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Pancreatic calcifications

Pancreatic calcifications can arise from many etiologies. Punctate intraductal calcifications chronic pancreatitis alcoholic pancreatitis (20-40%) 2 intraductal, numerous, small, irregular preponderant cause of diffuse pancreatic intraductal calcification gallstone pancreatitis (2%) 2 m...

Pancreatic ductal adenocarcinoma (staging)

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...

Pancreatic ducts

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 Vater through the s...

Pancreatic intraductal tubulopapillary neoplasm

Pancreatic intraductal tubulopapillary neoplasms (ITPNs) are rare variants of intraductal papillary neoplasms. Unlike an IPMN, an ITPN does not produce mucin. Epidemiology Incidence/prevalence is unclear. Small series show an even male:female distribution and an average age of presentation of ...

Pancreatic intraepithelial neoplasia

Pancreatic intraepithelial neoplasia (PanIN) is a precursor lesion to pancreatic ductal adenocarcinoma, but the frequency at which this transition occurs is unknown. Epidemiology Increasing incidence with age 1. Risk factors: obesity pancreatic lipomatosis 3 Pathology Mostly flat lesions ...

Pancreatic lipoma

Pancreatic lipomas are uncommon mesenchymal tumors of the pancreas. Clinical presentation 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

Pancreatic lipomatosis refers to the fatty replacement of 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 whe...

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...

Pancreatic lymphoma

Pancreatic lymphoma is most commonly a B-cell sub-type of non-Hodgkin lymphoma. Epidemiology 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. Clinical presentation Symptoms are often non-spe...

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 ...

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...

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...

Pancreatico-pleural fistula

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 PEComa

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. Clinical presentation More common in adults (in contrast to lymphangiomas in the head and neck, which are more com...

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...

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: hematoma with minor contusion/laceration but without duct injury grade 2: major contusion/laceration but without duct injury grade 3: distal lacer...

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 visualization difficult. Scanning techni...

Pancreatitis

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, aetiological agent or associated pathology. acute pancreatitis interstitial edematous pancreatitis necrotizing panc...

Pancreatoblastoma

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. Epidemiology There is slight male predilection. Usually occurs in the first decade of life with a mean age ...

Pantaloon hernia

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

Para-aortic lymph nodes 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.

Paraduodenal hematoma

A paraduodenal or juxtaduodenal hematoma refers to a retropertoneal hematoma arising just adjacent to the duodenum. Pathology Causes trauma pancreatitis spontaneous Complications It may result in intestinal obstruction from compression See also duodenal hematoma

Paraduodenal hernia

Paraduodenal hernias, although uncommon, have classically been the most common type of internal hernia. However, incidence of postoperative internal hernias have been increasing recently. The two most common types, the left and right paraduodenal hernia involve small bowel herniating through a c...

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 ...

Paraganglioma

Paragangliomas, sometimes called glomus tumors, are rare neuroendocrine tumors arising from paraganglia. Terminology Paraganglia are clusters of neuroendocrine cells dispersed throughout the body and closely related to the autonomic nervous system, with either parasympathetic or sympathetic f...

Paralytic ileus (mnemonic)

A mnemonic for the common causes of paralytic ileus is: 5 Ps Mnemonic The classic "5 Ps" are: P: postoperative P: peritonitis P: potassium: low (also disturbances of other electrolytes) P: pelvic and spinal fractures P: parturition However, there are a few further Ps that can be include...

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...

Para-esophageal hernia

Para-esophageal 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-esophageal reflux disease (mainl...

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...

Parasympathetic pelvic splanchnic nerves

The pelvic splanchnic nerves also known as nervi erigentes are preganglionic (presynaptic) parasympathetic nerve fibers 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...

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...

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...

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...

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 ischemia colorectal carcinoma aor...

Pelvic lipomatosis

Pelvic lipomatosis or pelvic fibrolipomatosis represents excessive deposition of fat in pelvis due to overgrowth of adipose cells leading to compression of pelvic organs. Epidemiology The condition usually presents in patients 20-50 years of age. The condition is predominantly (2/3 of cases) s...

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...

Peptic ulcer disease (summary)

This is a basic article for medical students and other non-radiologists 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 ...

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...

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. Epidemiology...

Periampullary tumors

Periampullary tumors are those that arise within 2 cm of the ampulla of Vater in the duodenum. Tumors that fall under this group include four main types of tumors 1,4 that will be approached in their specific articles: pancreatic head/uncinate process tumors: includes pancreatic ductal adenoca...

Perianal abscess

Perianal abscess refers to a formed infective-inflammatory collection within the perianal region. It forms part of the broader group of anorectal abscesses. They are often associated with perianal fistulae and are components of grades 2 and 4 fistulae of the St James’ University Hospital classif...

Perianal fistula

Perianal fistula (or fistula-in-ano) is the presence of a fistulous tract across/between/adjacent to the anal sphincters and is usually an inflammatory condition 4. Epidemiology Incidence is estimated at ~1:10 000 1, with a recognised male predilection of 2-4:1. Associations spontaneous div...

Pericaecal hernia

Pericaecal hernia is a rare type of internal hernia. Epidemiology It accounts for only 6-13% of internal abdominal hernias. Clinical presentation Clinical symptoms are often characterized by episodes of intense lower abdominal pain, like a colicky right lower quadrant pain very similar to th...

Perigastric appendagitis

Perigastric appendgitis is a rare inflammatory/ischemic process involving the perigastric ligaments (gastrohepatic, gastrospleic and falciform ligaments). Epiploic appendagitis, greater omental infarction, and perigastric appendagitis have similar mechanisms, clinical presentations, and radiolo...

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...

Perineal membrane

The perineal membrane is a thin triangular horizontal layer of dense tough fascia in the perineum the dividing the urogenital triangle into the superficial (inferior) and deep (superior) perineal pouches. It attaches to the inferior margins of the ischiopubic rami, enclosing the anterior portio...

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...

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 ...

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

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 forming the perirenal space. It is a multi-laminated structure which is fused posteromedially with the muscular fasciae of the psoas a...

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, proximal collecting systems, adrenal glands and an adequate amount of fat to allow identification on CT scanning. It also contains the perin...

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...

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...

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...

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...

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...

Peritoneal mesothelioma

Peritoneal mesothelioma is an uncommon primary tumor 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 subtypes (also discussed separately)...

Peritoneal metastases

Peritoneal metastases are a relatively common location for metastases, particularly from tumors of the abdomen and pelvis, that generally imply a poor prognosis, often with a significant impact on palliation 1. Terminology If peritoneal metastases are of an epithelial origin (as most are) and ...

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...

Peritoneal stripe sign (pneumoperitoneum)

The peritoneal stripe sign in abdominal ultrasonography is considered indicative of intraperitoneal free air, present in pneumoperitoneum. Free air in the abdomen will collect in an anti-dependent manner, typically the anterior prehepatic space in the supine patient, settling against the parieta...

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...

Perivascular epithelioid cell tumors (PEComas)

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

Per-oral esophageal myotomy (POEM)

Per-oral esophageal 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 esophagus with CO2 then cr...

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 gas) of the ascending colon and termina...

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). Fluorine-18 (F-18) is an unstable radioisotope and has a half-...

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...

Peutz-Jeghers syndrome

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

Phlegmonous enteritis

Phlegmonous enteritis is a rare, life threatening disorder characterized by bacterial infection of the submucosal and muscularis layers of the gastrointestinal tract. The stomach is the most commonly involved site, with more than 100 cases reported in the literature. The mortality rate due to ph...

Phlegmonous gastritis

Phlegmonous gastritis, also known as phlegmonitis of the stomach, is an uncommon, life-threatening condition which is due to diffuse infection of the submucosa of the stomach. Epidemiology Although the gastric form is the commonest type of phlegmonitis seen in the gastrointestinal tract, it r...

Phrenic ampulla

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

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 anemia weight loss esophageal webs or hypopharyngeal webs The condition is more common in women.

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...

Pneumatosis cystoides intestinalis

Pneumatosis cystoides intestinalis is a radiopathological entity characterized by the presence of multiple gas-filled cysts in the submucosa and/or gastrointestinal subserosa of the small intestine. It is a subtype of pneumatosis with specific features, which can occur anywhere along the gastroi...

Pneumatosis intestinalis (mnemonic)

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

Pneumoperitoneum

Pneumoperitoneum describes gas within the peritoneal cavity, often due to critical illness. There are numerous causes and several mimics. Pathology The most common cause of pneumoperitoneum is from the disruption of the wall of a hollow viscus. In children, the causes are different from the ad...

Pneumoperitoneum (summary)

This is a basic article for medical students and other non-radiologists 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 ma...

Pneumoretroperitoneum

Pneumoretroperitoneum is by definition presence of gas within the retroperitoneal space. Pathology Pneumoretroperitoneum is always abnormal and has a relatively small differential: perforated retroperitoneal hollow viscus duodenum peptic ulcer disease blunt or penetrating abdominal trauma ...

Point-of-care ultrasound (curriculum)

The point-of-care ultrasound (PoCUS) curriculum is one of our curriculum articles and aims to be a collection of articles that represent the core applications of ultrasonography in a point-of-care setting. Point-of-care ultrasound refers to ultrasonography which may be simultaneously performed,...

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 UK mint sweet, the Polo, also refe...

Polyarteritis nodosa

Polyarteritis nodosa (PAN) is a systemic inflammatory necrotizing vasculitis that involves small to medium-sized arteries (larger than arterioles). Epidemiology PAN is more common in males and typically presents around the 5th to 7th decades. 20-30% of patients are hepatitis B antigen positiv...

Polyglandular autoimmune syndromes

Polyglandular autoimmune syndromes (PAS) are a rare set of diseases characterized 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...

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 Gardner syndrome Turcot syndrome Bannayan–Riley–Ruvalc...

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...

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...

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...

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...

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...

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...

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...

Posterior left perihepatic space

The posterior left perihepatic space (also known as the subhepatic space or gastrohepatic recess) is a potential space that lies between the inferior aspect of the left lobe of the liver and the lesser omentum posteriorly. Gross anatomy The posterior left perihepatic space is separated from th...

Posterior left subphrenic space

The posterior left subphrenic space (also known as the perisplenic space) is a potential space surrounding the spleen. Gross anatomy The posterior left subphrenic space is continuous with the anterior left subphrenic space, both are subcompartments of the left supramesocolic space. Boundaries...

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...

Postoperative free intraperitoneal gas

Postoperative free intraperitoneal gas refers to the presence of gas in the peritoneal cavity following a surgical procedure and may result from open or laparoscopic surgical techniques. Terminology Postoperative free intraperitoneal gas is also referred to as postoperative pneumoperitoneum...

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