral duplication, the upper renal and lower renal moieties are drained by separate ureters...
Article
Cassette
Cassettes are rigid holders used in conventional and computed radiography (CR) for the screen film system and imaging plate respectively.
The back side of the cassette has rubber or felt for adequate contact between the screen film system or with the imaging plate. The front of the cassette is...
Article
Cerebral edema
Cerebral edema refers to a number of interconnected processes which result in abnormal shifts of water across various compartments of the brain parenchyma. It is observed in the majority of injuries involving the central nervous system 5.
It has traditionally been broadly divided into vasogenic...
Article
AAST injury scoring scales
The American Association for the Surgery of Trauma (AAST) injury scoring scales are the most widely accepted and used system of classifying and categorizing traumatic injuries. Injury grade reflects severity, guides management, and aids in prognosis. 32 different injury scores are available (c. ...
Article
Pneumoperitoneum
Pneumoperitoneum (aeroperitoneum is a rare synonym 12) describes gas within the peritoneal cavity, often due to critical illness. There are numerous causes and several mimics.
Pathology
The most common cause of pneumoperitoneum is the disruption of the wall of a hollow viscus. In children, the...
Article
Rigler sign (bowel)
The Rigler sign, also known as the double-wall sign, is a sign of pneumoperitoneum seen on an abdominal radiograph when gas is outlining both sides of the bowel wall, i.e. gas within the bowel's lumen and gas within the peritoneal cavity. It is seen with large amounts of pneumoperitoneum (>1000 ...
Article
AAST spleen injury scale
The American Association for the Surgery of Trauma (AAST) splenic injury scale, revised in 2018, is the most widely used grading system for splenic trauma.
The 2018 update incorporates "vascular injury" (i.e. pseudoaneurysm, arteriovenous fistula) into the imaging criteria for visceral injury 4...
Article
AAST liver injury scale
The AAST (American Association for the Surgery of Trauma) liver injury scale, revised in 2018, is the most widely used liver injury grading system 3.
The 2018 update incorporates "vascular injury" (i.e. pseudoaneurysm, arteriovenous fistula) into the imaging criteria for visceral injury 3.
Cla...
Article
AAST kidney injury scale
The American Association for the Surgery of Trauma (AAST) renal injury scale, updated in 2018, is the most widely used grading system for renal trauma.
The 2018 update incorporates "vascular injury" (i.e. pseudoaneurysm, arteriovenous fistula) into the imaging criteria for visceral injury.
Cla...
Article
Adrenal adenoma
Adrenal adenomas (alternative plural: adenomata) are the most common adrenal lesion and are often found incidentally during abdominal imaging for other reasons. In all cases, but especially in the setting of known current or previous malignancy, adrenal adenomas need to be distinguished from adr...
Article
Adrenal washout
Adrenal washout can be calculated using the density value of an adrenal mass on non-enhanced, portal venous phase and 15-minute delayed CT scans (density measured in Hounsfield units (HU)). It is primarily used to diagnose adrenal adenoma.
absolute washout
[(HUportal venous phase) - (HUdelayed...
Article
Biliary ascariasis
Ascariasis is the commonest helminthic infection worldwide and estimated to affect nearly 1 billion people (25% of the population). The disease is transmitted by Ascaris lumbricoides which belongs to the nematode family (roundworms).
Lifecycle
Infection occurs by ingestion of contaminated food...
Article
Lung
The lungs are the functional units of respiration and are key to survival. They contain 1500 miles of airways, 300-500 million alveoli and have a combined surface area of 70 square meters (half a tennis court). Each lung weighs approximately 1.1 kg. They are affected by a wide range of pathology...
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
Congenital aortic stenosis
Congenital aortic stenosis broadly refers to a congenital narrowing of the aortic lumen. Although the term can mean narrowing at any point, it often relates to a narrowing of the aortic valve. As a broad group, there can be some overlap with ascending aortic coarctation depending on the definiti...
Article
Cerebral venous thrombosis
Cerebral venous thrombosis (CVT) (plural: thromboses) refers to the occlusion of venous channels in the cranial cavity, including dural venous thrombosis, cortical vein thrombosis and deep cerebral vein thrombosis. They often co-exist and the clinical presentation among them is very similar and ...
Article
Cerebral vasospasm following subarachnoid hemorrhage
Cerebral vasospasm following subarachnoid hemorrhage is a major complication of subarachnoid hemorrhage (SAH). It is overtaking rebleed as the major cause of mortality and morbidity in the subgroup of patients with SAH who reach the hospital and receive medical care. It usually occurs after a fe...
Article
Salpingitis isthmica nodosa
Salpingitis isthmica nodosa, sometimes also referred to as perisalpingitis isthmica nodosa or diverticulosis of the fallopian tube, refers to nodular scarring of the fallopian tubes. In very early stages, the tubes may appear almost normal. As scarring and nodularity progress, the changes become...
Article
Delayed cerebral ischemia
Delayed cerebral ischemia (DCI) is a frequent complication of aneurysmal subarachnoid hemorrhage. It contributes substantially to the morbidity and mortality following subarachnoid hemorrhage. It has traditionally been thought to be due to symptomatic vasospasm related to subarachnoid hemorrhage...
Article
Kidneys
The kidneys are paired retroperitoneal organs that lie at the level of the T12 to L3 vertebral bodies.
Gross anatomy
Location
The kidneys are located to either side of the vertebral column in the perirenal space of the retroperitoneum, within the posterior abdominal wall. The long axis of the...
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