A pseudocyst is an abnormal fluid filled cavity which is not lined by epithelium. It is this fact that distinguishes if pathologically from a cyst, which is lined by epithelium.
Examples of pseudocysts are:
pseudocysts of the germinal matrix
Pseudolipoma of the Glisson capsule is an uncommon developmental anomaly in which a piece of colonic epiploic fat becomes ectopically located within the liver capsule.
well-circumscribed fat attenuation (-20 to -70 HU) nodule at the liver surface
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...
The Puestow procedure is a lateral side-to-side pancreaticojejunostomy that is used for the treatment of chronic pancreatitis. The pancreas is essentially filleted along its long axis from the uncinate process to the tail and connected to a Roux en-Y loop of jejunum.
The pancreaticojejunal anas...
There are several pulmonary complications that can arise in the setting of cirrhosis:
hepatopulmonary syndrome (HPS): considered the commonest
portopulmonary hypertension (POPH)
hepatic hydrothorax (HH)
Dyspnoea and arterial hypoxemia are the most common symptoms.
Pylephlebitis, also known as ascending septic thrombophlebitis, is a thrombotic occlusion of the portal vein or its branches secondary to infection in regions that drain to this venous system.
septic focus: diverticulitis, appendicitis
Regenerative liver nodules (RNs) are a form of non-neoplastic nodules that arise in a cirrhotic liver.
This may be slightly different from the term nodular regenerative hyperplasia, which are described histopathologically as regenerative nodules with little or no hepatic fibrosis a...
Retained gallstones are common during laparoscopic cholecystectomy, with a reported incidence of 0.1–20%, and occur when gallstones are inadvertently spilled into the peritoneal cavity.
When recognised intraoperatively spilled stones should be retrieved to avoid potential complications includin...
The reticuloendothelial system (RES) comprises of a number of tissues:
liver Kupffer cells
A reverse target sign is a potential ultrasound marker for cirrhotic nodules on ultrasound.It represents central iso-hyperechogenecity with surrounding hyperechoic rim .This sign is useful to differentiate metastases from cirrhotic nodules where target sign is seen in liver metastases.
The Revised Atlanta classification of acute pancreatitis (2012) is an international multidisciplinary classification of acute pancreatitis severity. It is an update of the 1991 Atlanta classification of acute pancreatitis.
The worldwide consensus aims for an internationally agreed-upon classifi...
Rhabdomyosarcomas of the biliary tract are rare tumours, usually identified in children, with a very poor prognosis. They are usually grouped under botryoid rhabdomyosarcomas.
For a general discussion of this type of tumour, please refer to the article on rhabdomyosarcomas.
Riedel lobe is a common anatomical variant of the liver to be aware of because it can simulate a mass.
Its misidentification as a pathologic abdominal mass has led to surgery. Pathology can also occur within it (e.g. malignancy or even torsion) and cause atypical hepatic symptoms low in the pel...
The right hepatic artery (RHA) is formed when the proper hepatic artery (PHA) bifurcates. The hepatic arteries provide 25% of the blood supply and 50% of the oxygen supply to the liver.
The PHA bifurcates into the right and left hepatic arteries on reaching the porta hepatis. The...
The right posterior hepatic notch sign is a sharp indentation of the normally smooth posterior right hepatic lobe margin. It is associated with cirrhosis, although the mechanism is not entirely clear. It has been suggested that this may be an indication of relative caudate lobe hypertrophy and d...
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 triangular ligament is a peritoneal suspensory ligament of the liver. It is formed by the fusion of the superior and inferior reflections of the right coronary ligament.
It is longer than the left triangular ligament and compartmentalises the right subphrenic and subhepatic spaces.
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 rolling stone sign refers to the presence of gallstones within the gallbladder that are mobile when the patient moves.
Small gallstones can sometimes be difficult to diagnose due to the absence of posterior shadow artefact but the presence of a rolling stone sign increases the confidence of...
The rosary sign is a CT finding in adenomyomatosis of the gallbladder. It is formed by the enhanced proliferative mucosal epithelium, with the intramural diverticula surrounded by the unenhanced hypertrophied muscle coat of the gallbladder. The rosary sign is similar to the pearl necklace sign.
The saber sign refers to a pattern of gas distribution seen in supine 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 duct. This i...
A santorinicoele refers to a cystic dilatation of the end of the dorsal pancreatic duct (duct of Santorini) 1,2 and is believed to be analogous to a dilatation of the most distal common bile duct, which is commonly known as a choledochocoele3.
It can occur in association with pancreas divisum...
Sarcoidosis is a systemic inflammatory disease of unknown origin characterized by the formation of non-caseating granulomas. Virtually any organ system may be involved. Although the involvement of abdominal viscera is less frequent than pulmonary and mediastinal disease when it occurs, it may m...
Schistosomiasis (also referred to as bilharzia or snail fever) is the result of infection by blood fluke (trematode worm) of the Schistosoma species.
Schistosomiasis is very common, affecting over 200 million people, with the vast majority (85%) in Africa. It is prevalent in tropi...
Schistosomiasis hepatic manifestations are a chronic result of the deposition of eggs into small portal venules leading to periportal fibrosis and liver cirrhosis.
For a general view over this trematode infection, please refer to the main article on schistosomiasis.
Hepatobiliary manifestations of scleroderma are only present symptomatically in a minority of patients. Around 2.5% of patients with scleroderma develop clinically significant primary biliary cirrhosis, however, antibody studies suggest that subclinical disease may be present in as many as 15% o...
Secondary hepatic involvement with lymphoma (secondary hepatic lymphoma) is common, much more so than primary hepatic lymphoma.
Hepatomegaly with deranged liver function tests is the most common presentation. Jaundice is common. Rarely, patients may present with acute li...
Selective internal radiation therapy (SIRT), also know as hepatic radioembolisation, is a relatively new and developing modality for treating non-resectable liver tumours. The procedure consists of a transcatheter injection of radioactive particles via hepatic artery.
It generally considered e...
Serous cystadenoma of the pancreas (or 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).
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...
Sickle cell disease (SCD) is an autosomal recessive condition resulting in the formation of abnormal haemoglobin (a haemoglobinopathy), which manifests as multisystem ischaemia and infarction, as well as haemolytic anaemia.
There is no recognised gender predilection. The highest ...
Abdominal manifestations of sickle cell disease (SCD) are wide and can involve many organs.
For a general discussion, please refer to sickle cell disease.
splenic enlargement may occur transiently with the sequestration syndrome, where rapid pooling of blood occurs in th...
Simple hepatic cysts are common benign liver lesions and have no malignant potential. They can be diagnosed on ultrasound, CT, or MRI.
Simple hepatic cysts are one of the commonest liver lesions, occurring in ~2-7% of the population 1-2. There may be a slight female predilection.
The solid abdominal viscera is a collective term for those internal organs of the upper abdomen that are primarily solid in nature, namely the liver, pancreas, spleen, adrenals, and kidneys. It is used in contradistinction to the hollow abdominal viscera, which includes, the stomach, small bowel...
Solid pseudopapillary tumours (SPT) of the pancreas are rare (usually benign) pancreatic tumours.
The tumour has been referred to with multiple different names, including:
solid pseudopapillary tumour (SPT) of the pancreas
solid pseudopapillary neoplasm (SPN)
Somatostatinomas are a rare type of neuroendocrine tumour. They may represent around 1% of all gastro-entero-pancreatic endocrine neoplasms.
Presentation van be variable. Patients with functional stomatostatinomas may present with an "inhibitory syndrome" which is a triad...
Sonographic halo sign is used in a number of situations. They include:
hypoechoic halo sign in liver metastases: used in hepatobiliary imaging, is a concerning feature for malignant lesion if the lesion is a hyperechoic liver lesion 1,2
ultrasound halo in angiolymphoid hyperplasia with eosinop...
Sonographic Murphy sign (SMS) is defined as maximal abdominal tenderness from pressure of the ultrasound probe over the visualised gallbladder 1,2.
SMS is a sign of local inflammation around the gallbladder along with right upper quadrant pain, tenderness or mass 2.
It is one of the most impor...
Spindle cell hepatocellular carcinoma, also called sarcomatoid hepatocellular carcinoma, is a rare variant of hepatocellular carcinoma (HCC). These patients are reported to have low or normal AFP levels, otherwise risk factors and clinical presentation are similar to typical hepatocellular carci...
Splenic abscesses, like abscesses elsewhere, are localised collections of necrotic inflammatory tissue caused by bacterial, parasitic or fungal agents.
Splenic abscesses are uncommon, and their incidence in various autopsy series is estimated at ~0.4% (range 0.14-0.7%) 2,15. The i...
Splenic calcifications can occur is various shapes and forms and can occur from a myriad of aetiological factors.
The usual calcification observed in radiographs are the multiple, miliary form presenting numerous small rounded densities averaging from three to five millimeters in diameter where...
Splenic cysts, although not particularly common, are the most common focal lesion of the spleen. They may be congenital or secondary.
The incidence is ~0.75 per 100,000.
Usually asymptomatic and incidentally discovered at imaging. Left upper quadrant pain and t...
Splenic hamartomas are very rare and usually solitary although may be present as multiple nodules present in tuberous sclerosis or Wiskott-Aldrich syndrome.
The only recently described entity sclerosing angiomatoid nodular transformation (SANT) of the spleen, a non-neoplastic vascular entity de...
Splenic hydatid infection is a rare form of Hydatid disease, and isolated splenic involvement is even less common.
Splenic hydatid disease has been reported to constitute up to 4% of cases of abdominal hydatid disease 4.
Splenic hydatid cysts are usually solitary. As t...
Splenic infarction is a result of ischaemia to the spleen, and in many cases requires no treatment. However, identification of the cause of infarction is essential.
Splenic infarcts can occur due to a number processes, involving either arterial supply, the spleen itself and the ...
Splenic steal syndrome is a possible complication after liver transplantation. In this syndrome, blood flows preferentially from the celiac artery into the splenic artery and the hepatic artery is relatively hypoperfused as a result. This complication can threaten a liver transplant's survival.
Splenomegaly is a term which refers to enlargement of the spleen. The normal adult splenic length upper limit is usually around 12-15 cm.
The causes of splenomegaly are protean, and can be thought of under a number of headings:
A splenorenal shunt refers to an abnormal collateral portosystemic communication between the splenic vein and the left renal vein. It is one of the features of portal hypertension.
Splenosis is one type of ectopic splenic tissue (the other being accessory spleen). It is an acquired condition and is defined as autoimplantation one or more focal deposits of splenic tissue in various compartments of the body.
Abdominal splenosis is seen after abdominal trauma or surgery (e.g...
A "starry sky appearance" refers to a sonographic appearance of the liver parenchyma in which there are bright echogenic dots throughout a background of decreased liver parenchymal echogenicity. Although usually associated with acute hepatitis, this sign has been found to have poor sensitivity a...
Stauffer syndrome is paraneoplastic nephrogenic hepatomegaly. It most commonly occurs in the setting of renal cell carcinoma, and is the enlargement the liver without hepatic metastases. It is a cause of cholestasis and cholestatic jaundice.
History and etymology
It is named after Maurice H. ...
Strawberry gallbladder refers to the surface appearance (not shape) of the mucosa of the gallbladder due to multiple small collections of triglycerides and cholesterol esters within the lamina propria of the gallbladder wall (gallbladder wall cholesterolosis).
Strawberry gallbladder represents...
Subvesical/subvesicular bile ducts are variants of the biliary tree, and knowledge of these are important because they account for a significant portion of post-cholecystectomy bile leaks.
Cholecystohepatic ducts (usually segment V to the gallbladder) are commonly known as bile du...
Supradiaphragmatic liver has been reported as a very rare variant in liver morphology.
In this variant, liver tissue extends into the right hemithorax through an opening in the right hemidiaphragm. The tissue is connected to the right hepatic lobe by a pedicle. In one report, the caudate lobe ...
Syphilis is the result of infection with the gram negative spirochete Treponema pallidum, subspecies pallidum. It results in a heterogeneous spectrum of disease with many systems that can potentially be involved, which are discussed separately.
Despite the discovery of penicillin...
T-tube cholangiograms are a fluroscopic study performed in the setting of hepatobiliary disease. This technique has been largely superseded by MRCP and ERCP.
Typically a T-shaped tube is left in the common bile duct at the time of surgery (e.g. cholecystectomy) and allows for exploration of th...
The target sign of tuberculosis refers to the bull's-eye appearance of some parenchymal tuberculomas involving the brain (see: CNS tuberculosis) and solid abdominal organs (see: hepatic and splenic tuberculosis) on cross-sectional imaging.
hypoechoic nodules ...
The target sign of choledocholithiasis is a finding seen on contrast-enhanced CT and comprises:
central density within the bile duct: stone
surrounding low density: bile or mucosa
Technetium-99m sulfur colloid is one of the technetium radiopharmaceuticals.
photon energy: 140 keV
physical half-life: 6 hours
bone marrow: 5%
target organ: liver, spleen
Tc99m IDA (iminodiacetic acid) analogues are hepatobiliary agents in nuclear medicine, used in cholescintigraphy.
Tc99m-DISIDA: diisopropyl IDA, aka Hepatolite
Tc99m-Mebrofenin: trimethyl bromo IDA, aka Choletec
Tc99m-PIPIDA: paraisopropyl iminodiacetic acid
The use of IDA al...
The tensile gallbladder fundus sign is positive when the gallbladder fundus is seen to bulge into, and distort, the anterior abdominal wall and is a feature of acute cholecystitis.
It is particularly useful as an early sign of the condition on CT as it has around a 75% sensitivity and 95% speci...
Thorotrast is a radioactive radiographic contrast agent containing thorium dioxide first produced in Germany in 1928 and was in use until the 1950s. It was used primarily for cerebral angiography, and 90% of the estimated 50,000-100,000 patients who received it were studied for this purpose.
The three line sign refers to an MRI term that describes the appearance of roundworm Ascaris lumbricoides within the CBD lumen which appears as two hypointense lines representing the worm walls and hyperintense center which represents the worm gut.
TIPS evaluation is useful to ensure that the shunt is working properly and that no stenosis has occurred within the stent. Ultrasound is often used as a first-line modality.
The normal TIPS should show colour Doppler flow throughout its length. The in-stent ve...
The Todani classification of bile duct cysts divides choledochal cysts into five groups.
See: type I choledochal cyst
account for 80-90% of all bile duct cysts
characterised by fusiform dilation of the extrahepatic bile duct
a subclassification has been proposed
Transarterial chemoembolisation therapy (TACE) is a localised method of administrating chemotherapy directly to the liver tumor via a catheter study.
Transarterial embolisation (TAE) (i.e. without a chemotherapy agent added) is also used and there is evidence that this may be just as effective ...
Transient hepatic attenuation differences (THAD) lesions refer to areas of parenchymal enhancement visible during the hepatic artery phase on helical CT. They are thought to be a physiological phenomenon caused by the dual hepatic blood supply. Occasionally they may be associated with hepatic tu...
Transient hepatic intensity differences (THIDs) are a phenomenon observed on MRI imaging of the liver. They are considered a direct equivalent to transient hepatic attenuation differences (THADs) noted on CT. They may be focal or nonfocal.
A focal THID lesion can arise...
Transjugular intrahepatic portosystemic shunt (TIPS) is a treatment for portal hypertension in which direct communication is formed between a hepatic vein and a branch of the portal vein, thus allowing some proportion of portal flow to bypass the liver. The target portosystemic gradient after TI...
The triangular cord sign is a triangular or tubular echogenic cord of fibrous tissue seen in the porta hepatis at ultrasonography and is relatively specific in the diagnosis of biliary atresia1,2.
This sign is useful in the evaluation of infants with cholestatic jaundice, helping for the diffe...
Turtle back sign, also referred as tortoise shell appearance, represents a very characteristic pattern of the schistosomiasis cirrhotic liver in which calcified fibrotic septa are seen aligned perpendicular to the liver capsule resembling the turtle's carapace.
Type I choledochal cysts appear as a fusiform or cystic dilatation of the extrahepatic biliary system (common bile duct +/- common hepatic duct).
Although uncommon in Western countries (1:100,000 to 1:150,000), they are the most common type of biliary cyst. Their prevalence may be...
Ultrasound appearance of liver metastases can have bewildering variation.
Patterns do exist between ultrasound appearance of the liver metastases and the likely primary, which is sometimes helpful in directing a search for an unknown primary, as well as helping distinguish between benign lesion...
Ultrasound guided biopsy is one form of image guided biopsy, typically performed by a radiologist. It is the most common form of image guided biopsy, offering convenience and real time dynamic observation with echogenic markers on cannulae allowing for precise placement.
It can potentially be ...
Ultrasound abdomen is one of the tests that is commonly used in the assessment of patients with abdominal pain. It is particularly useful for the assessment of solid organs and fluid-filled structures.
This is a summary article; we do not have a more in-depth reference articl...
Variation in hepatic arterial anatomy is seen in 40-45% of people. Classic branching of the common hepatic artery from the coeliac artery, and the proper hepatic artery into right and left hepatic arteries to supply the entire liver, is seen in 55-60% of the population.
In general, the common ...
Veins of Sappey are small veins around the falciform ligament that drain the venous blood from the anterior part of the abdominal wall directly into the liver. This flow dilutes the portal perfusion at these sites, causing hepatic pseudolesions.
The superior vein of Sappey drains...
Vicarious contrast material excretion (VCME) defines excretion of water-soluble contrast material in a way other than via normal renal secretion.
The most common vicarious excretion of water-soluble contrast material is via the liver, resulting in increased bile density seen in the gallbladder...
The wall-echo-shadow sign (also known as WES sign) is an ultrasonographic finding within the gallbladder fossa referring to the appearance of a "wall-echo-shadow"
a curvilinear hyperechogenic line representing the gallbladder wall
a thin hypoechoic space representing a small amount of bile
Wandering spleen is a rare condition in which the spleen migrates from its usual anatomical position, commonly to the lower abdomen or pelvis.
Wandering spleen is rare, with a reported incidence of <0.5%.
Diagnosis is most commonly made between ages 20 and 40 and is more common i...
This sign is seen in USG of patient with the hepatic candidiasis and described as central hypoechoic area (necrosis containing fungi) surrounded by an echogenic zone (inflammatory cells).
Differs from bull’s-eye sign for reverse echogeniticity, as it consists a central echogenic nidus surrounde...
Whipple triad is the clinical presentation of pancreatic insulinomas and consists of:
fasting hypoglycemia (<50 mg/dl)
symptoms of hypoglycemia
immediate relief of symptoms after the administration of IV glucose
History and etymology
As a good piece of trivia, one would suspect that Whipple...
Wilson disease, also known as hepatolenticular degeneration, is a rare autosomal recessive disorder of copper metabolism affecting multiple systems.
Wilson disease is commonly found in Japan. It affects 1 in 30,000-40,000 individuals 12.
Hepatobiliary manifestations of Wilson disease vary largely from fatty changes to cirrhosis and occasionally fulminant hepatic necrosis. They result from accumulation of copper in the liver.
For a general discussion of the underlying condition, please refer to the article Wilson disease.
Wirsungocele refers to a cystic dilatation of the pancreatic duct of Wirsung, which is the portion of ventral duct between the dorsal-ventral junction and major duodenal papilla. It is believed to be analogous to choledochocele and santorinicele.
It may be an incidental f...
Xanthogranulomatous cholecystitis is an uncommon inflammatory disease of the gallbladder which may be difficult to differentiate from malignancy, both on imaging and pathologically. It is characterised by presence of multiple intramural nodules.
It is seen predominantly in female ...