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.

1,079 results found
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Aortic hiatus

The aortic hiatus is one the three major apertures through the diaphragm and lies at the level of T12. Strictly speaking, it is not a real aperture in the diaphragm, but an osseoaponeurotic opening between it and the vertebral column.  The hiatus is situated slightly to the left of the midline ...
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Aortoenteric fistula

Aortoenteric fistula are pathologic communications between the aorta (or aortoiliac tree) and the gastrointestinal tract, and represent an uncommon cause of catastrophic gastrointestinal haemorrhage. Aortic fistulas may be considered primary (associated with complicated abdominal aortic aneurys...
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Aphthoid ulceration

Aphthoid ulcers are shallow ulcers of the gastrointestinal mucosa. Pathology Aetiology infective inflammatory conditions Yersinia enterocolitis amoebic enterocolitis cytomegalovirus enterocolitis noninfective inflammatory conditions Crohn disease idiopathic granulomatous gastritis vasc...
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Appendiceal carcinoid

Appendiceal carcinoids are rare overall but represent the most common tumour of the appendix. The appendix is also one of the most common (but not the most common) locations for gastrointestinal carcinoid tumours.  Clinical presentation Appendiceal carcinoids can present as the obstructive cau...
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Appendiceal diverticulitis

Appendiceal diverticulitis is a rare condition in which there is acute inflammation of a diverticulum arising from the vermiform appendix. Epidemiology Historically appendiceal diverticulitis has been thought to be a rare diagnosis. However a study from 2015 which retrospectively reviewed the ...
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Appendiceal intussusception

Appendiceal intussusception happens when appendix segment is pulled into itself or into the cecum. This condition can mimic various chronic and acute abdominal conditions. It is an important entity to recognise since it could be mistaken for a caecal mass. Epidemiology Appendiceal intussuscept...
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Appendiceal mucocele

Appendiceal mucoceles occur when there is an abnormal accumulation of mucin causing abnormal distention of the vermiform appendix due to various neoplastic or non-neoplastic causes. Epidemiology The reported prevalence at appendectomy is 0.2-0.3%. They are thought to typically present in middl...
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Appendicitis

Appendicitis is inflammation of the vermiform appendix. It is a very common condition in general radiology practice and is one of the main reasons for abdominal surgery in young patients. CT is the most sensitive modality to detect appendicitis. Epidemiology Acute appendicitis is typically a d...
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Appendicitis (summary)

This is a basic article for medical students and other non-radiologists Appendicitis occurs when there is inflammation of the vermiform appendix. It is a very common condition and is a major cause of abdominal surgery in young patients. CT is the most sensitive modality to detect appendicitis a...
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Appendicolith

An appendicolith is a calcified deposit within the appendix. They are present in a large number of children with acute appendicitis and may be an incidental finding on an abdominal radiograph or CT. Incidence may be increased among patients with a retrocaecal appendix. Overall they are seen in 1...
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Appendicular abscess

Appendicular abscess is considered the most common complication of acute appendicitis, in particular after a perforated appendix.  Radiographic features Appendicular abscesses can arise either in the peritoneal cavity or the retroperitoneal space. Ultrasound Ultrasound is the first investiga...
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Appendicular artery

The appendicular artery is a branch of the ileal or posterior caecal branch of the ileocolic artery, which is from the superior mesenteric artery. It courses posteriorly to the terminal ileum in the free wall of the mesoappendix to supply the appendix.
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Appendix

The appendix or vermiform appendix is a blind muscular tube that arises from the caecum, which is the first part of the large bowel. Gross anatomy The appendix arises from the posteromedial surface of the caecum, approximately 2-3 cm inferior to the ileocaecal valve, where the 3 longitudinal b...
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Appleby procedure

The Appleby procedure is a type of pancreatic cancer resection.  For some patients with pancreatic cancer involving the body and tail of the pancreas, involvement of the coeliac axis is a classic contraindication to pancreaticoduodenectomy (Whipple procedure).  With the Appleby procedure, ther...
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Apple core sign (colon)

The apple core sign, also known as a napkin ring sign (bowel), is most frequently associated with constriction of the lumen of the colon by a stenosing annular colorectal carcinoma. Differential diagnosis The appearance of the apple-core lesion of the colon also can be caused by other diseases...
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Apple-peel intestinal atresia

Apple-peel intestinal atresia, also known as type IIIb or Christmas tree intestinal atresia, is a rare form of small bowel atresia in which the duodenum or proximal jejunum ends in a blind pouch and the distal small bowel wraps around its vascular supply in a spiral resembling an apple peel. Oft...
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Arc of Buhler

The arc of Buhler (AOB) is a persistent embryonic anastomotic branch between the 10th and 13th ventral segmental arteries, resulting in a connection between the coeliac artery and superior mesenteric artery (SMA). This arch is independent of both the gastroduodenal and dorsal pancreatic artery. ...
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Arc of Riolan

The arc of Riolan, also known as the mesenteric meandering artery (of Moskowitz) or central anastomotic mesenteric artery, is an arterioarterial anastomosis between the superior and inferior mesenteric arteries. Gross anatomy It is an inconstant artery that connects the proximal superior mesen...
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Areae gastricae

Areae gastricae are a normal finding on double contrast images of the stomach. Radiographic features fine reticular network of barium-coated grooves between 1-5 mm islands/areas of gastric mucosa may be seen in ~70-80% of patients if there is adequate high-density barium coating of the stomac...
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A-rings (oesophagus)

A-rings are a type of distal oesophageal ring. They are above the B-ring and occur a few centimetres proximal to the gastro-oesophageal junction. They represent a physiological contraction of oesophageal smooth muscle covered by mucosa. A-rings are uncommonly symptomatic.
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Arrowhead sign (caecum)

The arrowhead sign refers to the focal caecal thickening centred on the appendiceal orifice, seen as a secondary sign in acute appendicitis. The contrast material in the caecal lumen assumes an arrowhead configuration, pointing at the appendix.   The arrowhead sign is applicable only when enter...
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Asbestos related diseases

Asbestos related disease, in particular affecting the lung, comprise of a broad spectrum of entities related to the inhalational exposure to asbestos fibres. They can be divided into benign and malignant changes 1-3. Benign pleural and parenchymal lung disease asbestos related benign pleural d...
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Ascariasis

Ascariasis is due to infection with the Ascaris lumbricoides adult worm and typically presents with gastrointestinal or pulmonary symptoms, depending on the stage of development.   Epidemiology Ascaris lumbricoides is widely distributed in tropical and subtropical regions and in other humid ar...
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Ascaris-induced pancreatitis

Ascaris-induced pancreatitis is the most common form of parasite-induced pancreatitis. Epidemiology Ascariasis in parts of India is the second most common form of pancreatitis after gallstones 1. It is rare outside of endemic regions however. Clinical presentation The presentation will be si...
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Ascending colon

The ascending colon is the second part of the large bowel. Gross anatomy The ascending colon is the continuation of the caecum superior to the ileocaecal valve. It is secondarily retroperitoneal, although it has its own mesentery in approximately 25% of patients and is 15 cm in length 1,2. Th...
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Ascites

Ascites is defined as an abnormal amount of intraperitoneal fluid. Clinical presentation Patients with a large volume of ascites can present with abdominal distension (which may be painful), nausea, vomiting, dyspnoea and peripheral oedema 7, 9. Pathology Ascitic fluid is traditionally chara...
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Asplenia

Asplenia refers to absence of the spleen thereby leading to deficient splenic function. Epidemiology Seen in 3% of neonates with structural heart disease and in 30% of patients who die from cardiac malposition. The male-to-female ratio is 2:1. Pathology Asplenia can be classified into two  t...
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Atrial-oesophageal fistula

Atrio-oesophageal fistulas are rare pathological connections between the left atrium and the oesophagus.  Clinical presentation The presentation is non-specific. Patients may complain of fever, malaise, and/or dysphagia, or present with neurological symptoms 3.  Pathology The chief cause of ...
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Atrophic gastritis

Atrophic gastritis is a chronic condition of autoimmune and non-autoimmune aetiology.  Pathology Two types of atrophic gastritis have been described 1-3: type A: autoimmune gastric body and fundus atrophy secondary to antiparietal cell antibodies decreased secretion of acid and intrinsic fa...
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Autoimmune pancreatitis

Autoimmune pancreatitis (AIP) is a form of chronic pancreatitis associated with autoimmune manifestations on clinical, histological, and laboratory grounds 1. Distinguishing this entity from other forms of chronic pancreatitis (such as alcohol-induced) is important as steroid treatment is effec...
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Autosplenectomy

Autosplenectomy denotes spontaneous infarction of the spleen with resulting hyposplenism. Epidemiology Autosplenectomy is most frequently encountered in patients with homozygous sickle cell disease, although it has also been reported in pneumococcal septicaemia 1, and SLE 2. The demographics t...
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Backwash ileitis

Backwash ileitis is seen in patients with ulcerative colitis (UC), where the entire colon is involved. In such cases the terminal ileum is oedematous. Backwash ileitis extends contiguously backward from the caecum without skip regions. One source estimates it to occur in 6% of patients with UC,...
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Ball of wool sign (hydatid cyst)

The ball of wool sign, also referred to as the yarn sign or congealed water lily sign, is an ultrasound appearance, representing degeneration of hydatid cysts (WHO class CE 4). The inner side of the cyst detaches from the cyst wall and folds on itself, causing a change from anechoic (fluid) to a...
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Balloon-occluded retrograde transvenous obliteration

Balloon-occluded retrograde transvenous obliteration (BRTO) is a technique used by interventional radiologists in the treatment of gastric varices, particularly those with prominent infra-diaphragmatic portosystemic venous shunts (e.g. gastro-renal and gastro-caval shunts). The technique is mor...
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Balthazar score

The Balthazar score is a subscore within the CT severity index (CTSI) for grading of acute pancreatitis.  The CTSI sums two scores: Balthazar score: grading of pancreatitis (A-E) grading the extent of pancreatic necrosis The Balthazar score was originally used alone, but the addition of a sc...
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Bannayan–Riley–Ruvalcaba syndrome

Bannayan–Riley–Ruvalcaba syndrome (BRRS or BRR syndrome) is a very rare autosomal dominant hamartomatous disorder caused by a mutation in the PTEN gene. It is considered in the family of hamartomatous polyposis syndrome. There are no formal diagnostic criteria for this disease, but characterist...
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Bariatric intragastric balloon therapy

Bariatric intragastric balloon therapy is a relatively new form of weight loss therapy, which involves a balloon being endoscopically-placed or swallowed and inflated inside the lumen of the stomach. The balloon resides in the stomach and the mechanism of action is presumably due to stretching t...
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Barium peritonitis

Barium peritonitis is a rare complication of gastrointestinal fluoroscopy, and occurs when there is gastrointestinal tract perforation and spillage of barium into the peritoneal cavity.  Pathology Barium in the peritoneal cavity is treated as a foreign body with resultant immune response that ...
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Barium studies of the small bowel

Barium studies of the small intestine are still considered an effective modality to show the bowel loops in a cost-effective way. Procedure Small bowel follow through (SBFT) or transit study  routine investigation for delineation of all parts the small bowel done with barium meal after havin...
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Barium sulfate

Barium sulfate (BaSO4), often just called barium in radiology parlance, is a salt of barium (Ba), a metallic chemical element with atomic number 56. Barium is considered one of the heavy metals. Unlike barium and many of its other salts, barium sulfate is insoluble in water and therefore very li...
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Barium swallow

Barium swallow is a dedicated test of the pharynx, oesophagus, and proximal stomach, and may be performed as a single or double contrast study. The study is often "modified" to suit the history and symptoms of the individual patient, but it is often useful to evaluate the entire pathway from the...
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Barrett oesophagus

Barrett oesophagus is a term for intestinal metaplasia of the oesophagus. It is considered the precursor lesion for oesophageal adenocarcinoma. Epidemiology Barrett oesophagus is thought to have a prevalence of 3-15% in patients with reflux oesophagitis. Mean age at diagnosis is 55 years old 5...
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Beak sign (pyloric stenosis)

Beak sign in pyloric stenosis is one of the fluoroscopic (barium meal) findings which is useful in the diagnosis of congenital hypertrophic pyloric stenosis.  Radiographic features Barium meal A beak-like tapering projection of barium is seen entering into the narrowed and compressed pyloric ...
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Behçet disease

Behçet disease is a multisystemic and chronic inflammatory vasculitis of unknown aetiology. Epidemiology The mean age at which Behçet disease occurs is 20-30 years. The disease is most prevalent in the Mediterranean region, Middle East and East Asia. The highest incidence has been reported in ...
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Benign oesophageal lesions

Benign oesophageal lesions are less symptomatic than malignant oesophageal lesions, making up for only 1% of clinically apparent oesophageal lesions. Pathology oesophageal leiomyoma (>50%) may calcify oesophageal fibrovascular polyp (~12.5%) may contain fat oesophageal duplication cyst (10...
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Benign post-traumatic pseudopneumoperitoneum

Benign post-traumatic pseudopneumoperitoneum is the presence of ectopic gas typically between the 5th-10th intercostal spaces after high-energy trauma in the absence of other causes of pseudopneumoperitoneum such as pneumomediastinum 9.  Epidemiology Occurs with an incidence of 5% post-trauma...
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Bethesda criteria of hereditary non-polyposis colorectal cancer

The Bethesda criteria are an alternative to the Amsterdam criteria for the clinical diagnosis of hereditary non-polyposis colorectal cancer (HNPCC).  Diagnosis of HNPCC is made if any of the following criteria are fulfilled: Amsterdam criteria are met 2 or more HNPCC related malignancies  pa...
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Bezoar

Bezoars are accumulations of indigestible contents within the gastrointestinal tract 2.  Pathology There are several types depending on the predominant components: trichobezoar: a bezoar formed from hair, this has also been called Rapunzel syndrome when the tail of the trichobezoar extends so...
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Bilateral adrenal gland hyperenhancement

Bilateral adrenal gland hyperenhancement or intense adrenal enhancement may be a feature of hypotension and forms part of the CT hypoperfusion complex. Adrenal gland hyperenhancement has been described in paediatric and small adult series or individual cases of haemorrhagic shock, pancreatitis,...
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Biliary cast syndrome

Biliary cast syndrome is a complication that occurs after liver transplantation, where dark solid bilirubin casts develop in the biliary tree, causing biliary obstruction. Terminology This should be differentiated from biliary sludge, which represents thickened bile that has not precipitated. ...
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Biliopancreatic diversion

Biliopancreatic diversion was a development on the jejunoileal bypass type of bariatric surgery. It can be performed with or without a duodenal switch. The procedure involves distal gastrectomy, with formation of a gastric pouch gastroenterostomy, with formation of a ~250 cm Roux limb (normal...
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Billroth II gastrojejunostomy

Billroth II gastrojejunostomy is a procedure that has been performed for tumour or severe ulcer disease in the distal stomach. There are many variations on the procedure, but they generally involve resection of the diseased portion of the distal stomach and a side-to-side anastomosis of the res...
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Bird beak sign (oesophagus)

The bird's beak sign of the oesophagus is used to refer to the tapering of the inferior oesophagus in achalasia. The same appearance (although it is difficult to see the similarity) is also referred to as the rat-tail sign. The appearance, although classically occurring in primary achalasia, ca...
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Bird beak sign (right colon)

The bird beak sign of the right colon is tapering obstruction of the inferior part of right colon seen on contrast enema or CT scan with rectal contrast indicating caecal volvulus. This sign can help to differentiate caecal volvulus from caecal bascule, in particular on a contrast/barium enema ...
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Bird beak sign (sigmoid colon)

Bird's beak sign of the sigmoid is one of the signs of sigmoid volvulus. It represents gradual narrowing/tapering of sigmoid colon up to the level of obstruction during contrast/barium insertion to the rectum or on CT. When located in the sigmoid colon, it suggests the diagnosis of sigmoid volv...
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Blind loop syndrome

Blind loop syndrome (or "blind pouch syndrome") is an event that may occur after an end-to-end or end-to-side bowel anastomosis. Dilatation and stasis of the bypassed bowel may lead to bacterial overgrowth, breakdown of bile salts, and result in nutritional problems. It may even eventually lead ...
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Bochdalek hernia features (mnemonic)

A helpful mnemonic for remembering the features of a Bochdalek hernia is: BBBBB Mnemonic B: Bochdalek B: big B: back and medial, usually on the left side B: baby B: bad (associated with pulmonary hypoplasia)
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Body packing

Body packing refers to the internal concealment of drugs within the gastrointestinal tract or other orifices. People who do this may be called body packers, (drug) mules, stuffers, couriers or swallowers. Drugs may be concealed within condoms, foil, latex or cellophane.  Epidemiology There is ...
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Boerhaave syndrome

Boerhaave syndrome refers to an oesophageal rupture secondary to forceful vomiting and retching. Epidemiology It tends to be more prevalent in males, with alcoholism a risk factor. The estimated incidence is ~ 1:6000. Clinical presentation They are often associated with the clinical triad (M...
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Bouveret syndrome

Bouveret syndrome refers to a gastric outlet obstruction secondary to impaction of a gallstone in the pylorus or proximal duodenum. Thus, it can be considered a very proximal form of gallstone ileus.  Clinical presentation Bouveret syndrome occurs most commonly in elderly women. The presenting...
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Bowel and mesenteric trauma

Bowel and mesenteric trauma can result from blunt force, penetrating and iatrogenic trauma. Epidemiology The bowel and mesentery are injured in ~2.5% (range 0.3-5%) of blunt force abdominal trauma 1,3,5,8. However not surprisingly, bowel and mesenteric injuries are more frequent after penetrat...
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Bowel dilatation (summary)

This is a basic article for medical students and other non-radiologists Bowel dilatation is a relatively non-specific sign than can be seen on most imaging modalities. In bowel obstruction, dilatation may be demonstrated on a plain radiograph providing the bowel is filled with gas. Reference a...
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Bowel obstruction

Bowel obstructions are common and account for 20% of admissions with "surgical abdomens". Radiology is important in confirming the diagnosis and identifying the underlying cause. Bowel obstructions are usually divided according to where the obstruction occurs, and since imaging appearances, und...
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Bowel perforation

Bowel perforation can occur in many different settings, but the more common are bowel obstruction (both small and large) bowel ischaemia severe ulcer disease diverticular disease infection malignant diseases gastrointestinal tumors direct tumour invasion trauma: blunt or penetrating au...
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Bowel perforation (summary)

This is a basic article for medical students and other non-radiologists Bowel perforation is an acute surgical emergency where there is a release of gastric or intestinal contents into the peritoneal space. Reference article This is a summary article; read more in our article on bowel perfora...
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Bowel sacculation (mnemonic)

A mnemonic to remember causes of bowel sacculation is: MISC Mnemonic M: metastasis I: ischaemia S: scleroderma C: Crohn disease
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Bowel wall thickening

Bowel wall thickening is a useful finding on imaging studies and has a number of different causes. Pathology The reason for bowel wall thickening depends on the underlying aetiology but includes submucosal oedema, haemorrhage, and neoplastic infiltration. Radiographic features In describing ...
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Bronchogenic cyst vs oesophageal duplication cyst

Bronchogenic cysts and oesophageal duplication cysts are embryological foregut duplication cysts and are also differential diagnoses for a cystic mediastinal mass. Differences Symptoms asymptomatic bronchogenic cyst symptomatic oesophageal cyst in the case of peptic ulceration Plain radiogr...
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Brunner gland adenoma

Brunner gland adenomas are hyperplastic areas of the Brunner glands within the duodenum that are greater than 1 cm. They tend to be 1-2 cm in diameter, although case reports have described tumours of up to 12 cm diameter. Where the diameter of focal hyperplasia is less than 1 cm, the term Brunne...
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Brunner gland hyperplasia

Brunner gland hyperplasia results from disproportionate overgrowth of Brunner glands in the duodenum as a result of hyperacidity. Hyperplasia begins at the pylorus and extends distally within the first 2/3rds of the duodenum. Where the focal growth of hyperplastic cells is greater than 1 cm in ...
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Brunner glands

Brunner glands are compound tubular submucosal glands found in the duodenum. They are only found proximal to the sphincter of Oddi. Related pathology Brunner gland hyperplasia Brunner gland adenoma
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Bulging duodenal papilla

Major duodenal papilla is a conic or cylindric protuberance at the medial aspect of the descending or horizontal duodenum at the site of the sphincter of Oddi. It is finding on small bowel follow-though (and endoscopy) and has a relatively long differential. On cross sectional imaging, the unde...
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Buried bumper syndrome

Buried bumper syndrome (BBS) is a rare but important complication in patients with percutaneous endoscopic gastrostomy (PEG) tube, occurring by migration of the internal bumper along its track. The tube may get lodged anywhere between the gastric wall and the skin and lead to life-threatening co...
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CA 19-9

CA 19-9 (carbohydrate antigen 19-9 or cancer antigen 19-9) is a serum antigen (monosialoganglioside) that has increased diagnostic use in the management of several malignancies, mainly of hepatopancreaticobiliary origin. It is non-specific, however, and can rise in both malignant and non-maligna...
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Caecal bar sign

The caecal bar sign is a secondary sign in acute appendicitis. It refers to the appearance of inflammatory soft tissue at the base of the appendix, separating the appendix from the contrast-filled caecum. See also arrowhead sign
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Caecal bascule

Caecal bascule is an uncommon type of caecal volvulus in which the caecum folds up over itself in an anteromedial orientation. In contrast to the more common forms of volvulus, there is no axial "twisting" component 4.  A caecal bascule may occur in the setting of a large and mobile caecum and c...
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Caecal volvulus

Caecal volvulus describes torsion of the caecum around its mesentery which often results in obstruction. If unrecognised, it can result in bowel perforation and faecal peritonitis. Epidemiology Caecal volvulus accounts for ~10% of all intestinal volvuluses, and generally occur in somewhat youn...
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Caecum

The caecum is the first part of the large bowel and lies in the right lower quadrant of the abdomen.  Gross anatomy Blind-ending sac of bowel that lies below the ileocaecal valve, above which the large intestine continues as the ascending colon. The caecum measures 6 cm in length and can have ...
Article

Candida oesophagitis

Candida oesophagitis is the most common cause of infectious oesophagitis that commonly affects immunocompromised patients. On imaging, it is characterised by irregular plaque-like lesions separated by normal mucosa and small (<1cm) ulcers, which are assessed on oesophagogram studies.   Epidemio...
Article

Cantlie's line

Cantlie's line is a vertical plane that divides the liver into left and right lobes creating the principal plane used for hepatectomy. It extends from the inferior vena cava posteriorly to the middle of the gallbladder fossa anteriorly. It contains the middle hepatic vein which divides the live...
Article

Carbolic acid poisoning symptoms (mnemonic)

The symptoms of carbolic acid poisoning can be recalled using the mnemonic: 5 Cs Mnemonic C: CNS depression C: constricted pupil C: carboluria (smoky urine) C: cartilage C: corneal deposition
Article

Carcinoembryonic antigen

Serum carcinoembryonic antigen (CEA) is a cell-adhesive glycoprotein that was discovered in colorectal cancer in 1965, and is hence one of the oldest and most used tumour markers. Its name derives from its normal expression in fetoembryonic liver, gut and pancreas tissue. Normal range of CEA is...
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Carcinogens

Carcinogens are substances known to cause cancer. They include: Brain vinyl chloride Nasopharynx / nasal passage nickel wood dust chromium Thyroid ionising radiation (not technically a substance) Skin arsenic coal tars polyaromatic hydrocarbons (PAH) Lungs arsenic asbestos chloro...
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Carcinoid syndrome

Carcinoid syndrome refers to a spectrum of symptoms that result from excessive hormone (mainly serotonin) secretion.  Epidemiology Occurs equally between the sexes, most commonly in the 40-70 year age group 3. Clinical presentation Diarrhoea is the most common and earliest symptom but others...
Article

Carcinoid tumour

Carcinoid tumours are a type of neuroendocrine tumour that can occur in a number of locations. Carcinoid tumours arise from endocrine amine precursor uptake and decarboxylation (APUD) cells that can be found throughout the gastrointestinal tract as well as other organs (e.g. lung). In general, t...
Article

Carcinosarcoma

Carcinosarcomas are highly malignant biphasic tumours with both carcinomatous (epithelial) and sarcomatous (bone, cartilage, or skeletal muscle) components.  Pathology It can arise in many organs: lung 5: pulmonary carcinosarcoma oesophagus 1: oesophageal carcinosarcoma genitourinary tract ...
Article

Carman meniscus sign

The Carman meniscus sign describes the lenticular shape of barium in cases of large and flat gastric ulcers, in which the inner margin is convex toward the lumen. It usually indicates a malignant ulcerated neoplasm; in cases of benign gastric ulcers, the inner margin is usually concave toward th...
Article

Carney-Stratakis syndrome

Carney-Stratakis syndrome is a rare autosomal dominant condition comprising of familial paraganglioma and gastric stromal sarcoma. Terminology It is considered to be distinct from, but perhaps related to, the Carney triad 1. Neither should be confused with the unrelated Carney complex. Histor...
Article

Carney triad

The Carney triad is a rare syndrome defined by the coexistence of three tumours: extra-adrenal paraganglioma (e.g. spinal paraganglioma) initially, only functioning extra-adrenal paragangliomas were included, but subsequent work includes non-functioning extra-adrenal paragangliomas 1 gastric ...
Article

Cases in radiology (video tutorials)

The cases featured in these video lectures are specifically selected to teach important concepts in radiology over a broad range of topics. The tutorials vary in difficulty from basic to advanced. For maximum learning, try the cases for yourself in Radiopaedia quiz mode first.  We love this ser...
Article

Casoni skin test

The Casoni skin test is a hypersensitivity based skin test used to detect hydatid disease. Although once a major test in diagnosing hydatid disease it has largely been superseded by newer more sensitive, specific and safer serological tests. Technique Sterile fluid (0.25 mL) of hydatid cyst or...
Article

Castleman disease

Castleman disease, also known as angiofollicular lymph node hyperplasia or giant lymph node hyperplasia, is an uncommon benign B-cell lymphoproliferative condition. It can affect several regions of the body although commonly described as a solitary mediastinal mass. There are two distinct subty...
Article

Caterpillar sign

The caterpillar sign is a radiological sign described in pyloric stenosis. It refers to the appearance of stomach on an upper gastrointestinal radiographic series or plain abdominal radiograph 1,2. On these imaging modalities in a patient with pyloric stenosis, the stomach appears distended, ai...

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