The double beak sign refers to the sudden tapering that two adjacent intestinal loops show in the internal hernia at the transition point of the closed loop obstruction.The marked reduction in caliber results in distension of the afferent and efferent intestinal loops.
History and etymology
The characteristic shape of the crescent has been given to many radiological signs over the years.
crescent sign (disambiguation)
crescent sign (arterial dissection)
crescent sign (inguinal hernia)
crescent sign (intravenous pyelogram)
crescent sign (lung hydatid)
crescent sign (osteonecro...
This is a basic article for medical students and other non-radiologists
Intussusception occurs when a loop of bowel is pulled into the lumen of a distal bowel loop, and is an important cause of acute abdominal pain, particularly in young children.
This is a summary article; ...
A corkscrew esophagus, also known as a rosary bead esophagus, is a classic appearance of distal esophageal spasm on a barium swallow. It is actually quite a rare appearance which is seen in <5% cases of distal esophageal spasm. The finding is caused by multiple tertiary (non-propulsive) contract...
The superficial epigastric vein (TA: vena epigastrica superficialis) is an important tributary of the great saphenous vein that drains the anterior abdominal wall inferior to the level of the umbilicus.
The superficial epigastric vein drains into the great saphenous vein at the saphenous openin...
Diverticula of the anal canal are very rare with only a few cases reported in the global literature.
Patients have presented with anorectal bleeding and/or pain.
The few cases have either not been characterized on imaging or only imaged on barium s...
Intramural pseudocysts are a rare form of pancreatic pseudocysts that occur within the wall of the upper gastrointestinal tract. They may result in gastric outlet obstruction.
They can considerably vary in size with one study reporting a range of 8 mm to 8 cm 1.
The bowler hat sign refers to an appearance on a GI contrast study, which may be seen with both polyps and diverticula of the bowel. The filling defect produced by the pathology mimics the outline of a bowler hat. It was originally described for colonic lesions, but can be seen with lesions thro...
Cameron lesions refer to linear ulcers or erosions that occur on the mucosal folds at the diaphragmatic impression of a hiatus hernia. They are usually radiographically occult and diagnosed endoscopically (although still useful for a radiologist to know).
Their prevalence has been...
The Clermont or DWI-MaRIA scoring system is used to assess ileocolonic Crohn disease activity on noncontrast MRI enterography. It is based on the earlier Magnetic Resonance Index of Activity (MaRIA) index, however, it does not require intravenous gadolinium by substituting relative contrast enha...
Cholecystocolonic fistulas are most commonly a rare late complication of gallstone disease, resulting from an abnormal communication between the gallbladder and the colon. It is the second most common cholecystoenteric fistula after cholecystoduodenal fistulas 1.
The Magnetic Resonance Index of Activity (MaRIA) scoring system is used to assess ileocolonic Crohn disease activity on contrast-enhanced MRI enterography. The segmental index represents disease severity in one bowel segment, whilst assessing six defined anatomic regions these can be combined in...
Rectal MRI is a key imaging investigation in the diagnosis, staging and follow up of rectal cancer. An increase in the utility of rectal MRI as been driven by the recognition of the mesorectum as a distinct anatomic compartment containing and limiting the margins of the rectum, and forming a sur...
Dolichocolon refers to an abnormally elongated redundant colon. It is considered a developmental variant.
The main symptoms and signs of dolichocolon are:
However, dolichocolon is a contentious entity, and so...
The interstitial cells of Cajal are mesenchymal cells closely apposed to neural and smooth muscle cells of the gut. They form a heterogeneous group with differing ultrastructure and functions. One cell type has an ancillary neural function as a gastrointestinal pacemaker, generating electrical s...
Odynophagia is the term given for painful swallowing.
It can arise from a number of causes which include
esophageal inflammation - esophagitis
dysphagia: difficultly swallowing.
An incompetent ileocecal valve is a situation where there can be reflux of backward flow on food content from from the large bowel (cecum) through to the small bowel (terminal ileum) through the ileocecal valve. A low degree of incompetence is not an uncommon finding 3. In some states patients m...
A sphincter (TA: musculus sphincter) is a term used in anatomy to refer a ring of muscle which narrows a tube or closes off a bodily orifice 1.
external anal sphincter
internal anal sphincter
lower esophageal sphincter
The Ram's horn sign is the appearance of a Crohn disease affected stomach seen on a barium meal. If the stomach is involved in Crohn disease it becomes tubular, conical shaped and less distensible giving a curved conical appearance resembling the horn of a ram.
The aerodigestive tract is a non-TA descriptive collective term for the respiratory tract and proximal portion of the digestive tract. As it is a non-standard term, its precise components vary somewhat with the context in which the term is being employed.
Definitions of what precis...
The Van Assche index is a semiquantitative scoring system originally developed in 2003 to assess the severity and disease response in perianal fistulizing Crohn disease. In 2017 substantial changes were proposed to the original system, resulting in the modified Van Assche index. Both system rema...
A mnemonic to remember the contraindications to abdominal paracentesis is:
C: coagulopathy (INR >2.0)
A: abdominal wall cellulitis
S: surgical abdomen (absolute contraindication) / severe thrombocytopenia (platelet count <50 x 103/μL)
I: intra-abdominal adhes...
The Pediatric Appendicitis Score (PAS) is a clinical decision rule and predictor of the likelihood of acute appendicitis in the pediatric population.
cough/percussion/hopping tenderness in right lower quadrant (+2)
nausea or emesis (+1)
tenderness in righ...
A mnemonic to remember the severity criteria for acute pancreatitis is:
P: PAO2 <8 kpA
A: age >55 years
N: neutrophilia (WBC >15 x 109 / L)
C: calcium <2 mmol/L
R: renal (urea >16 mmol/L)
E: enzymes (LDH >600 IU/L and AST >200 IU/L)
A: albumin (serum) <32 g/L
Small intestine diverticular disease is an uncommon form of diverticular disease and can be classified into disease affecting the:
non Meckel diverticular disease
duodenum - duodenal diverticulosis
jejunum and ileum - jejuno...
The portal venous phase, also known as the late portal phase or hepatic phase, is a contrast-enhanced CT or MRI series that has the following characteristics:
liver parenchyma is at its peak enhancement with a density >110 HU (an increase of at least 50 HU from the unenhanced baseline)1,2
Rosenbach sign or phenomenon is a clinical sign described in hemiplegia.
The sign refers to the absence of an abdominal wall skin reflex when stroking the paralyzed side of a patient; conversely on the unaffected side, the reflex is normal 1.
Rosenbach gave his name to two other cli...
Obturator sign is a clinical sign of acute appendicitis, it is defined as discomfort felt by the subject/patient on the slow internal movement of the hip joint, while the right knee is flexed. It indicates an inflamed pelvic appendix that is in contact with the obturator internus muscle 1-3.
The late arterial phase, also known as the corticomedullary phase or early venous portal phase, is a contrast-enhanced CT or MRI series, in which there is an optimal enhancement of structures that get their blood supply directly from the arterial system.
The standard characteristics for this ph...
The steelpan sign refers to the close resemblance of sigmoid volvulus on CT to the percussion instrument known as the steelpan. The steelpan, also known as steel drum or pan, is a Caribbean musical instrument invented in Trinidad and Tobago by the mid-1930s, which became very popular in Trinidad...
Hypervascular splenic lesions are findings that enhance more or similarly to the background splenic parenchyma on late arterial phase, on contrast-enhanced CT or MRI.
splenic hemangioma 2
most common primary benign neoplasm of the spleen
second most com...
The split-wall sign is one of the signs of sigmoid volvulus. This sign is characterized by the separation of the walls of a single loop of the sigmoid colon due to the invagination of mesenteric fat between them. The intervening fat causes the loop to appear bilobed or C-shaped on axial images, ...
Boas sign is a clinical sign that is defined as hyperesthesia felt by the patient to light touch in the right lower scapular region or the right upper quadrant of the abdomen. It is classically seen in patients with acute cholecystitis.
History and etymology
Ismar Isidor Boas (1858–1938), was ...
The Carnett sign describes an examination finding used to distinguish pain arising from the abdominal wall from pain arising from within the abdomen itself.
Eliciting the sign was described as a two-stage procedure. First the examiner locates the point of maximal tenderness through palpation of...
Blumberg sign is defined as discomfort on the manual application of tension over the abdomen observed by simultaneously watching the subjects face. On the removal of the examiner's hand the patient should be again asked whether he or she is feeling pain or not. It is expressive of peritoneal irr...
Rovsing sign is commonly used to describe pain elicited in the right iliac fossa on deep palpation of the left iliac fossa.
It is used in clinical examination to detect peritoneal irritation in the right iliac fossa, most frequently associated with acute appendicitis. Most teaching erroneously...
Aaron sign is a clinical sign that is defined as a feeling of distress and pain in the epigastric, umbilical and praecordial regions, on steady pressure over McBurney point, it is suggestive of chronic appendicitis.
History and etymology
Charles Dettie Aaron (1866–1951) was an American gastroe...
Cullen sign refers to superficial edema visible as periumbilical discolouration and is most commonly seen in patients with acute pancreatitis 1-3.
Clinically patients with pancreatitis present with epigastric pain that radiates to the umbilical/periumbilical region and th...
Gastrointestinal (GI) bleeding may be either:
upper GI bleeding
bleeding proximal to the ligament of Treitz, i.e. proximal to the duodenojejunal (DJ) junction
lower GI bleeding
bleeding distal to the ligament of Treitz, i.e. distal to the DJ junction
This bleeding may present as
Splenic vein thrombosis (plural: thromboses) is an uncommon condition in which the splenic vein becomes thrombosed, that most frequently occurs in the context of pancreatitis or pancreatic cancer. Whilst, for the most part asymptomatic, splenic vein thrombosis increases risk of gastric varices a...
Persistent descending mesocolon is defined as the failure of fusion of the mesentery of the descending colon with the lateral and posterior parietal peritoneum 1.
Persistent descending mesocolon is a rare congenital anomaly, in which the primitive dorsal mesocolon does not fuse w...
The Pediatric Appendicitis Risk Calculator (pARC) is a clinical decision rule and predictor of the likelihood of acute appendicitis in pediatric patients. Due to the non-categorical data of some variables within the criteria, an integrated calculator is required to use this tool.
The Z-track technique is used for paracentesis. It produces a non-linear track between the dermis and the peritoneum, and this serves to decrease the chance of ascitic fluid leakage through the track.
Instead of directly sticking the access needle from the skin surface into the perit...
Gastropericardial fistulas are rare abnormal communications between the stomach and the pericardial sac. This is a life-threatening condition that can lead to impaired cardiac function, sepsis and eventually death.
Patients with gastropericardial fistula may present with ...
Anterior resection is a surgical procedure to resect the rectum and sigmoid colon while preserving the anal sphincter complex.
cancer of the rectum (most commonly)
severe diverticular disease
Although historically an open procedure, most anterior resections are now per...
The CT chest-abdomen-pelvis protocol serves as an outline for an examination of the trunk covering the chest, abdomen and pelvis. It is one of the most common CT examinations conducted in routine and emergencies. It can be combined with a CT angiogram.
Note: This article aims to frame a genera...
The CT abdomen-pelvis protocol serves as an outline for an examination of the whole abdomen including the pelvis. It is one of the most common CT protocols for any clinical questions related to the abdomen and/or in routine and emergencies. It forms also an integral part of trauma and oncologic ...
The CT pancreas protocol serves as an outline for a dedicated examination of the pancreas. As a separate examination, it is usually conducted as a biphasic contrast study and might be conducted as a part of other scans such as CT abdomen-pelvis, CT chest-abdomen-pelvis.
Note: This article aims...
Rectal diverticulosis (plural: diverticuloses) or the presence of diverticula in the rectum is very rare.
Rectal diverticula are very rare with only scattered case reports in the global medical corpus, and symptomatic cases, e.g. rectal diverticulitis, are even rarer 1. It has bee...
The APPEND score is a clinical decision rule and predictor of the likelihood of acute appendicitis.
male gender (1)
migratory pain (1)
localized peritonism (1)
elevated CRP > 15mg/L (1)
neutrophilia >7.5x109/L (1)
APPEND refers to the mnemonic:
A diaphragmatic lung hernia (plural: hernias or herniae) is extremely rare, characterized by a lung herniation through the diaphragm into the abdominal cavity. There has been a single case report 2.
This is not to be confused with the far more common congenital or traumatic diaphragmatic herni...
Anusitis is inflammation of the anal canal lining.
Anusitis should not be confused with proctitis, which is distinguished as inflammation of rectal mucosa.
Anusitis is associated with diet, in particular excess intake of coffee, cola, beer, citrus, spices, and/or hot...
The marginal artery may refer to several different arteries in the body, including two different coronary vessels:
callosomarginal artery (CNS)
marginal artery (of Drummond)
obtuse marginal artery (cardiac)
right marginal artery (cardiac)
The viscera (singular: viscus) refers to all the internal organs within the major cavities of the thorax, abdomen and pelvis. Therefore it does not include organs of the CNS, head and neck or musculoskeletal compartments nor does it encompass non-internal organs (e.g. the skin) 1.
A right hemicolectomy is a surgical procedure to remove the cecum and ascending colon.
cancer of the appendix, cecum or ascending colon (most common) 1
inflammatory bowel disease, particularly Crohn disease
perforation of the right colon
The O sign is a radiographic sign described in gastric band slippage. Normally, a correctly-sited laparoscopic gastric band lies such that its anterior and posterior margins are superimposed in the anteroposterior orientation and a oblong morphology is visible on a frontal radiograph.
When a g...
Acute non-traumatic abdominal pain in pregnancy requires a considered imaging approach due to the increased risks of fetal demise associated with undiagnosed diseases such as perforated acute appendicitis. Ultrasound is the first-line modality due to its wide availability and ability to diagnose...
The abdominal pain in pregnancy MRI protocol encompasses a set of MRI sequences for assessment of causes of non-traumatic abdominal pain in pregnancy.
Note: This article aims to frame a general concept of an MRI protocol for the assessment of the abdomen in pregnancy. Protocol specifics will va...
Pancreatic acinar cell carcinoma is a rare exocrine neoplasm that comprises ~1% of all pancreatic tumors. This tumor shows more aggressive behavior than the far more common adenocarcinoma 1,3,4.
High levels of serum lipase, due to hypersecretion syndrome, resulting in sub...
Post-polypectomy coagulation syndrome occurs during a colonoscopic polypectomy procedure when electrocoagulation injury causes a transmural burn to the colon without radiographic evidence of perforation 1,2.
Post-polypectomy coagulation syndrome is also known as post-polypectomy ...
Ingested foreign bodies in adults, in contrast to in children, is often accidental. It usually occurs accidentally in association with food consumption and is most common in adults with underlying gastrointestinal tract pathology. Cases of intentional foreign body ingestion in adults are seen mo...
Lipomas of the ileocecal valve are a rarer entity than the more commonly occurring lipomatosis of the ileocecal valve. They can be differentiated from the latter as they have a demarcating capsule around the fatty tissue and are confined to only one of the ileocecal valve lips 1. Pathologically ...
Mnemonics to remember the classic triad of multiple endocrine neoplasia type 1 (MEN1) are:
P: pituitary adenoma: prolactinoma is commonest
P: pancreatic endocrine tumors
P: parathyroid proliferative disease
parathyroid hyperplasia (most common)
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.
Signs inspired by the letter V have been described in several different pathologies:
inverted V sign (pneumoperitoneum)
inverted V sign (spinal cord)
Naclerio V sign (pneumomediastinum)
Hematemesis is the vomiting of blood, it is an indication of upper gastrointestinal bleeding. Mortality is generally near to 10% 1,2,4. Please see the main article on upper gastrointestinal bleeding for more detail.
Treatment and prognosis
In patients with moderate to severe hematemesis, life...
An intrapancreatic accessory spleen is a splenunculus within the pancreatic parenchyma.
Differentiating this finding from other pancreatic neoplasms is important to avoid unnecessary surgery.
Intrapancreatic splenunculi are not as rare as previously thought and their incidence ra...
Acute mesenteric ischemia accounts for the majority (around 95%) of cases with mesenteric ischemia and comprises of:
arterial occlusive mesenteric ischemia (60-85%)
embolic acute mesenteric ischemia (EAMI)
thrombotic acute mesenteric ischemia (TAMI)
non-occlusive mesenteric ischemia (NOMI) (...
Hypervascular pancreatic lesions are findings that enhance more or similarly to the background pancreatic parenchyma in the late arterial phase, on contrast-enhanced CT or MRI.
intrapancreatic accessory spleen: should not be overdiagnosed as a malignant tumor
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...
The presence of gas in the pancreatic gland and/or the pancreatic ducts is an uncommon finding.
Causes of gas in the pancreatic ducts
altered function and/or anatomy of the sphincter of Oddi: causes duodenal-pancreatic duct reflux
patulous pancreatic duct opening 2
Small bowel (SB) perforation is an acute pathological condition resulting from a discontinuity of the small bowel wall secondary to different etiologies with subsequent leakage of intestinal gas and contents into the peritoneal cavity.
clinical diagnosis maybe difficult, ...
A useful mnemonic to remember which organs are intraperitoneal is:
SALTD SPRSS (pronounced 'salted spurs')
T: transverse colon
D: duodenum (first part)
S: small intestines (jejunum and ileum)
P: pancreas (only tail)
R: rectum (upper third)
Bucket handle mesenteric injuries are avulsions of the mesentery off a bowel segment (the handle) due to shearing forces in blunt trauma to the bowel and mesentery. Laceration of the mesenteric vessels results in intestinal ischemia.
The most common mechanism of injury in...
Falciform ligament hernias (alternative plural: herniae) are a very rare type of internal hernia occurring through a defect in the falciform ligament.
Exceedingly rare, thought to comprise just 0.2% of all internal hernias 4.
laparoscopic surgery 2
Ascitic fluid cholesterol level estimation is a simple and precise test for differentiating malignant ascites from non-malignant (cirrhotic) ascites 5-9.
Ascites is the abnormal collection of fluid within the peritoneal cavity. Malignant ascites comprises ~10% and is usually seconda...
The Chinese dragon sign is a radiological sign on abdominal radiograph and CT describing the radiologic appearance of calcified tortuous splenic artery that resembles a Chinese dragon. The tortuous splenic artery segment on the splenic hilum side represents the dragon head while the other arteri...
Splenic volvulus (rare plural: volvuli) also called splenic torsion may be seen as a complication of a wandering spleen due to weakness of the splenic ligaments 1.
abdominal pain: mild to severe in intensity which depends on the degree of torsion 4-6
abdominal mass 5
Chronic appendicitis (rare plural: appendicitides) is defined by inflammation of the appendix over time with symptoms lasting for more than three weeks duration (cf. acute appendicitis) 1. The condition should be differentiated from recurrent appendicitis, in which one or more episodes of flares...
Splenic sarcoidosis is a non-caseating granulomatous involvement of the spleen, that presents with splenomegaly or multiple splenic nodules.
Clinical features of splenic sarcoidosis include 5,6:
abdominal pain and discomfort
splenic enlargement (is associa...
The perineal body, also known as the central tendon of the perineum, (TA: corpus perineale) is a key midline fibromuscular structure, with important muscular attachments, which acts to stabilize the structures of the pelvis and perineum. It is located between the anal canal and the bulb of the p...
Internal supravesical hernias (alternative plural: herniae) are a type of internal hernia in which viscera protrude into the supravesical fossa, occupying the paravesical space.
It is a very rare condition and accounts for less than 4% of all internal herniae 4.
Supravesical hernias (alternative plural: herniae) are a type of abdominal hernia in which viscera protrude through the supravesical fossa.
Laxity with failure of the transversalis fascia and the transversus abdominis muscle are the main cause of supravesical hernias in virgin abdome...
Mesorectal lymph nodes refers to lymph nodes that are present in the mesorectal fascia. Their assessment is important in the staging of colorectal tumors such as rectal cancer and anal cancer.
According to one study, the majority of nodes were located in the proximal two-thirds ...
Broad ligament hernias (alternative plural: herniae) are a type of internal hernia in which small bowel passes through a congenital or acquired defect in the broad ligament.
Broad ligament herniation is very rare and accounts for 4%-7% of all internal hernias 1.
An ileostomy is a surgical method in which a loop of the distal small bowel is connected and opened through the outer abdominal wall to artificially create a connection and bypass the large bowel.
There are two types of ileostomies:
permanent end ileostomy
A permanent end il...
Peritoneal to abdominal height ratio (PAR) ≥ 0.52 is a statistically associated sign for raised intra-abdominal pressure > 12 mmHg in the context of abdominal compartment syndrome in critically ill patients in CT.
It can be calculated by dividing the distance from the linea alba to the poster...
Intrathoracic sleeve migration is a rare complication following a sleeve gastrectomy.
Several factors have been postulated, including 3
progressive enlargement of the esophageal hiatal orifice
division of natural attachments such as the phreno-esophageal membran...
The terminology used in describing the stage and features of rectal cancer staging is based on using abbreviations and prefixes to denote the specific stage identifier, modality of assessment and the patient's position in the treatment journey 1.
Abbreviations and letters used in s...
Rectus sheath hernias (alternative plural: herniae) are a very seldom seen form of herniation through the anterior abdominal wall. Herniation of intra-abdominal contents (mesenteric fat +/- bowel), is usually through the posterior rectus sheath only and thus these are often termed posterior rect...
Fecal impaction is the inability to spontaneously evacuate solid feces. It is common in the elderly population. A severe form of fecal impaction is often referred to as a fecaloma.
Fecal loading is a poorly defined term but generally refers to the volume of fecal material in the c...
Assessment of rectal cancer response to therapy, which may be chemotherapy, radiotherapy, or a combination, relies on the synthesis of clinical, endoscopic and radiologic evaluation.
The purpose of neoadjuvant therapy is to downstage the tumor, to facilitate surgical resection and reduce local...
Differential diagnoses of cirrhotic liver nodules include regenerative liver nodules, dysplastic liver nodules, and hepatocellular carcinoma (HCC), all represent a spectrum of diseases ranging from non-neoplastic reparative process (regenerative) to nuclear atypia (dysplastic) to typical neoplas...