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.

587 results found
Article

Primary hyperoxaluria

Primary hyperoxaluria, also referred as primary oxalosis, is a congenital autosomal recessive disease related to a liver enzyme deficiency leading to massive cortical nephrocalcinosis and renal failure.  Please, refer on secondary oxalosis for a discussion on the acquired form of hyperoxaluria....
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Primary myelofibrosis

Primary myelofibrosis is a myeloproliferative neoplasm in which there is the replacement of bone marrow with collagenous connective tissue and progressive fibrosis. It is characterized by: extramedullary hematopoiesis progressive splenomegaly anemia variable change in the number of granulocy...
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Primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is an uncommon inflammatory condition, which affects the biliary tree resulting in multiple strictures, liver damage, and eventually cirrhosis. The diagnosis can be made when there are classical imaging features in the correct clinical context, and secondary...
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Prolonged heterogeneous liver enhancement (CEUS)

Prolonged heterogeneous liver enhancement (PHLE), also informally termed as the "disappearing liver" phenomenon, is a very rare, benign complication of ultrasound contrast media, of currently unknown etiology 1. PHLE manifests itself as confluent, rapidly appearing hyperechoic foci in the liver,...
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Pseudocalculus sign (common bile duct)

The pseudocalculus sign is a term coined to describe a mimic of a distally impacted common bile duct (CBD) stone on ERCP, MRCP and the various forms of cholangiography, including T-tube, CT, intraoperative, and percutaneous 1. It results from the forceful contraction of the choledochal sphincte...
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Pseudocirrhosis

Pseudocirrhosis is a radiological term used to recapitulate imaging findings of cirrhosis, but occurring in the setting of hepatic metastases. It is most commonly reported following chemotherapeutic treatment of breast cancer metastases, although has also been reported before treatment, and with...
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Pseudocyst

A pseudocyst is an abnormal fluid-filled cavity which is not lined by epithelium.  It is this fact that distinguishes it pathologically from a cyst, which is lined by epithelium. Examples of pseudocysts include: adrenal pseudocyst auricular pseudocyst meconium pseudocyst pancreatic pseudocy...
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Pseudogallbladder sign

Pseudogallbladder sign is a sonographic feature that can be seen in some children with biliary atresia. Radiographic features Ultrasound Appears as a cystic structure seen in the liver which is confused with gallbladder in a few cases of biliary atresia. In these patients it is an important f...
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Pseudolipoma of the Glisson capsule

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. Radiographic features CT well-circumscribed fat attenuation (-20 to -70 HU) nodule at the liver surface MRI well-circumscri...
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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...
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Puestow procedure

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...
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Pulmonary complications of cirrhosis

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) intrathoracic portosystemic collateral vessel formation The development of portal hypert...
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Pulsatile portal venous flow

A pulsatile portal venous flow pattern can result from both physiological and pathological causes. In well subjects mild pulsatility, or in rare situations, even marked pulsatility has been described, particularly in thin subjects, with a venous pulsatility index of >0.5 with an inverse correla...
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Pylephlebitis

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 the portal venous system. Clinical Presentation Clinical presentation is often vague. Patients may initially present with...
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Radiation-induced liver disease

Radiation-induced liver disease (RILD), also referred to as radiation hepatitis, represents the toxic effect of radiation therapy on normal hepatocytes.   This article will discuss liver toxicity appearances after external beam radiotherapy techniques. Please refer to the dedicated article on s...
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Radioembolization

Radioembolization is the delivery of radioactive microspheres to cancers using an endovascular approach. It is often performed as an outpatient procedure.  Indications hepatocellular carcinoma hepatic metastases from colorectal carcinoma Contraindications Absolute contraindications excessi...
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Recurrent pyogenic cholangiohepatitis

Recurrent pyogenic cholangiohepatitis, previously known as oriental cholangiohepatitis, is a condition most commonly found in patients residing in or immigrated from Southeast Asia and is characterized by intra and extrahepatic bile duct strictures and dilatation with an intraductal pigmented st...
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Regenerative liver nodule

Regenerative liver nodules are a form of non-neoplastic nodules that arise in a cirrhotic liver. Terminology This may be slightly different from the term nodular regenerative hyperplasia, which are described histopathologically as regenerative nodules with little or no hepatic fibrosis and lar...
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Retained gallstone

Retained gallstones, also called dropped or slipped gallstones, are common during a laparoscopic cholecystectomy, with a reported incidence of 0.1–20%, and occur when gallstones are inadvertently spilled into the peritoneal cavity. Clinical presentation Many cases of dropped gallstones will be...
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Reticuloendothelial system

The reticuloendothelial system (RES) comprises a number of tissues: spleen bone marrow liver Kupffer cells
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Reverse target sign (cirrhotic nodules)

A reverse target sign is a potential ultrasound marker for cirrhotic nodules on ultrasound.It represents central iso-hyperechogenicity with surrounding hyperechoic rim. This sign is useful to differentiate metastases from cirrhotic nodules, conversely the target sign is seen with liver metastases.
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Revised Atlanta classification of acute pancreatitis

The Revised Atlanta classification of acute pancreatitis from 2012 is an international multidisciplinary classification of the severity of acute pancreatitis, updating the 1992 Atlanta classification. The worldwide consensus aims for an internationally agreed-upon classification of acute pancre...
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Rhabdomyosarcomas (biliary tract)

Rhabdomyosarcomas of the biliary tract are rare tumors, usually identified in children, with a very poor prognosis. They are usually grouped under botryoid rhabdomyosarcomas. For a general discussion of this type of tumor, please refer to the article on rhabdomyosarcomas. Epidemiology Rhabdom...
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Riedel lobe

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 pelv...
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Right hepatic artery

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. Gross anatomy The proper hepatic artery bifurcates into the right and left hepatic arteries at or before rea...
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Right posterior hepatic notch sign

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...
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Right subphrenic space

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. Gross anatomy This is a subcompartment of the supracolic compartment. It reaches as far as the up...
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Right triangular ligament of the liver

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.
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Rigler triad (gallstone ileus)

Rigler triad consists of three findings seen in gallstone ileus: pneumobilia 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. Practical points Rigler triad should not ...
Article

Rokitansky-Aschoff sinuses

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. Related pathology They are not of themselves considered abnormal, but may be ass...
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Rolling stone sign

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...
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Rosary sign (gallbladder)

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.
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Round belly sign (abdominal compartment syndrome)

Round belly sign is a sign of increased abdominal pressure in abdominal compartment syndrome where the abdomen has a rounded appearance of transverse section on CT, rather than its typical oval shape. The sign is positive when the AP to transverse diameter of the abdomen (abdominal ratio) is > ...
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Saber sign (pneumobilia)

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...
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Santorinicele

A santorinicele 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 choledochocele 3.  It usually occurs in association with pancreas divi...
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Sarcoidosis (abdominal manifestations)

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 less common than pulmonary and mediastinal disease, abdominal sarcoidosis can mimic more common infectious or neoplast...
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Schistosomiasis

Schistosomiasis (also referred to as bilharzia or snail fever) is the result of infection by blood fluke (trematode worm) of the Schistosoma species. Epidemiology Schistosomiasis is very common, affecting over 200 million people, with the vast majority (85%) in Africa. It is prevalent in tropi...
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Schistosomiasis (hepatic manifestations)

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.  Clinical presentation U...
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Scleroderma

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 pulmona...
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Scleroderma (hepatobiliary manifestations)

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...
Article

Sclerosing cholangitis

There are three forms of sclerosing cholangitis: primary sclerosing cholangitis IgG4-related sclerosing cholangitis secondary sclerosing cholangitis
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Secondary hepatic involvement with lymphoma

Secondary hepatic involvement with lymphoma (secondary hepatic lymphoma) is common, much more so than primary hepatic lymphoma.  Clinical presentation Hepatomegaly with deranged liver function tests is the most common presentation. Jaundice is common. Rarely, patients may present with acute li...
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Secondary sclerosing cholangitis

Secondary sclerosing cholangitis refers to manifestations of sclerosing cholangitis that resemble primary sclerosing cholangitis but can be attributed to known insults to the biliary tree. Pathology Secondary sclerosing cholangitis is a chronic cholestatic disease. The entity is characterized ...
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Selective internal radiation therapy

Selective internal radiation therapy (SIRT), also know as hepatic radioembolization, is a relatively new and developing modality for treating non-resectable liver tumors. The procedure consists of a transcatheter injection of radioactive particles via the hepatic artery.  It is generally consid...
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Selenium toxicity

Selenium toxicity (rarely: hyperselenemia) is caused by excessive intake of the non-metallic element selenium (Se) in the diet. Epidemiology It is less common than selenium deficiency. It is most frequently seen in some parts of India, in which there are naturally high levels of selenium in th...
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Serous cystadenoma of pancreas

Serous cystadenoma of the pancreas, also referred as microcystic adenoma, is an uncommon type of benign cystic pancreatic neoplasm.  Epidemiology There is a recognized strong female predilection (M:F ~ 1:4) and usually presents in middle age to elderly patients (>60 years of age).  Clinical p...
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Serpent sign

The serpent sign, or snake sign, is described in hydatid disease. The WHO classification (2001) or Gharbi classification (1985) of the hydatid disease describe several stages on ultrasound 1. During the active stage, the cyst is composed of three layers: the outer (pericyst), the middle (ectocys...
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Serum ascites albumin gradient

The serum–ascites albumin gradient (SAAG) is the difference between the concurrently obtained serum albumin concentration and the albumin concentration of the ascitic fluid obtained during paracentesis.  Pathology A difference ≥1.1 grams/deciliter (g/dL) indicates portal hypertension as the li...
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Seurat spleen

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. Pathology Several mechanisms are thought to to attribute to this appearance which include sinusoidal s...
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Sickle cell disease

Sickle cell disease (SCD) (historically known as drepanocytosis) is a hereditary (autosomal recessive) condition resulting in the formation of abnormal hemoglobin (a hemoglobinopathy), which manifests as multisystem ischemia and infarction, as well as hemolytic anemia.  Hemoglobin SC (HbSC) dis...
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Sickle cell disease (abdominal manifestations)

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 splenomegaly may occur transiently with the sequestration syndrome, where rapid pooling of blood occurs in the spleen, resulting ...
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Simple hepatic cyst

Simple hepatic cysts are common benign liver lesions and have no malignant potential. They can be diagnosed with ultrasound, CT, or MRI. Epidemiology 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...
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Sinistral portal hypertension

Sinistral portal hypertension (also known as left-sided portal hypertension or segmental portal hypertension) is an uncommon form of portal hypertension. Clinical presentation Sinistral portal hypertension is most commonly found incidentally in asymptomatic patients. In symptomatic patients, t...
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Solid and hollow abdominal viscera

The solid abdominal viscera (singular: viscus) 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 s...
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Solid pseudopapillary tumor of the pancreas

Solid pseudopapillary tumors (SPT) of the pancreas are rare (usually benign) pancreatic tumors. Terminology The tumor has been referred to with multiple different names, including: solid pseudopapillary tumor (SPT) of the pancreas solid pseudopapillary neoplasm (SPN) solid pseudopapillary e...
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Somatostatinoma

Somatostatinomas are a rare type of neuroendocrine tumor. They may represent around 1% of all gastro-entero-pancreatic endocrine neoplasms. Clinical presentation The presentation can be variable. Patients with functional somatostatinoma may present with an "inhibitory syndrome" which is a tria...
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Sonographic halo sign

Sonographic halo sign is used in a number of situations. They include: hypoechoic halo sign (also known as target or bull's eye 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...
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Sonographic Murphy sign

Sonographic Murphy sign is defined as maximal abdominal tenderness from pressure of the ultrasound probe over the visualized gallbladder 1,2. It is a sign of local inflammation around the gallbladder along with right upper quadrant pain, tenderness and/or a mass 2. It is one of the most importa...
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Spectral Doppler (ultrasound)

Utilizing automated Fourier analysis to convert returning sound waves into a series of individual frequencies, spectral Doppler refers to ultrasound modalities which yield graphical representations of flow velocity over time.  Terminology The frequency of the sound waves returned to an ultraso...
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Sphincter of Oddi

The sphincter of Oddi (also known as the sphincter of ampulla or choledochal sphincter) is a complex of four smooth muscle sphincters within the duodenal wall. It surrounds, and helps fix to the duodenum, the duct of Wirsung, common bile duct and the ampulla of Vater 1,2.  When relaxed it allow...
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Sphincter of Oddi dysfunction

Sphincter of Oddi dysfunction is a functional disorder in which stenosis or dyskinesia of the sphincter of Oddi obstructs drainage from the common bile duct. Epidemiology The disorder is associated with history of cholecystectomy, in which case it is also called postcholecystectomy syndrome. T...
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Spider web appearance

Spider web appearance is a classic appearance seen on venography in a patient with hepatic venous outflow obstruction. It refers to the dense network of hepatic venous collaterals seen. 
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Spindle cell hepatocellular carcinoma

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...
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Splenic abscess

Splenic abscesses, like abscesses elsewhere, are localized collections of necrotic inflammatory tissue caused by bacterial, parasitic or fungal agents. They uncommonly affect the spleen due to its efficient reticuloendothelial system phagocytic activity and, consequently, are more likely seen in...
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Splenic artery aneurysm

Splenic artery aneuryms are the commonest visceral arterial aneurysm formation as well as the 3rd commonest abdominal aneurysm (after the aorta and iliac vessels). Aneurysms are usually saccular in configuration and they can either be in the form of a true aneurysm (much more common) or as a pse...
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Splenic brucellosis

Brucellosis is a common zoonosis, which is particularly prevalent in Mediterranean countries. It produces a multisystemic illness that can present with a broad spectrum of clinical manifestations and complications 1. This article is focusing on the splenic involvement by brucellosis. For genera...
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Splenic calcification

Splenic calcifications can occur is various shapes and forms and can occur from a myriad of etiological 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 ...
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Splenic cyst

Splenic epithelial cysts, also referred as splenic epidermoid cysts or primary splenic cysts, are unilocular fluid lesions with thin and smooth walls and no enhancement. They represent ~20% of cysts found in the spleen, and are usually an innocuous incidental imaging finding. Note that most (~8...
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Splenic hamartoma

Splenic hamartomas are very rare lesions commonly found incidentally on imaging. They are most often solitary but may be present as multiple nodules in patients with tuberous sclerosis or Wiskott-Aldrich syndrome. Terminology  The recently-described sclerosing angiomatoid nodular transformatio...
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Splenic hydatid infection

Splenic hydatid infection is a rare form of hydatid disease, and isolated splenic involvement is even less common. For a general discussion, and for links to other system-specific manifestations, please refer to the article on hydatid disease.  Epidemiology Splenic hydatid disease has been re...
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Splenic infarction

Splenic infarction is a result of ischemia to the spleen, and in many cases requires no treatment. However, identification of the cause of infarction is essential.   Epidemiology Splenic infarcts can occur due to a number of processes, involving either arterial supply, the spleen itself or the...
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Splenic peliosis

Splenic peliosis is an unusual benign disorder characterized by the presence of irregular cystic blood-filled cavities. Clinical presentation Most patients are asymptomatic although very rarely patient can present with spontaneous organ rupture. Associations Recognized associations include ...
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Splenic steal syndrome

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. ...
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Splenomegaly

Splenomegaly refers to enlargement of the spleen. The upper limit of normal adult splenic length is traditionally cited at 12 cm, but lengths upwards of 14 cm can be seen in normal, taller males 7. Massive splenomegaly is variably defined, including when the spleen is 5 standard deviations abov...
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Splenorenal shunt

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. See also portosystemic shunts
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Splenosis

Splenosis is one type of ectopic splenic tissue (the other being accessory spleen). It is an acquired condition and is defined as autoimplantation of one or more focal deposits of splenic tissue in various compartments of the body. Abdominal splenosis is seen after abdominal trauma or surgery (...
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Starry sky appearance (disambiguation)

Starry sky appearance is a radiological sign used to describe the appearance of the liver on two different imaging modalities: starry sky appearance (ultrasound) Starry sky appearance (MRI)
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Starry sky appearance (MRI)

Starry sky appearance on MRI refers to the appearance of small innumerable T2 hyperintense multiple bile duct hamartomas and biliary microhamartomas, scattered throughout the T2 hypointense hepatic parenchyma, which resembles a “starry sky”. The high T2 lesions are representing Von Meyenburg com...
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Starry sky appearance (ultrasound)

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 and...
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Stauffer syndrome

Stauffer syndrome is paraneoplastic nephrogenic hepatomegaly. It most commonly occurs in the setting of renal cell carcinoma, and is the enlargement of the liver without hepatic metastases. It is a cause of cholestasis and cholestatic jaundice.  History and etymology It is named after Maurice ...
Article

Strawberry gallbladder

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...
Article

Subvesical bile ducts

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.  Terminology Cholecystohepatic ducts (usually segment V to the gallbladder) are commonly known as bile du...
Article

Superior pancreaticoduodenal artery

The superior pancreaticoduodenal artery is a branch of gastroduodenal artery that supplies the duodenum and pancreas. Gross anatomy Superior pancreaticoduodenal artery arises after branching off from gastroduodenal artery. It divides into anterior and posterior divisions which supply the pylor...
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Supradiaphragmatic liver

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 ...
Article

Syphilis

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.  Epidemiology Despite the discovery of penicillin...
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Target sign (choledocholithiasis)

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
Article

Target sign (tuberculosis)

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.  Radiographic features Ultrasound hypoechoic nodules ...
Article

Tc99m IDA (iminodiacetic acid) analogs

Tc99m IDA (iminodiacetic acid) analogs are hepatobiliary agents in nuclear medicine, used in cholescintigraphy. These include: Tc99m-DISIDA: diisopropyl IDA, aka Hepatolite Tc99m-Mebrofenin: trimethyl bromo IDA, aka Choletec Tc99m-PIPIDA: paraisopropyl iminodiacetic acid The use of IDA alon...
Article

Tc-99m sulfur colloid

Technetium-99m sulfur colloid is one of the technetium radiopharmaceuticals. Characteristics photon energy: 140 keV physical half-life: 6 hours biological half-life normal distribution: liver: 85% spleen: 10% bone marrow: 5% excretion: hepatic target organ: liver, spleen pharmacokinet...
Article

Technetium agents

Technetium agents based on the technetium-99m (Tc-99m) radioisotope are frequently used agents in medical imaging. A radiopharmaceutical labeled with 99mTc constitutes a coordination complex in which ligands bond to a central atom of 99mTc by coordinate covalent bonds 4 . The radioactive techne...
Article

Tensile gallbladder fundus sign

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...
Article

Third inflow

Third inflow refers to anatomical variants leading to an additional venous inflow to the liver apart from the usual dual blood supply (portal vein and hepatic artery). They tend to be associated with parenchymal pseudolesions (focal hyperenhancement on post-contrast imaging, focal fat infiltrati...
Article

Thorotrast

Thorotrast is a suspension of radioactive thorium dioxide first produced in Germany in 1928 and used as a contrast agent until the 1950s. Its principal use was for cerebral angiography: 90% of the estimated 50,000-100,000 patients treated received it for this purpose. Umbrathor was another thori...

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