Articles

Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

931 results found
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Pancreatic lipomatosis

Pancreatic lipomatosis refers to fatty replacement of pancreatic parenchyma. This finding is most often associated with obesity and aging.  It tends to be commonest pathological condition involving the pancreas. The condition may occassionally simulate a mass like lesion particularly when fatty...
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Pancreatic lymphangioma

Pancreatic lymphangiomas are benign lesions that are often found incidentally during cross-sectional imaging for another reason. Clinical presentation More common in adults (in contrast to lymphangiomas in the head and neck, which are more common in children). Account for approximately 1% of a...
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Pancreatic lymphoma

Pancreatic lymphoma is most commonly a B-cell sub-type of non-Hodgkin lymphoma and is classified as either primary or secondary: primary pancreatic lymphoma is a rare extranodal manifestation of any histopathologic subtype of B-cell non-Hodgkin's lymphoma, representing < 2% of extranodal lympho...
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Pancreatic mesenchymal neoplasms

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 ...
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Pancreatic neoplasms

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

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.  Clinical presentation If they do cause symptoms, it will typically be those related to regional mass effe...
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Pancreatic PEComa

Pancreatic perivascular epithelioid cell tumours (or "Pancreatic PEComas") are a subtype of the larger family of PEComas. Pancreatic PEComas are very rare with <20 cases described. Clinical presentation More common in adults (in contrast to lymphangiomas in the head and neck, which are more co...
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Pancreatic pseudocyst

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. Terminology The following are th...
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Pancreatic trauma injury grading

A number of pancreatic injury grading systems have been proposed. Classifications American Association for the Surgery of Trauma (AAST) grade 1: haematoma with minor contusion/laceration but without duct injury grade 2: major contusion/laceration but without duct injury grade 3: distal lace...
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Pancreatic ultrasound

Pancreatic ultrasound can be used to assess for pancreatic malignancy, pancreatitis and its complications, as well as for other pancreatic pathology. Preparation Fast the patient to reduce interference from overlying bowel gas, which may otherwise make visualisation difficult. Scanning techni...
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Pancreatitis

Pancreatitis refers to inflammation involving the pancreas.  It has various forms which can be classified in many many ways according to time of onset, aetiological agent or associated pathology. acute pancreatitis interstitial oedematous pancreatitis necrotising pancreatitis haemorrhagic p...
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Pancreatoblastoma

Pancreatoblastomas are rare paediatric tumours of the pancreas. However, they are the most common pancreatic neoplasm of childhood and are often associated with a raised alpha-fetoprotein. Epidemiology There is slight male predilection. Usually occurs in the first decade of life with a mean ag...
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Pantaloon hernia

A pantaloon hernia (dual hernia or Romberg's 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 ...
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Para-oesophageal hernia

Para-oesophageal hernias (POH), or rolling hernias, are an uncommon type of hiatal hernia representing ~10% of all hiatal hernias. The majority of the hiatal hernias being of the sliding type. Clinical presentation Can vary and can include: asymptomatic gastro-oesophageal reflux disease (mai...
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Paraduodenal hernia

Paraduodenal hernias, although uncommon, are the most common type of internal hernia. The two most common types, the left and right paraduodenal hernia involve small bowel herniating through a congenital opening in the mesenteries. These internal hernias may result in a closed-loop bowel obstruc...
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Paraduodenal pancreatitis

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. Terminology The following entities with which it shares clinicopathological features are unified by this term and should no ...
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Paralytic ileus (mnemonic)

A mnemonic for the common causes of paralytic ileus is: 5 Ps Mnemonic P: postoperative P: peritonitis P: potassium: low (also disturbances of other electrolytes) P: pelvic and spinal fractures P: parturition
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Paraneoplastic syndromes

Paraneoplastic syndromes occur secondary to the indirect effects of a malignancy and occur remotely to the primary malignancy. Symptoms are mediated by cytokines, hormones or immune cross-reactivity. These syndromes can cause a diverse range of symptoms and can affect multiple systems. Epidemio...
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Parastomal hernia

Parastomal hernia is defined as the protrusion of abdominal contents through an abdominal wall defect in the vicinity of the stoma. Classification The hernia may contain a loop of bowel forming the stoma itself, omentum, and/or intestinal loops other than that forming the stoma. Based on the c...
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Parasympathetic pelvic splanchnic nerves

The pelvic splanchnic nerves also known as nervi erigentes are preganglionic (presynaptic) parasympathetic nerve fibres that arise from S2, S3 and S4 nerve roots of the sacral plexus. These nerves form the parasympathetic portion of the autonomic nervous system in the pelvis.   Gross anatomy O...
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Paraumbilical hernia

Paraumbilical hernias are a type of midline ventral abdominal hernia. Pathology Paraumbilica hernias occur near the umbilicus and abdominal contents protrude through a defect in the linea alba and can be quite large. They are usually related to rectus abdominis muscle diastasis.  Differential...
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Paravesical space

The paravesical spaces are paired avascular spaces of the pelvis. The paravesical spaces generally contain fat, but can become filled with ascites, blood, or other substances during pathological processes. Gross anatomy Boundaries superior: lateral umbilical folds inferior: pubocervical fasc...
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Passavant cushion

The Passavant cushion is a small prominence in the posterior pharynx, formed from a focal bulge of the superior pharyngeal constrictor muscles during swallowing. The "cushion" opposes the soft palate during the act of swallowing and is part of the seal between soft palate and pharynx that preve...
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Pathology in general surgery (summary)

Pathology in general surgery is predominantly intra-abdominal and the core set of conditions listed below is a starting point for final-year medical students: bowel perforation acute pancreatitis appendicitis acute cholecystitis diverticulitis intestinal ischaemia colorectal carcinoma ao...
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Peptic ulcer disease

Peptic ulcer disease (PUD) encompasses a number of entities, united by the presence of mucosal ulceration secondary to the effects of gastric acid. Since the recognition of Helicobacter pylori as a common causative agent, and the development of powerful anti-acid medications, peptic ulcer diseas...
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Peptic ulcer disease (summary)

Peptic ulcer disease encompasses a number of entities that are the result of gastric mucosal ulceration secondary to the effects of gastric acid. Since the recognition of Helicobacter pylori as a common causative agent and the development of powerful anti-acid medications, peptic ulcer disease h...
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Per-oral oesophageal myotomy (POEM)

Per-oral oesophageal myotomy (POEM) is a natural orifice endoscopic surgery that has been gaining increasing use as an alternative to traditional oesophageal myotomies (e.g. Heller myotomy and Nissen fundoplication). With this technique, the endoscopist insufflates the oesophagus with CO2 then ...
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Percutaneous endoscopic gastrostomy

Percutaneous endoscopic gastrostomy (PEG) is a procedure where a is a flexible feeding tube (commonly known as a PEG tube) is inserted through the abdominal wall and into the stomach. This may be placed under endoscopic or radiological guidance, in the latter, the procedure may be known as a per...
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Perforated appendix

A perforated appendix is one of the complications of acute appendicitis. If appendicitis is left untreated, ischemic necrosis of a portion of appendiceal wall may occur, leading to perforation. An appendicolith is thought to be associated with a higher probability of perforation 1. Perforation o...
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Periampullary tumours

Periampullary tumours are those that arise within two cm of the ampulla of Vater in the duodenum. Tumours that fall under this group includes four main types of tumours 1,4 pancreatic head / uncinate process tumours: includes pancreatic ductal adenocarcinoma involving head and uncinate process...
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Perianal abscess

Perianal abscess refers to a formed infective-inflammatory collection within the perianal region. It forms part of the broader group of ano-rectal abscesses. They are often associated with perianal fistulae and are components of grades 2 and 4 fistulae under the classification system suggested ...
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Perianal fistula

Perianal fistula is a presence of a fistulous tract across the anal sphincters. It is usually an inflammatory condition that affects the region around the anal canal 4. Epidemiology Incidence is estimated at ~1:10 000 1, with a recognised male predilection of 2-4:1. Pathology The most common...
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Pericaecal hernia

Pericaecal hernia is a rare type of internal hernia. Epidemiology It accounts for only 6-13% of internal abdominal hernias. Pathology Four subtypes (ileocolic, retrocaecal, ileocaecal, and paracaecal) of herniations occur in the pericaecal fossa (located behind the caecum and ascending colon...
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Perineal hernia

Perineal hernias are rare pelvic hernias, occurring through a defect in the pelvic floor musculature. Epidemiology More common in females, with peak age of presentation between 40 and 60 years.  Pathology Perineal hernias are classified as anterior or posterior depending on their relationshi...
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Perineum

The perineum is a diamond shaped region below the pelvic diaphragm and is divided by an imaginary line drawn between the ischial tuberosities into anteriorly the urogenital triangle and posteriorly the anal triangle. Gross anatomy The perineum is bounded by the pubis anteriorly, the ischial tu...
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Peripancreatic pseudoaneurysm

Peripancreatic pseudoaneurysm refers to the formation of a pseudoaneurysm around the pancreatic gland. It is a rare but potentially lethal complication 5. Epidemiology Formation of pseudoaneurysm can occur in as many as 10% of cases of pancreatitis. The time interval is variable, ranging from ...
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Periportal free gas sign

The periportal free gas sign has been described as being strongly suggestive for upper gastrointestinal hollow viscus perforation. See also bowel perforation (summary) pneumoperitoneum
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Perirenal fascia

The perirenal fascia is a dense, elastic connective tissue sheath that envelops each kidney and adrenal gland together with a layer of surrounding perirenal fat. It is a multi-laminated structure which is fused posteromedially with the muscular fasciae of the psoas and quadratus lumborum muscle...
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Perirenal space

The perirenal space is the largest of the three divisions of the retroperitoneum and is the most easily identified. It contains the kidneys, renal vessels and proximal collecting systems, adrenal glands and an adequate amount of fat to allow identification on CT scanning. The space is surrounde...
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Perisplenitis

Perisplenitis is acute inflammation of the splenic capsule and its peritoneal covering. Epidemiology It is seen uncommonly but there is no data on its actual incidence. Clinical Presentation It is seen usually in young and middle-aged patients, with acute left hypochondrial or lower chest pa...
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Peritoneal calcification

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

A peritoneal CSF pseudocyst is a rare complication of ventriculoperitoneal shunt catheter placement. The time from the last shunting procedure to the development of an abdominal pseudocyst ranges from 3 weeks to 5 years.  Pathology The wall is composed of fibrous tissue without an epithelial l...
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Peritoneal hydatidosis

Peritoneal hydatidosis occurs secondary to seeding of echinococcosis to the peritoneum, usually secondary to rupture of hydatid disease of liver. Pathology Seeding involves the entire peritoneum and gives appearance of an multiloculated mass.  Classification Peritoneal hydatidosis can be pri...
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Peritoneal ligaments

The peritoneal ligaments are double layers of peritoneum that pass from one organ to another or from an organ to one of the abdominal walls. Suspensory ligaments of the liver right triangular ligament left triangular ligament falciform ligament Peritoneal ligaments of the stomach lesser om...
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Peritoneal mesothelioma

Peritoneal mesothelioma is an uncommon primary tumour of the peritoneal lining. It shares epidemiological and pathological features with but is less common than its pleural counterpart, which is described in detail in the general article on mesothelioma. Other sub-types (also discussed separatel...
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Peritoneal metastases

Peritoneal metastases, which if of epithelial origin, as most are, and extensive are also known as peritoneal carcinomatosis, are relatively common particularly in tumours of the abdomen and pelvis and generally imply a poor prognosis, often with a significant impact on palliation 1. Less common...
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Peritoneal spaces

Peritoneal spaces are separate compartments within the peritoneal cavity. These spaces are separated or compartmentalized by various peritoneal ligaments and their attachments.  The peritoneal spaces are important in the peritoneal diseases, ascites, intraperitoneal collections or peritoneal me...
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Peritoneum

The peritoneum is a large complex serous membrane which forms a closed sac within the abdominal cavity. In the female, this closed sac is perforated by the lateral ends of the fallopian tubes. It is a potential space between the parietal peritoneum lining the abdominal wall and the visceral peri...
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Perivascular epithelioid cell tumours (PEComas)

Perivascular epithelioid cells tumours (PEComas) are a group of related mesenchymal tumours and tumour-like conditions found in many locations. This group includes: angiomyolipoma (AML) clear cell 'sugar' tumour of the lung lymphangioleiomyomatosis (LAM) clear cell myomelanocytic tumour (CCM...
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Peroral pneumocolon

Peroral pneumocolon is a technique that can be used during a small bowel follow through (SBFT) to better visualize the ascending colon and terminal ileum. Procedure The goal of a peroral pneumocolon is to create a double contrast study (oral contrast and air) of the ascending colon and termina...
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PET-CT indications

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

Petersen hernias are internal hernias which occur in the potential space posterior to a gastrojejunostomy. This hernia is caused by the herniation of intestinal loops through the defect between the small bowel limbs, the transverse mesocolon and the retroperitoneum, after any type of gastrojejun...
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Peutz-Jeghers syndrome

Peutz-Jeghers syndrome is one of the polyposis syndromes. It has an autosomal dominant inheritance and is characterised by: multiple hamartomatous polyps, most commonly involving the small intestine (predominantly the ileum), but also colon and stomach; mouth and oesophagus are spared mucocuta...
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Phrenic ampulla

The phrenic ampulla (also known as the oesophageal vestibule) is the region between the A-ring and B-ring of the distal oesophagus.  The gastro-oesophageal junction is below the ampulla (and gastric folds should not enter the region of the ampulla). Differential diagnosis The ampulla is more ...
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Plummer-Vinson syndrome

Plummer-Vinson syndrome, also known as the Paterson-Brown-Kelly syndrome, predisposes to hypopharyngeal squamous cell carcinoma and consists of four features: dysphagia iron-deficiency anaemia weight loss oesophageal webs or hypopharyngeal webs The condition is more common in women.
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Pneumatosis coli

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

A helpful mnemonic for remembering the causes of pneumatosis intestinalis is: ChIPS Mnemonic C: chronic obstructive pulmonary disease I:  ischaemia P: pneumatosis cystoides intestinalis S: scleroderma/steroids
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Pneumoperitoneum

Pneumoperitoneum describes gas within the peritoneal cavity, and is often the harbinger of a critical illness. There are numerous causes and several mimics (see article: pseudopneumoperitoneum). Pathology The most common cause of pneumoperitoneum is from the disruption of the wall of a hollow ...
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Pneumoperitoneum (summary)

Pneumoperitoneum describes gas within the peritoneal cavity and is often the harbinger of a critical illness, often perforation of a hollow viscus. Pneumoperitoneum is distinct from pneumoretroperitoneum (much rarer) and may be mimicked by other causes (pseudopneumoperitoneum). Reference articl...
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Pneumoretroperitoneum

Pneumoretroperitoneum is by definition presence of gas within the retroperitoneal space. It is always abnormal and has a relatively small differential: perforated retroperitoneal hollow viscus duodenum peptic ulcer disease blunt or penetrating abdominal trauma endoscopy +/- biopsy (rare) 3...
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Polo mint sign (venous thrombosis)

The polo mint sign is a description given to a venous thrombosis on contrast enhanced CT imaging.  When viewed in the axial plane, a thin rim of contrast persists around a central filling defect due to thrombus. This gives an appearance like that of the popular mint sweet, the polo, also referre...
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Polyglandular autoimmune syndromes

Polyglandular autoimmune syndromes (PAS) are a rare set of diseases characterised by the presence of ≥2 autoimmune endocrine disease. Pathology Three types of PAS have been described.  PAS type I a.k.a. APECED (autoimmune polyendocrinopathy, candidiasis and ectodermal dystrophy) or MEDAC (mu...
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Polyposis syndromes

The polyposis syndromes are disorders in which more than 100 gastrointestinal polyps are present throughout the GI tract: hereditary hereditary nonpolyposis colorectal cancer familial adenomatous polyposis syndrome (FAPS) classic FAP attenuated FAP Gardner syndrome  Turcot syndrome Bann...
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Polysplenia syndrome

Polysplenia syndrome, also known as left isomerism, is a type of heterotaxy syndrome where there are multiple spleens congenitally as part of left-sided isomerism. Epidemiology Polysplenia is seen predominantly in female patients. It is usually diagnosed in childhood or adulthood, later than a...
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Portal hypertensive gastropathy / enteropathy / colopathy

In portal hypertension, chronic portal venous congestion leads to dilatation and ectasia of the submucosal vessels in the stomach (portal hypertensive gastropathy), small bowel (portal hypertensive enteropathy) and/or large bowel (portal hypertensive colopathy). This may result in upper or lower...
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Portal vein calcification

Portal vein calcification is a rare radiologic finding which can be seen in long-standing portal venous hypertension. Pathology Calcium may be deposited in a thrombus or in the wall of the portal vein and is more rarely found in the splenic vein and superior mesenteric vein. One of the propos...
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Portal venous gas

Portal venous gas is the accumulation of gas in the portal vein and its branches. It needs to be distinguished from pneumobilia, although this is usually not too problematic, when associated findings are taken into account along with the pattern of gas (i.e. peripheral in portal venous gas, cent...
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Portal venous system

The portal venous system refers to the vessels involved in the drainage of the capillary beds of the GI tract and spleen into the capillary bed of the liver. Blood flow to the liver is unique in that it receives both oxygenated and deoxygenated blood. As a result, the partial pressure of oxygen...
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Portosystemic collateral pathways

Portosystemic collateral pathways (also called varices) develop spontaneously via dilatation of pre-existing anastomoses between the portal and systemic venous systems. This facilitates shunting of blood away from the liver into the systemic venous system in portal hypertension, as a means for r...
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Portosystemic shunt ratio

The portosystemic shunt ratio is a measure performed using ultrasound to quantify the abnormal flow of portal venous blood that is shunted away from the hepatic sinusoidal circulation in the context of a congenital portosystemic shunt 1. Ultrasound The ratio is determined using the following e...
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Post transplant lymphoproliferative / lymphoproliferation disorder (PTLD)

Post transplant lymphoproliferative/lymphoproliferation disorder (PTLD) is increasing in prevalence as the number and survival length of solid organ and bone-marrow transplant recipients also increases. It represents a variety of conditions varying from lymphoid hyperplasia to malignancy but is...
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Posterior pararenal space

The posterior pararenal space is the smallest and most clinically insignificant portion of the retroperitoneum. Gross anatomy It is filled with fat, blood vessels and lymphatics, but contains no major organs. Boundaries posteriorly: bound by transversalis fascia anteriorly: bound by posteri...
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PPP syndrome

PPP syndrome is the extremely rare association of pancreatitis, panniculitis, and polyarthritis. Epidemiology Most commonly affects middle-aged male patients with a history of heavy alcohol use 1,2.  Clinical presentation In the majority of cases, abdominal symptoms are mild or absent, makin...
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Presacral space

The presacral space is located between the rectum and the sacrococcygeal part of the spine. Gross anatomy Contents The presacral space contains a variety of tissue: fat mesenchymal tissue lymph nodes nerve plexuses blood vessels Boundaries superior - peritoneal reflections inferior - ...
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Presbyoesophagus

Presbyoesophagus is term that has been traditionally used to describe the manifestations of degenerating motor function in the aging oesophagus. Presbyoesophagus remains controversial given it was initially described in elderly patients with significant co-morbidities (e.g. dementia, diabetes),...
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Primary cutaneous melanoma

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...
Article

Primary peritoneal neoplasms

Primary peritoneal neoplasms comprise of an uncommon group of heterogenous entities. The list includes mesothelial derivatives primary (malignant) peritoneal mesothelioma primary perioneal multicystic mesothelioma primary peritoneal well differentiated papillary mesothelioma primary perito...
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Primary pneumatosis intestinalis

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

Primary retroperitoneal neoplasms

Primary retroperitoneal neoplasms are an extremely rare group of tumours (lymphoma is not included in this definition). The most common type is soft tissue sarcoma (90%). Epidemiology The most common age for presentation is 40-50 years.  Clinical presentation Frequently tumours have relative...
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Primary serous papillary carcinoma of the peritoneum

A primary serous papillary carcinoma of the peritoneum (PSPCP) is an extremely rare primary peritoneal tumour. Epidemiology They usually present in postmenopausal women. Clinical presentation Patients tend to present with non-specific complaints such as abdominal pain, anorexia, and abdomina...
Article

Properitoneal fat

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. Terminology The properitoneal fat pad is known as a plane in surgical anatomy, a...
Article

Pseudo vein sign (bowel)

The pseudo vein 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 “pseudo-vein” persists b...
Article

Pseudoachalasia

Pseudoachalasia is achalasia-pattern dilatation of the oesophagus due to the narrowing of the distal oesophagus from causes other than primary denervation. One of the most common causes is malignancy (often submucosal gastric cancer) with extension in the lower oesophagus. The clinical and imagi...
Article

Pseudomyxoma peritonei

Pseudomyxoma peritonei refers to the intraperitoneal accumulation of a gelatinous ascites secondary to rupture of a mucinous tumour. The most common cause is a ruptured mucinous tumour of the appendix/appendiceal mucocoele 10.   Occasionally, mucinous tumours of the colon, rectum, stomach, panc...
Article

Pseudopancreatitis

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...
Article

Pseudopneumoperitoneum

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

Pyloric stenosis

Hypertrophic pyloric stenosis (HPS) refers to the idiopathic thickening of gastric py­loric musculature which then results in progressive gastric outlet obstruction. Epidemiology Pyloric stenosis is relatively common and has a male predilection (M:F ~4:1), and is more commonly seen in Caucasia...
Article

Radiation enteritis

Radiation enteritis is a bowel pathology resulting from toxic effects of radiotherapy on the bowel wall and vasculature.  Epidemiology 5-15% of patients treated with radiotherapy (usually > 4500cGy) develop chronic radiation enteropathy. Clinical presentation The clinical presentation is non...
Article

Radiological signs (gastrointestinal tract)

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?
Article

Ranson criteria

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. Criteria On admission age: >55 years white blood count: >16 000/mm blood glucose leve...
Article

Rapunzel syndrome

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. Human hair (especially long hair) is resistant to digestion as well as peristalsis. So it tends to stay in the sto...
Article

RASopathies

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

Rat-tail sign (oesophagus)

The rat-tail sign is used to refer to the tapering of the inferior oesophagus in achalasia. The same appearance (although it is difficult to see the similarity) is also referred to as the ​bird beak sign (oesophagus). 

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