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.

81 results found
Article

Apple core sign (colon)

The apple core sign, also known as the 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 diseas...
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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 ...
Article

Bulging duodenal papilla

Bulging duodenal papilla​ is a conical or cylindrical protuberance at the medial aspect of the descending or horizontal duodenum at the site of the sphincter of Oddi. It is a finding on small bowel follow-though (and endoscopy) and has a relatively long differential. On cross-sectional imaging, ...
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Colonic stricture

Colonic strictures can be long (>10 cm) or short. Short scirrhous colorectal carcinoma (apple core sign) post surgical (anastamotic stricture) Long malignancy scirrhous colorectal carcinoma gastrointestinal lymphoma inflammatory bowel disease ulcerative colitis Crohn disease post radi...
Article

Complications following gastric banding

There are many complications that can occur following gastric banding. It is helpful to divide these into early and late post-surgical complications. Clinical presentation Although the exact mode of presentation can vary depending on the underlying complication common modes of presentation tha...
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Complications post optical colonoscopy

Complications post optical colonoscopy are most commonly assessed by CT if patients present with abdominal symptoms post colonoscopy. Complications include: bowel perforation (most common) pneumoperitoneum pneumoretroperitoneum pneumomediastinum pneumothorax lower gastrointestinal haemorrh...
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Cystic lesions of the pancreas (differential)

The differential for cystic lesions of the pancreas includes: unilocular pancreatic pseudocyst intraductal papillary mucinous neoplasm (IPMN) serous cystadenoma uncommonly uni/macrolocular simple pancreatic cyst pancreatic cysts occur in association with  von Hippel Lindau syndrome autos...
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Cystic (necrotic) lymph nodes

Cystic or necrotic appearing lymph nodes can be caused by a number of infectious, inflammatory or malignant conditions: Systemic squamous cell carcinoma metastases treated lymphoma leukaemia plasmacytoid T-cell leukaemia acute myeloid leukaemia viral lymphadenitis herpes simplex lymphade...
Article

Cystic retroperitoneal lesions

Cystic retroperitoneal lesions can carry a relatively broad differential, which includes: retroperitoneal lymphangioma retroperitoneal mucinous cystadenoma retroperitoneal cystic teratoma retroperitoenal cystic mesothelioma pseudomyxoma retroperitonei with cystic change perianal mucinous c...
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Diaphragmatic rupture

Diaphragmatic rupture often results from blunt abdominal trauma. The mechanism of injury is typically a motor-vehicle collision. Epidemiology Given that the most common mechanism is motor vehicle collisions, it is perhaps unsurprising that young men are most frequently affected. The estimated ...
Article

Diffuse colonic nodularity (differential)

Diffuse colonic nodularity on barium enema or CT colonography has a range of possible aetiologies: lymphoid hyperplasia (tend to be small and discrete) lymphoma (tend to be larger nodules and confluent) urticaria (closely spaced polygonal lesions, history is often helpful) pseudomembranous c...
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Diffuse small bowel disease

Diffuse small bowel disease may be caused by a number of conditions may be generalised multisystem disorders or conditions that effect the bowel in a global fashion: sprue scleroderma Whipple's disease amyloidosis hypoproteinaemia giardiasis intramural haemorrhage radiation enteritis sm...
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Discrete colonic ulceration

Discrete colonic ulcerations are nonspecific findings, and can be due to: Crohn disease infective colitis Yersinia entercolitis shigellosis tuberculosis cytomegalovirus (CMV) amoebic colitis vasculitic colitis Behcet disease
Article

Double bubble sign (duodenum)

The double bubble sign is seen in infants and represents dilatation of the proximal duodenum and stomach. It is seen in both radiographs and ultrasound, and can be identified antenatally 2. Pathology Causes include 1,2: congenital obstruction duodenal web duodenal atresia duodenal stenosis...
Article

Dysphagia

Dysphagia refers to subjective awareness of difficulty or obstruction during swallowing. It is a relatively common and increasingly prevalent clinical problem. Odynophagia is the term for painful swallowing. Fluoroscopy is the mainstay of imaging assessment but manometry can help evaluate the o...
Article

Enteritis

Enteritis (plural: enteritides) refers to inflammation of the small bowel. When associated with inflammation of the stomach, the term gastroenteritis is used which is usually caused by infection. Pathology Aetiology infection infective enteritis eosinophilic enteritis ischaemia inflammato...
Article

Foregut duplication cyst

Foregut duplication cysts are a type of congenital duplication cyst. They are sometimes classified under bronchopulmonary foregut malformations. Entities classified as foregut duplication cysts include: bronchogenic cysts neurenteric cysts other enteric cysts oesophageal duplication cysts ...
Article

Gasless abdomen

A gasless abdomen refers to a paucity of gas on abdominal radiography, and the specific cause can usually be identified when the patient's history is known. Common causes include: small bowel obstruction bowel ischaemia congenital atresia ascites pancreatitis gastroenteritis large abdomin...
Article

Gastric outlet obstruction

Gastric outlet obstruction is a syndrome resulting from mechanical obstruction of stomach emptying. Pathology Aetiology Gastric outlet obstruction can be due to malignant or benign causes. Malignant adenocarcinoma (second most common 4) GIST lymphoma (less common than other malignancies a...
Article

Granular mucosal pattern of the oesophagus (differential)

Granular mucosal pattern of the oesophagus represents very fine nodularity of the oesophageal mucosal surface. This finding is non-specific and may represent: reflux oesophagitis (most common) Candida oesophagitis glycogenic acanthosis Barrett oesophagus superficial spreading oesophageal ca...
Article

Haemoperitoneum

Haemoperitoneum (plural: haemoperitoneums) is the presence of blood within the peritoneal cavity. Pathology Aetiology penetrating or non-penetrating abdominal trauma (often with associated organ injury) 1 ruptured ectopic pregnancy ovarian cyst rupture aneurysm or pseudoaneurysm rupture n...
Article

Hepatosplenomegaly

Hepatosplenomegaly is simply the simultaneous presence of a pathologically-enlarged liver (hepatomegaly) and spleen (splenomegaly). Pathology Aetiology Infection Many, many infections can produce a mild concurrent enlargement of the liver and spleen. This list is by no means exhaustive! vir...
Article

Hiccups

Hiccups (or hiccoughs), medical term singultus (rarely used), are an unpleasant phenomenon, experienced by everyone on occasion, and usually self-limiting. However the much rarer intractable chronic form can be extremely debilitating. Epidemiology Hiccups are a symptom that has probably been e...
Article

HIV/AIDS: gastrointestinal manifestations

Gastrointestinal manifestations of AIDS are protean and can be broadly divided into opportunistic infections and tumours: Infections viral  cytomegalovirus (CMV) herpes simplex virus (HSV) primary infection with HIV fungal candidiasis histoplasmosis bacterial tuberculosis mycobacteriu...
Article

HIV associated neoplasms

HIV-associated neoplasms are numerous and can be broadly divided into two groups: AIDS-defining malignancies associated but not AIDS defining malignancies AIDS-defining malignancies The development of these malignancies in HIV affected individuals generally implies progression to AIDS 4: Ka...
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Intestinal failure

Intestinal failure is when a patient's native bowel is unable to digest and absorb the food, electrolytes, and fluids needed for normal growth and development.  Clinical presentation This often includes intractable diarrhoea, weight loss, dehydration, electrolyte imbalance, and malnutrition. ...
Article

Intra-abdominal calcification

Intra-abdominal calcification is common and the causes may be classified into four broad groups based on morphology: Concretions These are discrete precipitates in a vessel or organ. They are sharp in outline but the density and shape vary but in some cases they may be virtually pathognomonic:...
Article

Intra-abdominal calcification (neonatal)

Intra-abdominal calcification in a neonate can be caused by a number of pathologies that cause calcification within the peritoneal space or within organs. Pathology Aetiology Meconium peritonitis The commonest cause is meconium peritonitis which is the result of aseptic peritonitis secondary...
Article

Linitis plastica

Linitis plastica is a descriptive term usually referring to the appearance of the stomach, although the rectum can also be described this way. The appearance is said to be reminiscent of an old leather water-bottle. Pathology The underlying cause is usually a scirrhous adenocarcinoma with diff...
Article

Lower abdominal/pelvic calcification

Causes of calcifications in the lower abdomen and pelvis include: vascular calcifications atherosclerosis aneurysms phleboliths urogenital uterine fibroid ovarian dermoid prostatic calcification seminal vesicle and ductus deferens calcification bladder stones gallstones dropped stone...
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 ischaemic colitis vascular malformation vascular ectasia angiodysplasia arteriovenous ...
Article

Malignant oesophageal neoplasms

Malignant oesophageal neoplasms are much more common than benign oesophageal neoplasms, especially if the patient is symptomatic.  Pathology oesophageal carcinoma (90%) oesophageal squamous cell carcinoma (SCC) oesophageal spindle cell carcinoma oesophageal adenocarcinoma oesophageal neuro...
Article

Malignant vs benign gastric ulcer (barium)

Barium meal has been frequently used to differentiate malignant and benign gastric ulcers: Features suggesting benign gastric ulcer outpouching of ulcer crater beyond the gastric contour (exoluminal) smooth rounded and deep ulcer crater smooth ulcer mound smooth gastric folds that reach the...
Article

Maydl hernia

Maydl hernias are defined as the presence of two small bowel loops within a single hernial sac, that is, there are two efferent and two afferent loops of bowel, forming a "W" shape. This type of hernia is more prone to strangulation and necrosis. The intervening intra-abdominal loop is also at ...
Article

McBurney point

McBurney point is defined as a point that lies one-third of the distance laterally on a line drawn from the umbilicus to the right anterior superior iliac spine. Classically, it corresponds to the location of the base of the appendix 1. Clinically, McBurney point is relevant for the elicitation...
Article

Medical devices in the abdomen and pelvis

Medical devices in the abdomen and pelvis are important to be recognised, just like medical devices of the chest. Often we ignore these devices, considering them to be incidental and non-pathological, however it is essential to be aware of potential complications. Gastrointestinal tubes stomac...
Article

Megaoesophagus

Megaoesophagus or diffuse oesophageal dilatation can be caused by a variety of conditions.  Pathology Aetiology Some of the more common causes are given below 1-3: oesophageal dysmotility achalasia Chagas disease scleroderma distal obstruction malignant stricture, e.g. oesophageal cance...
Article

Mucinous cystic neoplasms of the pancreas

Mucinous cystic neoplasms of the pancreas are the most common cystic neoplasm of the pancreas and include: mucinous cystadenoma of pancreas mucinous cystadenocarcinoma of pancreas intraductal papillary mucinous neoplasms (IPMN) of the pancreas: sometimes classified separately
Article

Nodular filling defects of duodenum (differential)

Nodular filling defects due to mucosal lesions in the duodenum are due to a number of processes. For a differential list which includes non-mucosal lesions see duodenal filling defects. The differential diagnosis for mucosal lesions includes:  heterotopic gastric mucosa 1-2 mm clustered onl...
Article

Non-neoplastic solid lesions of the pancreas

Non-neoplastic solid lesions of the pancreas are conditions which may mimic pancreatic neoplasms on imaging. They include: focal pancreatitis autoimmune pancreatitis fatty infiltration-replacement intrapancreatic accessory spleen peripancreatic lymph node congenital anomalies prominent pa...
Article

Oesophageal dysmotility

Oesophageal dysmotility refers to the pathological disruption of the normal sequential and coordinated muscle motion of the oesophagus to transport food from the oropharynx to the stomach. It is an umbrella term used to refer to the common pathophysiological endpoint of dysmotility that can be c...
Article

Omental cake

Omental cake refers to infiltration of the omental fat by material of soft-tissue density. The appearances refer to the contiguous omental mass simulating the top of a cake. Masses on the peritoneal surfaces and malignant ascites may also be present.  Pathology The most common cause is metasta...
Article

Omphalomesenteric fistula

Omphalomesenteric fistula occurs as a result of failure of obliteration of the omphalomesenteric duct. It is one of the congenital fistulas of the gastrointestinal tract. The treatment of choice is often a partial transumbilical resection with umbilical restitution. See also gut fistulation
Article

Pancreatic atrophy

Pancreatic atrophy is non-specific and is common in elderly patients, although in younger patients it can be a hallmark of pathology. Most commonly it is associated with ageing, obesity and end-stage chronic pancreatitis.  It occurs principally with fatty replacement of the pancreas (pancreatic...
Article

Pancreatic calcifications

Pancreatic calcifications can arise from many aetiologies. Punctate intraductal calcifications chronic pancreatitis alcoholic pancreatitis (20-40%) 2  intraductal, numerous, small, irregular preponderant cause of diffuse pancreatic intraductal calcification gallstone pancreatitis (2%) 2 ​...
Article

Pancreatic neoplasms

There are numerous primary pancreatic neoplasms, in part due to the mixed endocrine and exocrine components. Classification Classification based on function exocrine: ~99% of all primary pancreatic neoplasms pancreatic ductal adenocarcinoma ~90-95% cystic neoplasm intraductal papillary muc...
Article

Pancreatitis

Pancreatitis (plural: pancreatitides) refers to inflammation involving the pancreas.  It has various forms which can be classified in many many ways according to time of onset, aetiological agent or associated pathology. acute pancreatitis interstitial oedematous pancreatitis necrotising pan...
Article

Pantaloon hernia

A pantaloon hernia (dual hernia, Romberg hernia or saddle bag hernia) is defined as ipsilateral, concurrent direct and indirect inguinal hernias. Hernial sacs are present on both sides of the inferior epigastric vessels, and separated by the posterior wall of the inguinal canal brought down by t...
Article

Periampullary tumours

Periampullary tumours are those that arise within 2 cm of the ampulla of Vater in the duodenum. Tumours that fall under this group include four main types of tumours 1,4 that will be approached in their specific articles: pancreatic head/uncinate process tumours: includes pancreatic ductal ade...
Article

Peritoneal calcification

Peritoneal calcification is seen in a limited number of conditions that result in calcification of peritoneal structures. Therefore, the differential diagnosis is small: psammoma bodies in malignancy (most frequently cystadenocarcinoma of the ovary): fine sand-like calcification pseudomyxoma p...
Article

PET-CT indications

PET-CT is a combination of cross-sectional anatomic information provided by CT and the metabolic information provided by positron emission tomography (PET). PET is most commonly performed with 2-[F-18]fluoro-2-deoxy-D-glucose (FDG). Fluorine-18 (F-18) is an unstable radioisotope and has a half-...
Article

Pneumatosis coli

Pneumatosis coli is a descriptive sign presenting radiographically as intramural gas limited to the colonic wall.  Terminology There are different terminologies in the medical literature, such as pneumatosis intestinalis, pneumatosis coli, and pneumatosis cystoides intestinalis. Pneumatosis in...
Article

Primary peritoneal neoplasms

Primary peritoneal neoplasms comprise an uncommon group of heterogeneous entities, which include: mesothelial derivatives primary (malignant) peritoneal mesothelioma peritoneal multicystic mesothelioma primary peritoneal well-differentiated papillary mesothelioma primary peritoneal adenomat...
Article

Primary pneumatosis intestinalis

Primary pneumatosis intestinalis (PPI) is a benign idiopathic condition in which multiple gas-filled cystic lesions are seen in the gastrointestinal tract wall. The changes are usually seen initially on radiography or CT with CT being the more sensitive test. Epidemiology Primary pneumatosis i...
Article

Pseudopneumoperitoneum

Pseudopneumoperitoneum describes any gas within the abdominal cavity that masquerades as free intraperitoneal gas or pneumoperitoneum when it is in fact contained within an organ. Correctly identifying pneumoperitoneum is important, but making the diagnosis in error may lead to further unnecessa...
Article

RASopathy

RASopathies are a class of developmental disorders caused by germline mutations in genes that encode for components or regulators of the Ras/mitogen-activated protein kinase (MAPK) pathway. Epidemiology As a group, RASopathies represent one of the most common malformation syndromes, with an in...
Article

Recreational drug use (radiological manifestations)

Radiological manifestations of recreational drug use are not infrequently seen as the use of recreational drugs is widespread. Epidemiology Interestingly, recent reports have suggested a decreasing incidence of reported drug use in the general population over the past decade, but it remains th...
Article

Rectal foreign bodies

Rectal foreign bodies are not uncommon in emergency departments around the world and potentially cause management difficulties. Epidemiology The incidence varies according to the region, said to be uncommon in Asia and most common in Eastern Europe 1. Typically patients are male with a wide ra...
Article

Retrorectal developmental cysts

Retrorectal developmental cysts are rare and mostly congenital benign lesions found in the retrorectal space:  spectrum of cystic teratomas retrorectal epidermoid cyst retrorectal dermoid cyst retrorectal teratoid cyst enteric cysts duplication cyst of the rectum tailgut duplication cyst ...
Article

Right iliac fossa mass (differential)

Right iliac fossa mass is a common clinical presentation and has a range of differentials that need to be excluded. Radiology plays an important role in this differentiation. Differential diagnosis appendicular mass appendicular abscess appendicular mucocele appendicular neoplasms ileocaec...
Article

Roux-en-Y gastric bypass surgery

In many centres, laparoscopic Roux-en-Y gastric bypass has become the most common bariatric procedure for morbid obesity.  In this operation, the stomach is stapled or divided to form a small pouch (typically <30 mL in volume), which empties into a Roux limb of the jejunum of varying length (ty...
Article

Sister Mary Joseph nodule

A Sister Mary Joseph nodule is a metastatic lesion involving the umbilicus. The most common primary source is an intra-abdominal adenocarcinoma. Epidemiology Umbilical metastases are uncommon, reportedly present in 1-3% of all intra-abdominal and/or pelvic malignancy 7. Clinical presentation ...
Article

Small bowel folds (differential)

Regular, smooth generalised thickening oedema congestive cardiac failure (CCF) hypoalbuminaemia lymphatic obstruction angioneurotic oedema infection radiation ischaemia haemorrhage anticoagulation or bleeding diathesis vasculitides IgA vasculitis (Henoch-Schonlein purpura) Buerger d...
Article

Small bowel imaging

Small bowel imaging aims at assessment of the disorders of small intestine. Imaging techniques barium follow through fluoroscopic enteroclysis conventional CT CT enteroclysis MR enteroclysis CT enterography MR enterography capsule endoscopy
Article

Small bowel ischaemia

Small bowel or mesenteric ischaemia may be a life-threatening condition, arising from any one of numerous causes of disturbance of the normal blood flow through the small bowel wall.  Pathology It can be divided into acute and chronic forms, with the main underlying aetiologies (each discussed...
Article

Soft-tissue sarcoma

Soft-tissue sarcomas are a heterogeneous group of malignant tumours of mesenchymal origin (sarcoma) that originate from the soft tissues rather than bone. They are classified on the basis of tissue seen on histology. The commoner sarcomas in the adult and paediatric population are listed below. ...
Article

Splenic amyloidosis

Splenic amyloidosis is rare as an isolated entity. Most often it is associated with either systemic amyloidosis or hepatic amyloidosis. Epidemiology In general, splenic involvement in amyloidosis is rather frequent (5-10% of cases 6,7). Clinical presentation Symptoms include abdominal mass a...
Article

Splenic calcification

Splenic calcifications can occur is various shapes and forms and can occur from a myriad of aetiological factors. The usual calcification observed in radiographs are the multiple, miliary form presenting numerous small rounded densities averaging from three to five millimetres in diameter where...
Article

Splenic cyst

Splenic epithelial cysts, also referred as splenic epidermoid cysts or primary splenic cysts, are unilocular fluid lesions with thin and smooth walls and no enhancement. They represent ~20% of cysts found in the spleen, and are usually an innocuous incidental imaging finding. Note that most (~8...
Article

Splenic haemangiomatosis

Splenic haemangiomatosis involves multiple, diffuse splenic haemangiomas replacing its entire parenchyma. It is a very rare entity. Pathology It can occur as a manifestation of systemic angiomatosis or, less commonly, confined to the spleen (diffuse isolated splenic haemangiomatosis). There is...
Article

Splenic lesions and anomalies

There are a number of splenic lesions and anomalies: Congenital anomalies accessory spleen wandering spleen asplenia polysplenia splenogonadal fusion retrorenal spleen Mass lesions Benign mass lesions splenic cyst (mnemonic) splenic pseudocyst splenic haemangioma: commonest benign sp...
Article

Splenomegaly

Splenomegaly refers to enlargement of the spleen. The upper limit of normal adult splenic length is traditionally cited at 12 cm, but lengths upwards of 14 cm can be seen in normal, taller males 7. Massive splenomegaly is variably defined, including when the spleen is 5 standard deviations abov...
Article

Spontaneous splenic rupture

Spontaneous splenic rupture (SSR) (or atraumatic splenic rupture) is rare, especially when compared to traumatic splenic rupture.  Pathology The pathogenesis of atraumatic splenic rupture is not well understood. Splenomegaly is present in almost all patients (~95%), although rupture of normal ...
Article

Sprue

Sprue is the collective term for the malabsorptive gastrointestinal enteropathies although it may be used to refer directly to tropical sprue. It is composed of two entities: tropical sprue non-tropical sprue / coeliac disease In each, the radiologic features are not sensitive enough to confi...
Article

Subdiaphragmatic free gas

Subdiaphragmatic free gas is one of the ways of detecting presence of free intraperitoneal gas (i.e. pneumoperitoneum). It is the presence of free, extraluminal gas in the anterior subhepatic space.  Radiographic features Plain radiograph Subdiaphragmatic free gas is well appreciated as the g...
Article

Terminal ileitis (differential)

The differential diagnosis for a terminal ileitis is quite extensive, and includes: inflammatory bowel disease Crohn disease (most common) backwash ileitis due to ulcerative colitis infectious colitis Yersinia spp.  Yersinia enterocolitica Yersinia pseudotuberculosis Salmonella spp. ​Sa...
Article

Tumours of the small intestine

The small intestine is rarely the site of malignant tumours, although it accounts for ~75% of the entire length of the GI tract and more than 90% of the mucosal surface. Approximately 40 different histologic tumour types have been described.  In this article, an overview will be given of the mo...
Article

Upper gastrointestinal bleeding (differential)

An upper gastrointestinal bleed usually refers to bleeding proximal to the ligament of Treitz. Pathology Causes peptic ulcer gastritis oesophagitis duodenitis Mallory-Weiss tear varices tumour vascular abnormality vascular ectasia angiodysplasia Dieulafoy lesion vascular malformati...
Article

Vertical-banded gastroplasty

Vertical-banded gastroplasty (VBG) is an older, purely restrictive procedure used to treat morbid obesity. Procedure It involves creating a small gastric pouch, based on the lesser curvature of the stomach (which is thicker and less resistant to stretching than the greater curvature), by using...
Article

Weight loss

A clinical presentation of weight loss is extremely common and often a source of marked anxiety for the patient. The commonest cause of unintentional weight loss (UWI) is gastrointestinal tract disease, and not malignancy. Terminology The published literature lacks a consistent definition of w...
Article

Widening of the presacral space (differential)

Widening of the presacral space is one of the diagnostic indicators of the diseases involving pelvic pathology and rectal involvement. It is ideally measured on barium studies at the level of S3/4 disc level on lateral radiographs and the normal value of the presacral space is <15 mm in adults.​...

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