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.

52 results found
Article

Bile duct dilatation (differential)

Bile duct dilatation can be due to several aetiologies. Clinical presentation Variable, depending on underlying cause, but usually: right upper quadrant pain jaundice Radiographic features Ultrasound Harmonic imaging is useful when assessing the biliary system, as it improves the clarity ...
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Bile duct wall thickening (differential)

Thickening of the bile duct wall can stem from a variety of aetiologies. Radiographic features Ultrasound bile duct wall thickening bile duct walls are typically not visible when normal possible narrowing of the ducts with obstruction possible secondary signs of cholangitis, including debr...
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Bulging duodenal papilla

Bulging duodenal papilla​ is a conical or cylindrical protuberance at the medial aspect of the descending or horizontal duodenum at the site of the sphincter of Oddi. It is a finding on small bowel follow-though (and endoscopy) and has a relatively long differential. On cross-sectional imaging, ...
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Cholangitis

Cholangitis is a relatively broad descriptive term referring to inflammation of the bile ducts.  It has many forms and can arise from a number of situations: primary sclerosing cholangitis chemotherapy induced cholangitis eosinophilic cholangitis 5 infective cholangitis EBV cholangitis ac...
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Congestive hepatopathy

Congestive hepatopathy includes a spectrum of hepatic derangements that can occur in the setting of right-sided heart failure (and its underlying causes). If there is subsequent hepatic fibrosis the term cardiac cirrhosis may be used. The condition can rarely occur as a result of non-cardiac cau...
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Cystic hepatic metastases

Cystic hepatic metastases are included in the differential for new cystic liver lesions. The internal cystic component may represent necrosis as the tumour outgrows its hepatic blood supply, or it may represent a mucinous component, similar to the primary tumour. The liver and lungs are the mos...
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Cystic lesions of the liver (differential)

Cystic lesions of liver carry a broad differential diagnosis. These include: simple cysts simple hepatic cyst biliary hamartoma Caroli disease adult polycystic liver disease ciliated hepatic foregut duplication cyst 6 infectious: inflammatory conditions hepatic abscess pyogenic hepatic ...
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Cystic lesions of the pancreas (differential)

The differential for cystic lesions of the pancreas includes: unilocular pancreatic pseudocyst intraductal papillary mucinous neoplasm (IPMN) serous cystadenoma uncommonly uni/macrolocular simple pancreatic cyst pancreatic cysts occur in association with  von Hippel Lindau syndrome autos...
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Diffuse gallbladder wall thickening (differential)

Diffuse thickening of the gallbladder wall can occur in a number of situations: cholecystitis acute cholecystitis chronic cholecystitis gallbladder empyema 7 xanthogranulomatous cholecystitis 11 acalculous cholecystitis11 postprandial physiological state (pseudothickening) gallbladder o...
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Exophytic hepatic mass

Exophytic hepatic mass or tumour is a lesion which predominantly lies outside the margins of liver but originates from within the liver. Pathology Causes include 1: benign  hepatic haemangioma hepatic adenoma hepatic cyst hepatic angiomyolipoma focal nodular hyperplasia malignant  hepa...
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Fat containing liver lesions

A variety of benign and malignant liver lesions may contain macroscopic and/or intracytoplasmic fat in sufficient quantities enabling characterisation on imaging studies. Most fat containing liver lesions (80%) in patients with cirrhosis are malignant, most of which are hepatocellular carcinoma ...
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Fetal intrahepatic calcification

Fetal intrahepatic calcification can be a relatively common finding. Calcifications in the liver can be single or multiple and in most cases in which isolated hepatic calcific deposits are detected, there is usually no underlying abnormality. The presence of isolated intrahepatic calcification ...
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Fibropolycystic liver disease

Fibropolycystic liver disease is a collective term for a group of congenital liver and biliary abnormalities resulting from abnormal development of the ductal plates.  Disease in this group include: congenital hepatic fibrosis biliary hamartomas autosomal dominant polycystic disease Caroli d...
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Focal gallbladder wall thickening (differential)

Focal gallbladder wall thickening is an imaging finding that includes both benign and malignant aetiologies. cholecystoses cholesterolosis adenomyomatosis masses gallbladder polyps gallbladder carcinoma: look for infiltration into adjacent organs, metastases, lymphadenopathy, bile duct di...
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Focal gas collection in right upper quadrant (differential)

Focal gas collection in right upper quadrant on plain radiographs can occur from a number of pathologies. Things to consider are: enterobiliary fistula: common types include cholecystoduodenal fistula and cholecystocolic fistula. It may occur with: gallstone ileus (being most common) 3 perfor...
Article

Focal hypodense hepatic lesions on non-enhanced CT (differential)

Focal hypodense hepatic lesions on a non-contrast CT scan can result from a number of pathological entities, including: neoplasms benign hepatic haemangioma adenoma biliary hamartoma: von Meyenberg complexes 2 malignant hepatoma/hepatocellular carcinoma (HCC) hepatic lymphoma hepatic h...
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Gallbladder ghost triad

Gallbladder ghost triad is a term used on ultrasound studies when there is a combination of three gallbladder features on biliary atresia: atretic gallbladder, length less than 19 mm irregular or lobular contour  lack of smooth/complete echogenic mucosal lining with an indistinct wall The te...
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Generalised increase in hepatic echogenicity

Causes of generalised increased liver echogenicity include: diffuse fatty infiltration cirrhosis: can be coarsened as well chronic hepatitis 3: can be coarsened as well diffuse infiltration or deposition malignant process granulomata  tuberculosis brucellosis sarcoidosis glycogen stora...
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Generalised reduced hepatic echogenicity

Causes of generalised reduction of liver echogenicity on ultrasound include: acute hepatitis diffuse malignant infiltration See also generalised increase in liver echogenicity hepatic attenuation on CT
Article

Haemobilia

Haemobilia refers to the presence of blood in the biliary tree. Clinical presentation The classical clinical triad, only seen in ~50% of cases, consists of: melaena (i.e. upper gastrointestinal bleeding) jaundice abdominal pain Pathology Aetiology iatrogenic: surgical or percutaneous pro...
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Hepatic attenuation on CT

Hepatic attenuation on CT, reflected by Hounsfield values, depends on a combination of factors including the presence or absence, as well as the phase, of IV contrast administration. Allowing for all these factors, the mean unenhanced attenuation value is around 55 HU 4. Pathology Several int...
Article

Hepatic vascular and perfusion disorders

Hepatic vascular and perfusion disorders are a broad group of conditions that radiologists should be familiar with, as some of them are quite frequently seen in the daily practice. The aim of this article is to be a collection of articles that represent the core knowledge in the matter. Patholo...
Article

Hepatolithiasis

Hepatolithiasis is the presence of bile duct stones within the intrahepatic bile ducts, specifically before the confluence of the right and left hepatic ducts.  Epidemiology Hepatolithiasis is common Asia and the Pacific, with a prevalence of ~40%. It is rare in the West with a prevalence of ~...
Article

Hepatosplenomegaly

Hepatosplenomegaly is simply the simultaneous presence of a pathologically-enlarged liver (hepatomegaly) and spleen (splenomegaly). Pathology Aetiology Infection Many, many infections can produce a mild concurrent enlargement of the liver and spleen. This list is by no means exhaustive! vir...
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Hypertrophy of the caudate lobe

Hypertrophy of the caudate lobe is seen in a number of conditions, including: cirrhosis: most common Budd-Chiari syndrome primary sclerosing cholangitis (end stage) congenital hepatic fibrosis cavernous transformation of the portal vein Radiographic features The caudate-right lobe ratio m...
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Hypervascular liver lesions

Hypervascular liver lesions may be caused by primary liver pathology or metastatic disease. Differential diagnosis Primary lesions hepatocellular carcinoma (HCC) most common hypervascular primary liver malignancy early arterial phase enhancement and then rapid wash out rim enhancement of c...
Article

Intraductal papillary neoplasm of the bile duct

Intraductal papillary neoplasm of the bile duct (IPNB) is a pre-invasive biliary tree neoplasm considered to be a precursor of cholangiocarcinoma.  Terminology Biliary papillary adenoma and non-invasive papillary carcinoma of the biliary tract were terms used to refer to localised low-grade an...
Article

Intraductal tubulopapillary neoplasm of the bile ducts

Intraductal tubulopapillary neoplasms of the bile ducts are rare intraluminal mass forming pre-invasive biliary neoplasms with no mucin production.  Epidemiology ITPNs of the bile ducts are rare tumours of unknown incidence, found more frequently in women at their 60s 1,2.  Pathology These t...
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Intrahepatic arteriovenous shunt

Intrahepatic arteriovenous shunts, also referred to as intrahepatic arteriovenous malformations (AVMs) or hepatic arteriosystemic venous shunts, represent a spectrum of abnormal communications between the hepatic arterial system and the hepatic veins.  Please note that arterioportal shunts, whi...
Article

Malignant liver tumours (paediatric)

Paediatric malignant liver tumours are rare, some of which occur only in children but that are similar to those that occur in adults. Epidemiology Malignant liver tumours account for ~1% of paediatric malignancies 2. Pathology Broadly, any malignant liver mass can be defined as a metastasis ...
Article

Mass-forming intrahepatic cholangiocarcinoma

Mass-forming intrahepatic cholangiocarcinomas (MF-ICC), also referred as peripheral cholangiocarcinomas, compromise one of the three recognised growth patterns of intrahepatic cholangiocarcinomas.  On imaging, these tumours usually present as large and relatively well-defined hepatic masses wit...
Article

Medical devices in the abdomen and pelvis

Medical devices in the abdomen and pelvis are important to be recognised, just like medical devices of the chest. Often we ignore these devices, considering them to be incidental and non-pathological, however it is essential to be aware of potential complications. Gastrointestinal tubes stomac...
Article

Mucinous cystic neoplasm of the gallbladder

Mucinous cystic neoplasms of the gallbladder are extremely rare epithelial cystic tumours formed by mucin-producing cells. They are histologically similar to the other mucinous cystic tumours found elsewhere in the body. For the lesions involving the bile ducts, please refer to: biliary cystad...
Article

Non-neoplastic solid lesions of the pancreas

Non-neoplastic solid lesions of the pancreas are conditions which may mimic pancreatic neoplasms on imaging. They include: focal pancreatitis autoimmune pancreatitis fatty infiltration-replacement intrapancreatic accessory spleen peripancreatic lymph node congenital anomalies prominent pa...
Article

Pancreatic atrophy

Pancreatic atrophy is non-specific and is common in elderly patients, although in younger patients it can be a hallmark of pathology. Most commonly it is associated with ageing, obesity and end-stage chronic pancreatitis.  It occurs principally with fatty replacement of the pancreas (pancreatic...
Article

Pancreatic calcifications

Pancreatic calcifications can arise from many aetiologies. 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 ​...
Article

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...
Article

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 oedematous pancreatitis necrotising pan...
Article

Periampullary tumours

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

Periportal hyperechogenicity

Periportal hyperechogenicity can result from many causes including: pneumobilia cholecystitis schistosomiasis of the portal region recurrent pyogenic cholangitis (oriental) inflammatory bowel disease: has been described to give "echo-rich" periportal cuffing 2​
Article

Periportal hypoechogenicity

Periportal hypoechogenicity can result from many causes: orthotopic liver transplant rejection congestive hepatomegaly malignant lymphatic obstruction cholangitis viral hepatitis See also periportal hyperechogenicity periportal halo
Article

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...
Article

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...
Article

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 spilt into the peritoneal cavity. Clinical presentation Many cases of dropped gallstones will be a...
Article

Sclerosing cholangitis

There are three forms of sclerosing cholangitis: primary sclerosing cholangitis IgG4-related sclerosing cholangitis secondary sclerosing cholangitis
Article

Splenic abscess

Splenic abscesses, like abscesses elsewhere, are localised 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...
Article

Splenic calcification

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 millimetres in diameter where...
Article

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...
Article

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...
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

Transient hepatic attenuation differences

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...
Article

Ultrasound appearances of liver metastases

Ultrasound appearance of liver metastases can have bewildering variation, and the presence of hepatic steatosis can affect the sonographic appearance of liver lesions. Radiographic features Ultrasound Patterns do exist between ultrasound appearance of the liver metastases and the likely prima...

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