Congenital tracheo-esophageal fistula is a congenital pathological communication between the trachea and esophagus.
Tracheo-esophageal fistula and esophageal atresia have a combined incidence of approximately 1 in 3500 live births 1-3,5. There is only a minimal hereditary/geneti...
The conjoint tendon, also known as Henle's ligament, forms when the medial fibers of the internal oblique aponeurosis unite with the deeper fibers of the transversus abdominis aponeurosis. The conjoint tendon then turns inferiorly and attaches onto the pubic crest and pecten pubis 1.
Corkscrew sign can refer to:
corkscrew sign (midgut volvulus)
corkscrew sign (tertiary esophageal contractions)
corkscrew sign (corkscrew cochlea)
The corkscrew sign describes the spiral appearance of the distal duodenum and proximal jejunum seen in midgut volvulus 1.
In patients with malrotation and volvulus, the distal duodenum and proximal jejunum do not cross the midline and instead pass in an inferior direction. These loops twist on ...
Cornual ectopic pregnancies are rare and represent a gestational sac within the cornua of a bicornuate or septate uterus.
Although sometimes interchangeably used with interstitial pregnancy, cornual pregnancy specifically refers to the presence of a gestational sac within a rudime...
The coronary ligament is a peritoneal ligament complex of the liver which encloses the bare area of the liver.
The coronary ligament is formed by the reflection of the peritoneum from the undersurface of the diaphragm onto the superior and posterior surfaces to the right lobe of ...
Corrosive esophagitis usually occurs from accidental or suicidal ingestion of caustic substances (e.g. lye, household cleaners, bleaches, washing soda), and is harmful to the esophagus due to their alkali medium. The stomach is not affected as the gastric acid can neutralize these substances, ho...
Cowden syndrome, also known as multiple hamartoma syndrome, is characterized by multiple hamartomas throughout the body and increased risk of several cancers.
Type 2 segmental Cowden syndrome is the association of Cowden syndrome with a Cowden nevus when it is considered a type of ...
The crescent in a doughnut sign refers to the transverse ultrasound appearance of intestinal intussusception, and is a variation of the target sign (which is also known as the doughnut sign)
The doughnut is formed by concentric alternating echogenic and hypoechogenic bands. The echogenic bands ...
Cricopharyngeal bar refers to the radiographic appearance of a prominent cricopharyngeus muscle contour on barium swallow.
The terms cricopharyngeal bar and cricopharyngeal muscle spasm/achalasia are often used synonymously but this is incorrect because studies have demonstrated th...
Cricopharyngeal muscle spasm is also known as cricopharyngeal achalasia, although some authors distinguish between these entities, and may present as a cause of dysphagia.
There is confusing use of the terms cricopharyngeal muscle spasm, cricopharyngeal achalasia and cricopharyngea...
Crohn disease, also known as regional enteritis, is an idiopathic inflammatory bowel disease characterized by widespread discontinuous gastrointestinal tract inflammation. The terminal ileum and proximal colon are most often affected. Extraintestinal disease is common.
A mnemonic to remember the radiological features of Crohn disease is:
C: cobblestone appearance of mucosa
R: rose-thorn ulcers
O: obstruction of bowel
H: hyperplasia of mesenteric lymph nodes
N: narrowing of intestinal lumen
S: skip lesions
Due to the overlap in the clinical presentation of Crohn disease (CD) and ulcerative colitis (UC), imaging often has a role to play in distinguishing the two. Distinguishing features include:
CD: small bowel 70-80%, only 15-20% have only colonic involvement
UC: rectal involveme...
Cronkhite-Canada syndrome is a type of non-neoplastic, non-hereditary hamartomatous polyposis syndrome characterized by rash, alopecia, and watery diarrhea.
There is a recognized male predilection with 3:2 male:female. Patients typically are middle age (50-60 years of age) 1. 75% ...
A crus (plural: crura) is an anatomical term used for a structure which resembles a leg.
crus (internal capsule)
crus (semicircular duct)
Cryptococcomas are a rare complication of infection by the Cryptococcus genus of invasive fungi, where a discrete, encapsulated lesion of immune infiltrates and pathogen forms. Cryptococcus gattii is most often isolated but Cryptococcus neoformans may also form cryptococcomas.
This is a basic article for medical students and other non-radiologists
CT abdomen is an increasingly common investigation that is used to help make diagnoses of a broad range of pathologies. A CT abdomen in its simplest form is a CT from diaphragm to symphysis pubis performed 60 seconds after ...
Multi-slice CT angiography of the splanchnic vessels is a powerful minimally invasive technique for evaluation of the splanchnic vascular system.
The actual procedure will vary depending on institutional protocol/guidelines but below is a typical description 2, 4:
The interpretation of CT colonography can sometimes be difficult because of pitfalls, which may be a source of false negative and false positive findings. When suboptimal CT colonography techniques are applied, the number and severity of interpretive pitfalls can rapidly multiply. However, when ...
CT Colonography Reporting and Data System (C-RADS) is a method devised to standardize CT colonography reporting.
It primarily classifies abnormalities into colonic (C) and extra-colonic (E).
C0: inadequate study
C1: normal colon/benign lesion: routine s...
Enteric contrast media can be given to patients before their CT to improve its diagnostic accuracy. Historically, a combination of oral and intravenous contrast media were always given prior to a CT abdomen. Contemporaneously, improved CT scanners mean that oral contrast agents are no longer rou...
Computed tomographic (CT) enteroclysis refers to a hybrid technique that combines the methods of fluoroscopic intubation-infusion small bowel examinations with that of abdominal CT.
CT enteroclysis is complementary to capsule endoscopy in the elective investigation of small-bowel d...
Computed tomographic (CT) enterography is a non-invasive technique for the diagnosis of small bowel disorders.
CT enterography, similarly to MRI enterography, is most commonly used to evaluate patients with Crohn disease where it is used for assessment of the primary disease and an...
CT esophagography is a CT study designed to primarily evaluate the esophagus, particularly in the situation of esophageal trauma and potential perforation. It has been developed partly as an alternative to fluoroscopic barium swallow evaluation in this situation.
CT hypoperfusion complex refers to the predominantly abdominal imaging features that occur in the context of profound hypotension. Multiple abdominal organs can display atypical appearances not related to the initial trauma but reflect alterations in perfusion secondary to hypovolemia which affe...
CT peritoneography is an examination used to assess difficulties with peritoneal dialysis.
Recurrent peritonitis with difficulty with fluid exchange, abdominal wall or genital soft tissue edema, localized bulging of the abdomen, and poor ultrafiltration.
CT polytrauma/multitrauma, also called trauma CT, whole body CT (WBCT) or panscan, is an increasingly used investigation in patients with multiple injuries sustained after significant trauma.
Clinical assessment and mechanism of injury may underestimate injury severity by 30% 8. There is some e...
The CT severity index (CTSI) is based on findings from an enhanced CT scan to assess the severity of acute pancreatitis. The severity of acute pancreatitis CT findings has been found to correlate well with clinical indices of severity.
The CT severity index sums two scores:
Balthazar score: g...
The cupola sign is seen on a supine chest/abdominal radiograph in the presence of pneumoperitoneum.
It refers to non-dependent gas that rises within the abdominal cavity of the supine patient to accumulate underneath the central tendon of the diaphragm in the midline. It is seen as lucency ove...
The cystic duct connects the neck of the gallbladder to the common hepatic duct (CHD), draining bile to and from the biliary tree.
The confluence of the cystic duct and the common hepatic duct forms the common bile duct (CBD). The cystic duct is approximately 2-3 cm long and 2-3 ...
Cystic fibrosis (CF), also called mucoviscidosis, is an autosomal recessive genetic disease that affects the exocrine function of the lungs, liver, pancreas, small bowel, sweat glands, and the male genital system 11. resulting in progressive disability and multisystem failure. This article is a ...
Abdominal manifestations in cystic fibrosis (CF) are common, varied and nearly all organ systems can be affected, and it should be remembered that only 39% of patients with cystic fibrosis have pulmonary symptoms as their sole complaint 1. Not only that, but 7% of cystic fibrosis patients do not...
The differential for cystic lesions of the pancreas includes:
intraductal papillary mucinous neoplasm (IPMN)
serous cystadenoma uncommonly uni/macrolocular
simple pancreatic cyst
pancreatic cysts occur in association with
von Hippel Lindau syndrome
A mnemonic for causes of cystic lesions in the spleen is:
Cystic or necrotic appearing lymph nodes can be caused by a number of infectious, inflammatory or malignant conditions:
squamous cell carcinoma metastases
plasmacytoid T-cell leukemia
acute myeloid leukemia
herpes simplex lymphadenit...
Cystic retroperitoneal lesions can carry a relatively broad differential, which includes:
retroperitoneal lymphatic malformation
retroperitoneal mucinous cystadenoma
retroperitoneal cystic teratoma
retroperitoenal cystic mesothelioma
pseudomyxoma retroperitonei with cystic change
De Garengeot hernias (alternative plural: herniae) are femoral hernias that contain the appendix.
It is not to be confused with Amyand hernia, which is an appendix-containing inguinal hernia.
It is a rare phenomenon, with only 1% of all femoral hernias containing the appendix (an...
Degloving bowel injuries are a rare type of bowel and mesenteric injury only being described a handful of times in the literature 1-5. In these injuries the bowel is stripped of its mesentery and muscle, leaving a "mucosal tube" 2,3. Perforation may or may not be present.
Degloving injuries can refer to a number of conditions:
degloving soft tissue injury
Morel-Lavallée lesion (closed degloving soft tissue injury)
intramuscular degloving injury
degloving bowel injury
Dehiscence is a general term referring to 'splitting open' and is used in a variety of contexts in medicine generally and radiology more specifically.
The two most common usages are:
splitting open of a wound (e.g. sternal dehiscence)
loss of bone separating one structure from another (e.g. ...
Dental caries are cavities in teeth ('caries' is both the singular and plural form). They are very common and can lead to serious morbidity.
Tooth decay is asymptomatic in its early stages. Once the enamel has been breached and the dentin is exposed then people may exper...
The dependent viscera sign is one of the signs of diaphragmatic rupture on axial CT or MR images, where herniated viscera lie against the posterior thoracic wall in a dependent position, as they are no longer supported by the diaphragm.
collar sign (or hourglass sign)
The descending colon is the continuation of the transverse colon after the left colic flexure, where the colon loses its mesentery.
The descending colon measures up to 25 cm in length and is secondarily retroperitoneal. It descends down attached to the left posterior abdominal w...
Desmoplastic small round cell tumors of the peritoneum are a rare and highly aggressive primary peritoneal malignancy.
Desmoplastic small round cell tumor is usually seen in young adolescents and have a male predominance with a mean survival of 2-3 years.
Diabetes mellitus (DM) often referred to simply as diabetes, is a group of metabolic conditions characterized by hyperglycemia.
These conditions should not be confused with diabetes insipidus which is clinically distinct and not related to hyperglycemia.
If a patient with diabete...
The diaphragm is the dome-shaped muscle that separates the thoracic cavity from the abdominal cavity, enclosing the inferior thoracic aperture.
On chest imaging, in particular chest radiography, an imaginary anteroposterior halfway line divides the diaphragm into two, forming the l...
Diaphragmatic rupture often results from blunt abdominal trauma. The mechanism of injury is typically a motor-vehicle collision.
Given that the most common mechanism is motor vehicle collisions, it is perhaps unsurprising that young men are most frequently affected. The estimated ...
Dieulafoy lesions (also known as exulceratio simplex) are uncommon but important causes of acute upper gastrointestinal bleeding. A Dieulafoy lesion is characterized by a dilated tortuous submucosal artery that erodes overlying gastrointestinal mucosa most commonly found in the stomach.
Differential diagnosis of hepatic nodule in cirrhotic liver include regenerative liver nodules, dysplastic liver nodules, and hepatocellular carcinoma (HCC), all represent a spectrum of disease ranging from non-neoplastic reparative process (regenerative) to nuclear atypia (dysplastic) to typica...
Diffuse colonic nodularity on barium enema or CT colonography has a range of possible etiologies:
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)
Diffuse/distal esophageal spasm (DOS) is a motility disorder of the esophagus. On barium swallow, diffuse esophageal spasm may appear as a corkscrew or rosary bead esophagus, but this is uncommon. Manometry is the gold-standard diagnostic test.
Diffuse esophageal spasm differs from hypercontrac...
Diffuse or disseminated peritoneal leiomyomatosis, also known as leiomyomatosis peritonealis disseminata, is an exceedingly rare benign disorder characterized by multiple vascular leiomyomas growing along the submesothelial tissues of the abdominopelvic peritoneum.
It is usually d...
Diffuse small bowel disease may be caused by a number of conditions may be generalized multisystem disorders or conditions that effect the bowel in a global fashion:
A direct inguinal hernia (alternative plural: herniae) is a type of groin herniation, that arises from protrusion of abdominal viscera through a weakness of the posterior wall of the inguinal canal medial to the inferior epigastric vessels, specifically through Hesselbach's triangle.
This type ...
Disconnected pancreatic duct syndrome, also referred only as disconnected pancreatic duct, refers to the symptoms and complications due to the complete discontinuity of the main pancreatic duct between segments of viable secreting pancreatic tissue and the duodenum, usually seen as a sequela of ...
Discrete colonic ulcerations are nonspecific findings, and can be due to:
Distal intestinal obstruction syndrome (DIOS) is one the of many abdominal manifestations of cystic fibrosis. In older children or young adults with cystic fibrosis, the distal small bowel may become obstructed with a mucofaeculent material in the distal ileum and right colon.
Diversion colitis, also known as diversional colitis, describes non-specific inflammation of segments of colon and/or rectum which have been surgically diverted from the fecal stream after colostomy or ileostomy.
A similar condition, diversion pouchitis, manifesting after formation of continent...
Diverticular disease generally refers to phenomenon involving acquired diverticula along the lower gastrointestinal tract. It covers a range of pathologies and may account for a variety of presentations. Diverticulosis is largely asymptomatic however 4% of individuals with diverticula develop di...
This is a basic article for medical students and other non-radiologists
Diverticulitis is one of the presentations of diverticular disease and is most often a complication of colonic diverticulosis. Differentiating one from the other is critical since uncomplicated diverticulosis is mostly asym...
Diverticula are outpouchings of a hollow viscus and can be either true or false.
Occasionally a diverticulum is used in a more general sense to mean the outpouching of other anatomical structures, e.g. frontal intersinus septal cells are hypothesized to form as diverticula from the frontal sinu...
The dog ear sign represents the presence of fluid or blood in the pelvic peritoneal recess on a supine abdominal radiograph. The appearance of the sign comes from a convex soft-tissue density representing fluid or blood in the lateral pelvic peritoneal recess separated from the bladder by a thin...
The doge cap sign, also referred to as Morison pouch sign, is a radiographic sign of pneumoperitoneum. It presents as a triangular-shaped gas lucency or can be crescent shaped, or semicircular is usually bound by the 11th rib in the right upper quadrant on abdominal radiographs due to air in the...
Agenesis of the dorsal pancreas is an extremely rare congenital pancreatic anomaly.
While complete agenesis of the dorsal pancreas is extremely rare, partial agenesis of the dorsal pancreas is thought to be more common than ventral pancreatic agenesis 4.
While many pati...
Double barrel sign is an imaging appearance of two lumens adjacent to each other.
It can be seen in:
dilated bile duct adjacent to portal vein
double barrel aorta: aortic dissection
double barrel esophagus: esophageal dissection
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.
Causes include 1,2:
The double contrast barium enema is rapidly being replaced by CT colonography, but remains in some centers for:
the detection of polyps and colorectal cancer
follow up screening for postoperative colorectal cancer
evaluation of diverticular disease
investigation of non-sp...
Double contrast barium enema (DCBE) technique is a method of imaging the colon with fluoroscopy. "Double contrast" refers to imaging with the positive contrast of barium sulfate contrast medium (rarely water-soluble iodinated contrast) as well as with the negative contrast of gas (CO2 preferable...
The double duct sign refers to the presence of simultaneous dilatation of the common bile and pancreatic ducts. Being an anatomical sign it can be seen on all modalities that can visualize the region, including: MRI, CT, ultrasound and endoscopic retrograde cholangiopancreatography (ERCP).
The double track sign is a radiological sign described in pyloric stenosis on various imaging modalities.
Double streaks of barium passing through the narrow pylorus 1.
On fluid aided real-time examination, the pyloric fluid is compressed into smaller tracks as it is...
The doughnut sign can refer to a variety of different signs:
doughnut sign (bone scan)
doughnut sign (bowel)
crescent in a doughnut sign (bowel)
doughnut sign (chest)
doughnut sign (orbit)
Downhill esophageal varices are an uncommon type of esophageal varices associated with superior vena cava (SVC) obstruction.
Downhill oesophagal varices are less frequently seen. It is seen in less than 0.5% of routine upper endoscopies. Most common etiology is superior vena obstr...
Down syndrome (or trisomy 21) is the most common trisomy and also the commonest chromosomal disorder. It is a major cause of intellectual disability, and also has numerous multisystem manifestations.
The approximate worldwide incidence is approximately 1 in 800 live births 15. The...
Retained appendicoliths, also called dropped or slipped appendicoliths, are appendicoliths that have been inadvertently left inside the peritoneal cavity following appendectomy.
Patients may be asymptomatic in some cases. Other cases may present with infective symptoms du...
Duct penetrating sign is a radiographic sign that can be useful in differentiating between focal pancreatitis (inflammatory pancreatic mass) from pancreatic carcinoma.
A positive sign is when a mass is penetrated by an unobstructed pancreatic duct; this makes focal pancreatitis the most likely ...
The Dukes staging system is a classification system for colorectal cancer. This system is now mainly of historical interest as it has largely been replaced by the TNM staging system. It is not recommended for clinical practice.
Dukes A: invasion into but not through the bowel wall (90% 5 year s...
Duodenal adenocarcinoma is the most common primary malignancy of the duodenum.
Adenocarcinoma is the most common primary malignant neoplasm of the duodenum. It represents 0.3% of all gastrointestinal malignancies and accounts for 50-70% of small bowel adenocarcinomas occurring ei...
Duodenal atresia results from a congenital malformation of the duodenum and requires prompt correction in the neonatal period. It is considered to be one of the commonest causes of a fetal bowel obstruction.
The prevalence of duodenal atresia is ~1 in 5,000-10,000 newborns, and th...
The duodenal bulb refers to a proximal-most portion of the duodenum closest to the stomach and for most of the D1 segment of the duodenum. It usually has a length of about 5 cm. It commences at the gastric pylorus and ends at the neck of the gallbladder. It is located posterior to the liver and...
Duodenal diverticulitis (plural diverticulitides) is a rare, inflammatory complication of duodenal diverticula.
While the vast majority of patients are asymptomatic, patients with diverticulitis usually present with epigastric pain, nausea and vomiting.
Duodenal diverticula are outpouchings from the duodenal wall (intraluminal diverticulum discussed separately). They may result from mucosal prolapse or the prolapse of the entire duodenal wall and can be found at any point in the duodenum although are by far most commonly located along the media...
Duodenal filling defects may be caused by a wide variety of duodenal pathology which may be divided by their location and pathological process.
common bile duct impression
Note: please refer to duodenal mucosal nodular fill...
Duodenal hematoma results in hematoma formation in the duodenal wall. It may occur as a result of blunt abdominal trauma, non-accidental injury to children and spontaneously in anti-coagulated patients.
Distinction must be made from duodenal perforation since the latter will require immediate s...
A duodenal–jejunal bypass liner (DJBL), also known as a duodenal–jejunal bypass sleeve device or EndoBarrier™ is being trialled as a new technique, as an alternative to more 'traditional' gastric bypass surgeries 1,2. The basic principle is that the sleeve is endoscopically-inserted into the duo...
A duodenal stricture refers to a segment of narrowing involving the duodenum. They can occur from a range of benign infective - inflammatory to malignant etiology. They can contribute to gastric outlet obstruction.
The duodenal switch procedure is a form of biliopancreatic diversion which is often done as a obesity reduction surgery.
It has a restrictive portion and malabsorptive portion
restrictive portion: involves removal of approximately 70% of the stomach (along the greater curvature) and most of th...
Duodenal varices is the dilatation of the posterior superior pancreaticoduodenal vein secondary to portal hypertension. They are much less common than esophageal, rectal or fundal varices, but may be associated with them.
Lobulated filling defects are best de...
A duodenal web, diaphragm or intraluminal diverticulum refers to a complete or incomplete obstruction at the duodenum due to a membranous web or intraluminal diverticulum. There is usually a small aperture at the center differentiating this from duodenal atresia.
Although they ar...
Duodenitis is a term given to inflammation of the duodenum.
A duodenitis can result from both intrinsic processes within the duodenum as well as from processes occuring outside the duodendum. It can occur from infective as well as non-infective inflammatory processes.
The duodenojejunal (DJ) flexure or junction is the anatomical border between the duodenum and the jejunum.
The DJ flexure is located anterolateral to the aorta at the level of the upper border of the second lumbar vertebra. It makes a sharp turn anteroinferiorly to become the jej...
The duodenum is the first part of the small intestine and is the continuation of the stomach.
The duodenum is a 20-30 cm C-shaped hollow viscus predominantly on the right side of the vertebral column. It lies at the level of L1-3 and the convexity of the duodenum (called the duod...
Duplex appendix is a rare anomaly of the appendix and is usually discovered incidentally during surgery for appendicitis.
Duplication of the vermiform appendix is extremely rare. It is found in only 1 in 25,000 patients (incidence ~0.004%) operated on for acute appendicitis. Altho...