This is a basic article for medical students and other non-radiologists
Nasogastric (NG) tube position on chest x-ray should be assessed following initial placement and on subsequent radiographs.
This is a summary article; we have a more in-depth reference article NGT.
Necrotizing enterocolitis (NEC) is the most common gastrointestinal condition in premature neonates. It is characterized by inflammation, ischemia, and permeability of the neonatal bowel wall to bacteria. It is potentially life-threatening with significant associated morbidity 1.
Necrotizing enterocolitis (NEC) can be staged into three groups, to guide appropriate treatment based on the work of Bell et al. 1. In general, stage I and II are managed medically whereas stage III is managed surgically.
lethargy, temperature instability, apnea, bradyc...
Necrotizing pancreatitis (NP) represents a severe form of acute pancreatitis. It is considered a subtype of acute pancreatitis as necrosis usually tends to occur early, within the first 24-48 hours, but can also rarely occur with subacute forms.
A key feature is a significant amount of pancreat...
AP supine radiograph for neonates is a mobile examination performed on the neonatal unit. It can be taken as a standalone projection or as part of a series including a left lateral decubitus x-ray in cases of suspected perforation.
the patient is supine, lying on their back i...
Neonatal appendicitis is rare, presumably in part due to the short funnel shape of the appendix at that age. Symptoms are non-specific and may mimic necrotizing enterocolitis.
The causes of neonatal pneumoperitoneum are different from adult pneumoperitoneum and include:
perforated hollow viscus
necrotizing enterocolitis (NEC): most common
meconium ileus in cystic fibrosis
intestinal atresia or web
peptic ulcer disease
There are a number of neoplasms that can involve the vermiform appendix, some of which are peculiar to this site.
Tumors involving the appendix have been found in only about 1% of all appendectomy specimens 9. Epithelial neoplasms and neuroendocrine tumors represent the vast major...
Neuhauser sign refers to a soap bubble appearance seen in the distal ileum in cases of meconium ileus, related to the air mixed with meconium. It may be seen with barium enema if contrast passes beyond the ileocecal valve or with small-bowel follow-through.
Although classically described with m...
Niacin (vitamin B3) deficiency, also known as pellagra, is a multisystem disease which involves the skin, gastrointestinal tract and central nervous system.
It use to be widespread until the early twenty century, but after fortification of flour with niacin it was practically era...
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
Non-neoplastic solid lesions of the pancreas are conditions which may mimic pancreatic neoplasms on imaging. They include:
intrapancreatic accessory spleen
peripancreatic lymph node
Non-specific esophageal motility disorder (NSMD) is one of the esophageal dysmotility disorders. It is used to describe patients with esophageal dysmotility that do not meet diagnostic criteria for other esophageal motility disorders.
Patients may be asymptomatic or pres...
This article lists examples of normal imaging of the gastrointestinal tract and surrounding structures, divided by modality.
example 1: abdominal film
example 2: erect and supine
example 3, example 4: pediatric
example 5: young adult male
example 1, example...
In the premultidetector CT era, mesenteric lymph nodes (often shortened to mesenteric nodes) were only really appreciated when enlarged. Following the advent of routine volume acquisition CT (and especially coronal reformats) lymph nodes in the mesentery are commonly seen in normal individuals, ...
There are a number of normal esophageal contours or impressions that are encountered when performing a barium swallow. It is important to be able to differentiate normal contours and their variants, as well as contours that may indicate disease. Below is a list of anatomical structures that may ...
Normal postmortem changes in the gastrointestinal tract refers to the normal changes that can be expected to be seen in the gastrointestinal tract on post-mortem imaging.
The following changes may be present in the abdomen and gastrointestinal tract 1:
The northern exposure sign has been described as a high specificity sign in sigmoid volvulus. On a supine abdominal radiograph, the apex of the sigmoid volvulus is seen above (cranial to) the transverse colon.
The nutcracker phenomenon (NCP), also known as left renal vein entrapment refers to a situation of impeded outflow from the left renal vein (LRV) into the inferior vena cava (IVC) as a result of compression and is often accompanied by demonstrable lateral (hilar) dilatation and mesoaortic narrow...
This is a basic article for medical students and other non-radiologists
Obstructive jaundice represents a set of conditions that cause jaundice by obstructing the flow of bile into the duodenum anywhere along the intrahepatic or extrahepatic biliary tree.
This is a summary a...
Obturator hernias are characterized by bowel herniating between the obturator and the pectineus muscles. They are a rare type of abdominal hernia and can be very difficult to diagnose clinically.
Typically obturator hernias occur in older women 2,3 or patients with chronically rai...
Octreotide scintigraphy uses 111In-labeled octreotide which is a somatostatin analog; it is also known as an OctreoscanTM, a brand name for 111In-labeled pentetreotide; pentetreotide is a DTPA-conjugated form of octreotide, originally manufactured by Mallinckrodt Nuclear Medicine LLC, which now ...
Esophageal atresia refers to an absence in the continuity of the esophagus due to an inappropriate division of the primitive foregut into the trachea and esophagus. This is the most common congenital anomaly of the esophagus.
It is thought to occur in ~1:3,000-4,500 live births 3...
Esophageal atresia is closely related to tracheo-esophageal fistula and can be divided into1:
type A: isolated esophageal atresia (8%)
type B: proximal fistula with distal atresia (1%)
type C: proximal atresia with distal fistula (85%)
type D: double fistula with intervening atresia (1%)
Esophageal bronchus, a.k.a. communicating bronchopulmonary foregut malformation, refers to the rare occurrence where a bronchus arises directly from the esophagus.
It is more common in females with a M:F of 1:2 2.
Esophageal bronchi may be the main bronchus, which...
This is a basic article for medical students and other non-radiologists
Esophageal cancer is a relatively uncommon tumor that occurs within the esophagus of affected individuals. Patients present with symptoms of increasing dysphagia that progress from solid foods to liquids.
Esophageal carcinoma is relatively uncommon. It tends to present with increasing dysphagia, initially to solids and progressing to liquids as the tumor increases in size, obstructing the lumen of the esophagus.
Esophageal cancer is responsible for <1% of all cancers and 4-10% of a...
Esophageal diverticula are sac or pouch projections arising from the esophagus.
They can occur in all ages but more frequent in adults and elderly people.
Esophageal diverticula are either:
true diverticula: include all esophageal layers
false diverticula: contain on...
Duplication of the esophagus has a range of macroscopic appearances from complete (very rare) to partial cystic duplication (esophageal duplication cyst). It is the second most common gastrointestinal tract duplication after that of the ileum.
A complete duplication is a rare malf...
Esophageal duplication cysts are a type of congenital foregut duplication cyst.
Less common compared to other foregut duplication cysts. There may be an increased male predilection 5.
Patients are generally asymptomatic but may complain of dysphagia due to ...
Esophageal dysmotility refers to the pathological disruption of the normal sequential and coordinated muscle motion of the esophagus 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 cau...
Esophageal fibrovascular polyps are benign intraluminal submucosal pedunculated tumors that can grow significantly and cause dysphagia symptoms. They usually occur in the upper third of the esophagus, at the level of the upper esophageal sphincter.
They were previously denominated...
Esophageal food impaction (or steakhouse syndrome) refers to a food bolus acutely obstructing the esophagus.
The main symptom is usually acute dysphagia.
Depending on the composition of the ingested content, the bolus may be visib...
The esophageal hiatus is the opening in the diaphragm through which the esophagus passes from the thoracic to abdominal cavity. It is one of three apertures in the diaphragm and is located in the right crus.
It is situated in the muscular part of the diaphragm at the level of T10 and is ellipti...
Esophageal intubation refers to the incorrect placement of an endotracheal tube in the esophagus. Within minutes its consequences can be catastrophic with the seriousness of its outcome depending largely on the timeliness of its diagnosis.
Accidental esophageal intubation can happ...
Esophageal leiomyoma is a benign smooth muscle neoplasm of the esophagus. It is the most common benign tumor of the esophagus.
It is most frequently presents in young and middle age groups (20-50 years). The overall incidence is around 8-43 per 10,000 autopsy series 4.
Esophageal leiomyomatosis is rare benign condition.
It usually presents at childhood. There is a recognized increased female predilection.
It is considered a hamartomatous condition and is associated with abnormal diffuse proliferation of smooth muscle fibers in distal...
Esophageal leiomyosarcoma is a rare malignant tumor of the esophagus of smooth muscle origin.
Esophageal leiomyosarcoma is a rare disease. Since first described in 1905, there have been over 164 cases described in the literature.
Esophageal lipomas (or lipomata) are rare fat-containing esophageal lesions.
They may account for approximately 0.4% of the benign tumors of the alimentary tract 1. There may be greater male predilection. The average age of presentation is around 50 years.
A mnemonic to remember the causes of an esophageal mass is:
CALL the MVP
Esophageal myotomy (or Heller myotomy) is a procedure that can be performed to treat a lower esophageal sphincter that fails to relax (e.g. achalasia). The procedure involves a longitudinal incision of the distal esophageal musculature to break the sphincter tone.
A fundoplication wrap can be p...
Esophageal perforation is a rare but serious medical emergency with a very high mortality rate, especially if the diagnosis is delayed.
Most patients are in their sixties with a slight male predominance 5.
If a perforation is not detected during the proced...
Esophageal intramural pseudodiverticulosis is an uncommon condition in which there are numerous small outpouchings within the esophageal wall.
It is a rare condition, found in <1% of oesophagrams. It may occur at any age, but is more common between 50 and 70 years. There is a slig...
Esophageal squamous papilloma is an uncommon finding on esophagography (barium swallow). It is a benign lesion, but it is difficult to differentiate it from osophageal carcinoma on esophagography and the diagnosis is usually made with endoscopic biopsy.
Esophageal stents are a treatment option in patients with esophageal strictures. It is most commonly used for symptomatic relief in those with dysphagia secondary to malignancy. The stent is typically covered in nature and inserted endoscopically or fluoroscopically. The distal esophagus is the ...
Esophageal stricture refers to any persistent intrinsic narrowing of the esophagus.
The most common causes are fibrosis induced by inflammatory and neoplastic processes. Because radiographic findings are not reliable in differentiating benign from malignant strictures, all...
Esophageal varices describe dilated submucosal veins of the esophagus, and are an important portosystemic collateral pathway. They are considered distinct from gastric varices, which are less common.
Esophageal varices are present in ~50% of patients with portal hypertension 1,2. ...
Esophageal webs refer to an esophageal constriction caused by a thin mucosal membrane projecting into the lumen.
Esophageal webs tend to affect middle-aged females.
Patients are usually asymptomatic and the finding may be incidental and unimportant. However...
Esophagectomy is a surgical procedure that involves excision of the majority of the esophagus and part of the proximal stomach, usually as a treatment for esophageal carcinoma or carcinoma of the gastric cardia, although benign conditions (e.g. stricture) may - rarely - be treated with this appr...
Esophagitis refers to inflammation of the esophagus. It can arise from a range of causes which include:
acute phlegmonous esophagitis
non infective esophagitis
The esophagus is a muscular tube that conveys food and fluids from the pharynx to the stomach.
The esophagus is 23-37 cm long with a diameter of 1-2 cm and is divided into three parts:
cervical: continuous with the hypopharynx, commences at the lower border of cricoid cartilage ...
The omega sign can refer to a number of different anatomical structures or signs:
omega sign (epiglottitis)
omega sign (hand bump on the precentral gyrus)
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.
The most common cause is metasta...
Omental infarction is a rare cause of acute abdomen resulting from vascular compromise of the greater omentum. This condition has a non-specific clinical presentation and is usually managed conservatively. The term along with epiploic appendagitis is grouped under the broader umbrella term intra...
Omental torsion is defined as a twist of the omentum along its long axis with consequent impeding of its vascularity that may mimic acute abdomen 1.
Omental torsion is a rare cause of acute abdominal pain that occurs in the third to fifth decade of life with slight male predomina...
An omentum is a double layer of peritoneum that attaches the stomach to another viscus:
the greater omentum hangs from the greater curvature of the stomach like an apron
the lesser omentum attaches the lesser curvature of the stomach to the liver superiorly
Omphaloceles, or exomphalos, are congenital midline abdominal wall defects at the base of the umbilical cord insertion, with herniation of gut (or occasionally other content) out of the fetal abdomen.
The estimated occurrence can be up to 1:4000 of live births 3.
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.
Oral cholecystography was a procedure used to image the gallbladder, now largely superseded by ultrasound and MRCP. It was first described by Graham et. al in 1925, using sodium tetraiodophenolphthalein.
Although rarely performed now, more modern techniques used other cholegraphic agents such ...
A useful mnemonic to help remember the order of structures in the porta hepatis from anterior to posterior is:
D: ducts (right and left hepatic duct branches)
A: arteries (right and left hepatic artery branches)
V: vein (portal vein)
E: epiploic foramen (of Winslow)
Fecal impaction is a sequela of long term constipation, whereby a hard fecal mass in the rectum prevents defecation from occurring. The resultant rectal dilatation leads to smooth muscle relaxation of the internal anal sphincter. Concurrently the obstructing stool mass leads to increased secreti...
The AP supine abdominal radiograph is a routine view when imaging the pediatric abdomen. This view may be taken alongside the PA erect and lateral decubitus views. As radiation protection is an essential consideration in pediatrics, some departmental protocols may only perform one view (either t...
There are a number of pain rating scales used by clinicians and researchers to gauge the severity of patients' pain. Commonly used methods:
pain numeric rating scale (NRS/NPRS)
visual analog scale (VAS)
verbal rating scale (VRS)
faces pain scale-revised (FPS-R)
Pain numeric rating scale
The pancreas (plural: pancreata) is a retroperitoneal organ that has both endocrine and exocrine functions: it is involved in the production of hormones (insulin, glucagon and somatostatin), and also involved in digestion by its production and secretion of pancreatic juice.
A pancreas transplant is a procedure in which a donor pancreas is transplanted to a recipient. The donor pancreas is typically cadaveric, but may rarely be a segment from a living donor 1. The transplant is meant to establish normoglycemia in patients with diabetes mellitus, typically type 1, th...
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 aging, obesity and end-stage chronic pancreatitis.
It occurs principally with fatty replacement of the pancreas (pancreatic ...
Pancreatic calcifications can arise from many etiologies.
Punctate intraductal calcifications
alcoholic pancreatitis (20-40%) 2
intraductal, numerous, small, irregular
preponderant cause of diffuse pancreatic intraductal calcification
gallstone pancreatitis (2%) 2
Staging of pancreatic ductal adenocarcinoma is traditionally done according to American Joint Committee on Cancer (AJCC) / Union for International Cancer Control (IUCC) TNM system. In 2017 new edition (8th edition) AJCC published with some major changes; now exocrine and endocrine tumors of the...
The ductal embryology of the pancreas is moderately complicated, leading to a number of anatomical variants of the pancreatic ducts, many of which are clinically significant.
The normal arrangement is for the entire pancreas to be drained via a single duct, to the ampulla of Vate...
Pancreatic intraductal tubulopapillary neoplasms (ITPNs) are rare variants of intraductal papillary neoplasms. Unlike an IPMN, an ITPN does not produce mucin.
Incidence/prevalence is unclear. Small series show an even male:female distribution and an average age of presentation of ...
Pancreatic intraepithelial neoplasia (PanIN) is a precursor lesion to pancreatic ductal adenocarcinoma, but the frequency at which this transition occurs is unknown.
Increasing incidence with age 1. Risk factors:
pancreatic lipomatosis 3
Mostly flat lesions ...
Pancreatic lipomas are uncommon mesenchymal tumors of the pancreas.
Rarely symptomatic, they are most often detected incidentally on cross-sectional imaging for another purpose. If they do cause symptoms, it will typically be those related to regional mass effect from the...
Pancreatic lipomatosis refers to fat accumulation in the pancreatic parenchyma. This finding is most often associated with obesity and aging.
It tends to be the commonest pathological condition involving the pancreas. The condition may occasionally simulate a mass-like lesion particularly when...
Pancreatic lymphangiomas are benign lesions that are often found incidentally during cross-sectional imaging for another reason.
For a broader discussion, please refer to the parental article on lymphangioma.
More common in adults (in contrast to lymphangiomas in the he...
Pancreatic lymphoma is most commonly a B-cell sub-type of non-Hodgkin lymphoma.
Pancreatic lymphoma is typically seen in middle-aged patients with a mean age of around 55 years old and is more common in immunocompromised patients.
Symptoms are often non-spe...
Pancreatic mesenchymal neoplasms (or pancreatic nonepithelial neoplasms) are a group of rare pancreatic neoplasms that arise from the structural elements of the pancreas (nerves, fat, lymph), rather than from the exocrine or endocrine cells of the pancreas. Neoplasms from exocrine and endocrine ...
There are numerous primary pancreatic neoplasms, in part due to the mixed endocrine and exocrine components.
Classification based on function
exocrine: ~99% of all primary pancreatic neoplasms
pancreatic ductal adenocarcinoma ~90-95%
intraductal papillary muc...
Pancreatic neurofibromas are rare nonepithelial neoplasms of the pancreas. They are similar to neurofibromas found elsewhere in the body, and are associated with neurofibromatosis type I.
If they do cause symptoms, it will typically be those related to regional mass effe...
The pancreaticoduodenal veins accompany their corresponding arteries and act to drain the head of the pancreas and duodenum.
There are four small pancreaticoduodenal veins:
posterior superior pancreaticoduodenal vein
anterior superior pancreaticoduodenal vein
Pancreatico-pleural fistulas are a rare complication of acute or chronic pancreatitis whereby enzymatic pancreatic fluid, either from a pancreatic pseudocyst or directly from a disrupted duct, dissects into the pleural cavity. Pancreaticopleural fistulas may also develop in the setting of trauma...
Pancreatic perivascular epithelioid cell tumors (or "Pancreatic PEComas") are a subtype of the larger family of PEComas. Pancreatic PEComas are very rare with <20 cases described.
More common in adults (in contrast to lymphangiomas in the head and neck, which are more com...
Pancreatic pseudocysts are common sequelae of acute pancreatitis or chronic pancreatitis, and the most common cystic lesion of the pancreas. They are important both in terms of management and differentiation from other cystic processes or masses in this region.
The following are th...
A number of pancreatic injury grading systems have been proposed.
American Association for the Surgery of Trauma (AAST)
grade 1: hematoma with minor contusion/laceration but without duct injury
grade 2: major contusion/laceration but without duct injury
grade 3: distal lacer...
Pancreatic ultrasound can be used to assess for pancreatic malignancy, pancreatitis and its complications, as well as for other pancreatic pathology.
Fast the patient to reduce interference from overlying bowel gas, which may otherwise make visualization difficult.
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, etiological agent or associated pathology.
interstitial edematous pancreatitis
Pancreatoblastomas are rare pediatric tumors of the pancreas. However, they are the most common pancreatic neoplasm of childhood and are often associated with a raised alpha-fetoprotein.
There is slight male predilection. Usually occurs in the first decade of life with a mean age ...
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...
Para-aortic lymph nodes (often shortened to para-aortic nodes) are part of the retroperitoneal nodes, and are located anterior to the left lumbar trunk 1 and above and below the left renal vein prior to the flow of lymph into the cisterna chyli 2-4.
A paraduodenal or juxtaduodenal hematoma refers to a retropertoneal hematoma arising just adjacent to the duodenum.
It may result in intestinal obstruction from compression
Paraduodenal hernias, although uncommon, have classically been the most common type of internal hernia. However, the incidence of postoperative internal hernias has been increasing recently. The two most common types, the left and right paraduodenal hernia involve small bowel herniating through ...
Paraduodenal pancreatitis is an uncommon type of focal chronic pancreatitis affecting the groove between the head of the pancreas, the duodenum and the common bile duct.
The following entities with which it shares clinicopathological features are unified by this term and should no ...
Paragangliomas, sometimes called glomus tumors, are rare neuroendocrine tumors arising from paraganglia.
Paraganglia are clusters of neuroendocrine cells dispersed throughout the body and closely related to the autonomic nervous system, with either parasympathetic or sympathetic f...
A mnemonic for the common causes of paralytic ileus is:
The classic "5 Ps" are:
P: potassium: low (also disturbances of other electrolytes)
P: pelvic and spinal fractures
However, there are a few further Ps that can be include...