PPP syndrome is the extremely rare association of pancreatitis, panniculitis, and polyarthritis.
Most commonly affects middle-aged male patients with a history of heavy alcohol use 1,2.
In the majority of cases, abdominal symptoms are mild or absent, makin...
Pre-aortic nodes are part of the abdominopelvic lymph nodes. They include 3 main groups:
drainage from gastric nodes, hepatic nodes and pancreaticosplenic nodes
superior mesenteric nodes
drainage from mesenteric nodes
inferior mesenteric nodes
drainage from mesenteric nodes
The presacral space is located between the rectum and the sacrococcygeal part of the spine.
The presacral space contains a variety of tissue:
superior - peritoneal reflections
inferior - ...
Presbyoesophagus is term that has been traditionally used to describe the manifestations of degenerating motor function in the aging esophagus.
Presbyoesophagus remains controversial given it was initially described in elderly patients with significant co-morbidities (e.g. dementia, diabetes), ...
Primary cutaneous melanoma is the most common subtype of malignant melanoma, a malignant neoplasm that arises from melanocytes. Melanocytes predominantly occur in the basal layer of the epidermis but do occur elsewhere in the body. Primary cutaneous melanoma is by far the most common type of pri...
Primary peritoneal neoplasms comprise an uncommon group of heterogenous entities.
The list includes:
primary (malignant) peritoneal mesothelioma
primary peritoneal multicystic mesothelioma
primary peritoneal well-differentiated papillary mesothelioma
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.
Primary pneumatosis i...
Primary retroperitoneal neoplasms are an extremely rare group of tumors (lymphoma is not included in this definition). The most common type is soft tissue sarcoma (90%).
The most common age for presentation is 40-50 years.
Frequently tumors have relatively...
A primary serous papillary carcinoma of the peritoneum (PSPCP) is an extremely rare primary peritoneal tumor.
They usually present in postmenopausal women.
Patients tend to present with non-specific complaints such as abdominal pain, anorexia, and abdominal...
Proctaglia fugax is a disorder characterized by rectal pain that is considered to be functional in etiology, and thus is a diagnosis of exclusion.
The classic presentation, which form the Rome IV diagnostic criteria if all present for three months, include 1,2:
Proctitis refers to inflammation of the lining of the rectum (rectal mucosa) it may be acute or chronic. When is involves the rest of the wider colon, it is then termed proctocolitis.
Proctitis may have a range clinical symptoms which include rectal bleeding, discharge, u...
The properitoneal fat, deep to the transversalis fascia, fills the posterior pararenal space. Laterally it thickens and forms the properitoneal fat pad, which is an anterior extension of posterior pararenal space.
The properitoneal fat pad is known as a plane in surgical anatomy, a...
Pseudoachalasia is achalasia-pattern dilatation of the esophagus due to the narrowing of the distal esophagus from causes other than primary denervation. One of the most common causes is malignancy (often submucosal gastric cancer) with extension in the lower esophagus. The clinical and imaging ...
The pseudokidney of intussusception is an ultrasound finding in some cases of intestinal intussusception. It refers to the longitudinal ultrasound appearance of the intussuscepted segment of bowel which mimics a kidney.
The fat-containing mesentery which is dragged into the intussusception, co...
Pseudomyxoma peritonei refers to the intraperitoneal accumulation of a gelatinous ascites secondary to rupture of a mucinous tumor. The most common cause is a ruptured mucinous tumor of the appendix/appendiceal mucocoele 10.
Occasionally, mucinous tumors of the colon, rectum, stomach, pancrea...
Pseudopancreatitis refers to the presence of fluid in or around the pancreas in the setting of trauma but in the absence of direct signs of traumatic pancreatic injury. Most patients will have a normal serum lipase level, but amylase has a limited sensitivity and specificity for pancreatic traum...
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...
Pseudopneumoretroperitoneum is the radiographic finding of gas within the abdominal region that mimics the appearance of pneumoretroperitoneum (cf. the analogous pseudopneumoperitoneum i.e. abdominal gas that erroneously suggests pneumoperitoneum).
Causes of pseudopneumoretroperitoneum include...
The pseudovein sign can occur with active gastrointestinal bleeding where contrast extravasation during angiography may have a curvilinear appearance as it pools in the gastric rugae or mucosal folds of bowel, mimicking the appearance of a vein. However, contrast in the “pseudovein” persists bey...
The psoas sign is a classic non-specific finding on the abdominal radiograph, potentially representing retroperitoneal pathology.
Normally on an abdominal radiograph, the lateral margins of both the psoas muscles are clearly visible due to adjacent fat. When the lateral edge of one, or both, ps...
Hypertrophic pyloric stenosis (HPS) refers to the idiopathic thickening of gastric pyloric musculature which then results in progressive gastric outlet obstruction.
Pyloric stenosis is relatively common, with an incidence of approximately 2-5 per 1,000 births, and has a male pred...
Radiation colitis refers to injury-inflammation to to the colon caused by radiation therapy. It is usually associated with treatment for prostate cancer or cervical cancer. It can be part of the spectrum of radiation enteritis (which can occur together). Radiation colitis may develops 6 months t...
Radiation enteritis is a bowel pathology resulting from toxic effects of radiotherapy on the bowel wall and vasculature.
5-15% of patients treated with radiotherapy (usually > 4500cGy) develop chronic radiation enteropathy.
The clinical presentation is non...
A radiologically inserted gastrostomy (RIG) is a procedure where a tube is inserted percutaneously in the stomach, principally to provide nutritional support for patients with swallowing disorders 1.
inadequate oral intake due to dysphagia (neurologic disorder, oesophagal obstructi...
Radiological signs are described across the disciplines of imaging, including the gastrointestinal tract. Fruit-inspired, nature-related, and more feature in the list of signs described for a wide array of pathology. How fascinating are the minds of radiologists work in describing pathology?
Ranson's criteria are useful in assessing prognosis in early acute pancreatitis. The more of the criteria are met the higher the mortality. Ranson's criteria are assessed both at admission and at 48 hours.
age: >55 years
white blood count: >16 000/mm
blood glucose leve...
Rapunzel syndrome is the term for a trichobezoar (gastric 'hair ball') which has a tail-like extension into the small bowel through the pylorus causing gastric outlet obstruction.
For discussion of other gastrointestinal foreign bodies, please see: bezoars.
The patient u...
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.
As a group, RASopathies represent one of the most common malformation syndromes, with an in...
The rat-tail sign is used to refer to the tapering of the inferior esophagus in achalasia. The same appearance (although it is difficult to see the similarity) is also referred to as the bird beak sign (esophagus).
Radiological manifestations of recreational drug use are not infrequently seen as the use of recreational drugs is widespread.
Interestingly, recent reports have suggested a decreasing incidence of reported drug use in the general population over the past decade, but it remains th...
Rectal cancer, although sharing many of the features of generic colorectal carcinoma (CRC), has some features that make it unique. These are predominantly related to its anatomical location which has implications in both preoperative imaging assessment and surgical technique.
Demographics and c...
Pelvic MRI protocol for rectal cancer includes:
through tumor (always ensure planes are exactly perpendicular to the wall)
narrow field of view images to be included
Staging strongly influences the success of and rate of local recurrence following rectal cancer resection. MRI is the modality of choice for the staging of rectal cancer, to guide surgical and non-surgical management options. MRI is used at diagnosis, following downstaging chemoradiotherapy, and...
Rectal foreign bodies are not uncommon in emergency departments around the world, and although they are often the source of endless amusement do potentially cause management difficulties.
The incidence varies according to the region, said to be uncommon in Asia and most common in ...
Rectal prolapses refer to the prolapse of the rectum into the anal canal. They can involve the entire wall of the rectum or only the mucosal layer.
Rectal prolapse in Western populations is more common in females (M:F 1:4). In women, it is more common over the age of 50 years. In ...
Rectocele refers to a herniation or bulge of the rectal wall, with the most common type being an anterior rectocele where the bulge is into the posterior vaginal wall in a female patient. Rectocoeles can also occur posteriorly or laterally. Rectocoele is the term most commonly used by colorectal...
The rectosigmoid ratio is a measurement of the diameter of the rectum divided by that of the sigmoid colon during contrast enema. It is of particular use in the diagnosis of Hirschsprung disease.
Normal children have a rectum that is larger than the sigmoid (i.e. rectosigmoid ratio >1). In fact...
Rectovesical pouch is the forward reflection of the peritoneum from the lower third of the rectum to the upper part of the bladder in males.
The rectovesical pouch is the lowest part of the peritoneal cavity and usually contains loops of small bowel or sigmoid colon. It is 7.5 cm...
The rectum is the last part of the large intestine. It is located within the pelvis and is the continuation of the sigmoid colon after the rectosigmoid junction and continues as the anal canal at the anorectal angle created by puborectalis.
At the level of the S3 vertebral body,...
Reflux management systems refer to medical devices that offer an alternative to surgical based treatments for severe and medically refractory gastro-esophageal reflux disease.
Indications for the surgical management of gastro-esophageal reflux disease include gastro-esophageal reflux disease re...
Refractory celiac disease is a rare subtype of celiac disease typified by a lack of resolution of symptoms despite 6-12 months of a strict gluten-free diet, and in the absence of other factors that may affect disease response or the presence of malignancy.
Precise figures for the ...
Renal cysts and diabetes syndrome (RCAD), also known as maturity-onset diabetes of the young, type 5 (MODY5), refers to the combination of renal cortical cysts and diabetes mellitus in patients with mutations in the HNF1B gene. When renal cysts are associated with these mutations without disturb...
A Replogle tube is a medical device used in the treatment of babies with esophageal atresia. The tube is double-lumen and is inserted through the nostril and into the blind-ending esophageal pouch where it is then used to drain the pooled saliva. This prevents the secretions overflowing into the...
Retained barium in appendix refers to the presence of barium in appendix beyond 72 hours from the start of procedure.
Previously used as a sign of appendicitis.
Retained barium outlining the appendiceal lumen allows evaluation of its width and contou...
Retroperitoneal fasciitis is a rare potentially life-threatening infection of the retroperitoneum. It is the retroperitoneal equivalent of necrotizing fasciitis or non-necrotizing soft tissue fasciitis, and just like its soft tissue counterpart, can also be either necrotizing or not.
Retroperitoneal hemangiomas are almost always of the cavernous hemangioma2.
They tend to be asymptomatic, especially in the early stages of their development, but when present, symptoms are non-specific and due to mass effect on adjacent anatomic structure.
Retroperitoneal hydatid infection refers to the presence of hydatid cyst in the retroperitoneal region of the abdomen.
For a general discussion, and for links to other system specific manifestations, please refer to the article on hydatid disease.
It is generally seen secondary to ...
Retroperitoneal liposarcoma is a subtype of liposarcoma, and is a malignant tumor of mesenchymal origin that may arise in any fat-containing region of the body. It is one of the most common primary retroperitoneal neoplasms 2.
There are five histological types:
A useful for mnemonic to remember which organs are retroperitoneal is:
S: suprarenal (adrenal) gland
D: duodenum (second and third part)
P: pancreas (except tail)
C: colon (ascending and descending)
The retroperitoneum is the part of the abdominal cavity that lies between the posterior parietal peritoneum and anterior to the transversalis fascia.
It is divided into three spaces by the perirenal fascia and is best visualized using CT or MRI. The three spaces are:
anterior pararenal space
The reverse figure 3 sign (also known as the E sign) is seen on barium swallows in patients with a coarctation of the aorta and is the medial equivalent of the figure 3 sign seen on plain chest radiographs. It is formed by prestenotic dilatation of the ascending aorta, indentation of the coarcta...
The Revised Atlanta classification of acute pancreatitis is an international multidisciplinary classification of the severity of acute pancreatitis, updating the 1992 Atlanta classification. It was initially revised in 2012 and then further updated in 2016 6.
The worldwide consensus aims for an...
Richter hernias are an abdominal hernia where only a portion of the bowel wall is herniated and comprise 10% of strangulated hernias. These hernias progress more rapidly to gangrene than other strangulated hernias but obstruction is less frequent.
In contrast to most other types of ...
The right colic artery may arise directly from the superior mesenteric artery (SMA) but often arises from a common trunk with the ileocolic artery or middle colic artery.
It courses to the right to the ascending colon and divides into a descending branch that supplies the lower portion of the a...
Right colic flexure (or hepatic flexure) is used to describe the bend in the colon as the ascending colon continues as the transverse colon.
Connective tissue connects this part of the colon to the anterior pararenal fascia, descending part of the duodenum (D2) and head of pancr...
The right gastric artery is a branch of the common hepatic artery which supplies the lesser curvature of the stomach.
The right gastric artery branches off from the common hepatic artery as it turns into the lesser omentum. It runs along the lesser curvature of the stomac...
The right gastroepiploic artery (RGA) arises from the gastroduodenal artery as it divides into its two terminal branches, the right gastroepiploic artery and the superior pancreaticoduodenal artery.
The RGA passes between the first part of the duodenum and the pancreas, ...
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.
The right subhepatic space, or hepatorenal pouch, lies between the upper pole of the right kidney and the inferior surface of the right lobe of the liver.
This is a subcompartment of the right supramesocolic space. The space can be further subdivided in to two other spaces by it...
The right subphrenic space (a.k.a. right anterior space, right subdiaphragmatic space) is a potential space that lies between the right lobe of the liver and the inferior surface of the diaphragm.
This is a subcompartment of the supracolic compartment. It reaches as far as the up...
The right supramesocolic space is an arbitrary subdivision of the supramesocolic space, which lies between the diaphragm and the transverse colon.
The right supramesocolic space is separated from the left supramesocolic space by the falciform ligament, and can be divided into thr...
The Rigler sign, also known as the double wall sign, is seen on a radiograph of the abdomen when the air is present on both sides of the intestine, i.e. when there is air on both the luminal and peritoneal side of the bowel wall.
Pneumoperitoneum may be a result of perforation or, recent instru...
Rigler triad consists of three findings seen in gallstone ileus:
small bowel obstruction
ectopic gallstone, usually in the right iliac fossa
History and etymology
It is named after Leo George Rigler, American radiologist (1896-1979) 1.
Rigler triad should not ...
Ring shadows are radiographic signs seen on either chest x-rays or on upper gastrointestinal fluoroscopy:
ring shadow (chest)
ring shadow (abdomen)
Rokitansky-Aschoff sinuses are diverticula of the gallbladder wall which may be microscopic or macroscopic. Histologically, they are outpouchings of gallbladder mucosa that sit within the gallbladder muscle layer.
They are not of themselves considered abnormal, but may be ass...
The root of the mesentery, or root of the small bowel mesentery to be exact, is the origin of the mesentery of the small intestine (i.e. jejunum and ileum) from the posterior parietal peritoneum., attached to the posterior abdominal wall. It extends from the duodenojejunal flexure to the ileocec...
Rose-thorn ulcers or rose-thorn appearance refers to deep penetrating linear ulcers or fissuring typically seen within stenosed terminal ileum with a thickened wall. They appear as thorn-like extraluminal projections on barium studies and this appearance is one of the typical signs of Crohn dise...
In many centers, 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...
A Roux limb may be formed in multiple different gastrointestinal surgeries, including
bariatric surgery, e.g.
Roux-en-Y gastric bypass
partial pancreaticoduodenectomy (Whipple procedure)
In these surgeries the small bowel is ...
The rugal folds are the mucosal folds within the stomach that give the distinctive appearance on barium studies.
The rule of 2s is a useful mnemonic for Meckel diverticulum.
occur in 2% of the population
are 2 inches (5 cm) long
are 2 feet (60 cm) from the ileocecal valve
2/3rds have ectopic mucosa
2 types of ectopic tissue are commonly present (mostly gastric and pancreatic)
Ruptured omphalocoele occurs when there is rupture of the outer membrane of an omphalocoele. When this happens the eviscerated fetal bowel looks free floating and distinction from gastroschisis becomes difficult. However the abdominal defect generally tends to be larger and may contain liver wit...
The saber sign refers to a pattern of gas distribution seen in supine abdominal radiographs of patients with pneumobilia. A sword-shaped lucency is apparent in the right paraspinal region of the upper abdomen representing arching gas extending from the common bile duct into the left hepatic duc...
Sacral nerve stimulators are a form of neuromodulation therapy. They are used for urogenital disorders such as urge urinary incontinence and detrusor hyperactivity, and colorectal disorders such as chronic constipation refractory to conventional medical therapy, and fecal incontinence. There is ...
A sandwich sign, sometimes known as a hamburger sign, refers to a mesenteric nodal mass, either para-aortic or not, giving an appearance of a hamburger. Confluent lymphadenopathy on both sides of the mesenteric vessels gives rise to an appearance described as the sandwich sign 2.
The sign is sp...
A Schatzki ring, also called Schatzki-Gary ring, is symptomatically narrow esophageal B-ring occurring in the distal esophagus and usually associated with a hiatus hernia.
Relatively common, lower esophageal rings are found in ~10% of oesophagrams.
Scirrhous carcinoma of the gastrointestinal tract is a subtype of primary adenocarcinoma of the gastrointestinal (GI) tract.
It is the least common type of primary adenocarcinoma involving mainly the stomach and the colon.
The tumor demonstrates an infiltrative behavio...
Scleroderma, also known as systemic sclerosis, is an autoimmune connective tissue disorder characterized by multisystem fibrosis and soft tissue calcification. As such, it affects many separate organ systems, which are discussed separately:
musculoskeletal manifestations of scleroderma
Gastrointestinal manifestations of scleroderma can occur in up to 90% of patients with scleroderma 2 with the commonest site of GI involvement being the esophagus.
As the clinical presentation, radiographic appearances and differential diagnosis vary with the location of involvement these are d...
Sclerosing mesenteritis, also referred to as mesenteric panniculitis, is an uncommon idiopathic disorder characterized by chronic non-specific inflammation involving the adipose tissue of the bowel mesentery.
Typically this condition afflicts adults in their sixties with mild ma...
The seatbelt sign is both a clinical and radiological sign. It is simply the presence of bruising/abrasions in the distribution of a seatbelt (i.e. horizontal and/or diagonal) across the abdomen, chest and sometimes neck.
A positive seatbelt sign, in combination with abdominal pain or tenderne...
The seatbelt syndrome is the constellation of traumatic injuries associated with three-point seatbelts:
lumbar spine fracture
Segmental arterial mediolysis (SAM) is an increasingly recognised vascular disease of the middle-aged and elderly and a leading cause of spontanoeus intra-abdominal hemorrhage. It is characterized by fusiform aneurysms, stenoses, dissections and occlusions within splanchnic arterial branches. Im...
Segmental pancreatitis is not a distinct entity in itself but describes an imaging differential.
With segmental pancreatitis, a patient presents with clinical pancreatitis (signs, symptoms, laboratory markers), but on imaging, only a portion of the gland appears to have c...
SeHCAT™ (23-seleno-25-homo-tauro-cholic acid or tauroselcholic acid) is a radiopharmaceutical used in the investigation of bile salt malabsorption, which is a cause of chronic diarrhea.
physical half-life: 118 days
Uses, dosage and timings
A capsule containing SeHCAT is inge...
The semilunar line, linea semilunaris or Spigelian line is a bilateral vertical curved line in the anterior abdominal wall where the layers of the rectus sheath fuse lateral to the rectus abdominis muscle and medial to the oblique muscles.
It is the site of a Spigelian hernia.
A sentinel loop is a short segment of adynamic ileus close to an intra-abdominal inflammatory process.
The sentinel loop sign may aid in localising the source of inflammation. For example, a sentinel loop in the upper abdomen may indicate pancreatitis, while one in the right lower quadrant may ...
Serous cystadenoma of the pancreas, also referred as microcystic adenoma, is an uncommon type of benign cystic pancreatic neoplasm.
There is a recognised strong female predilection (M:F ~ 1:4) and usually presents in middle age to elderly patients (>60 years of age).
Serrated polyposis syndrome (SPS), also called hyperplastic polyposis syndrome, is one of numerous polyposis syndromes and is characterized by the presence of multiple serrated polyps or a mixture of serrated and hyperplastic polyps, with the exact number required for diagnosis dependent on loca...
Seurat spleen is an angiographic appearance seen following blunt trauma to the spleen. Multiple small punctate regions of intraparenchymal contrast extravasation lead to a spotted appearance.
History and etymology
The term refers to a likeness between the angiographic appearance and the artwor...
Shading sign is an MRI finding typically seen in an endometrioma. It may also be seen with some endometrioid tumors (e.g endometrioid carcinoma of the ovary)
It helps to distinguish endometriomas from other blood-containing lesions (e.g. hemorrhagic corpus luteum cysts), with a sensitivity of 9...
Shock bowel is the appearance of the bowel in a state of hypotension. It is usually seen as part of the CT hypoperfusion complex.
thickened bowel loops (>3 mm) with enhancing walls (the reason the condition was previously known as "shock bowel")
on non-contrasted im...
The short gastric arteries are a group of short arteries arising from the terminal splenic artery and the left gastroepiploic artery which supply the fundus of the stomach along it's greater curvature.
The vessels are short in length, variable in number and course through the gastrosplenic liga...