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.

44 results found
Article

Fluid-fluid levels in liver lesions

Fluid-fluid levels in liver lesions are a rare appearance of both benign and malignant conditions. Differential diagnosis benign complicated hepatic cyst 2 hepatic abscess 2 chronic hepatic hematoma 3 biliary cystadenoma 3 hepatic hemangioma (very rare) 2 malignant cystic/necrotic hepat...
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Periportal lymphadenopathy (differential)

Periportal lymphadenopathy can be a common observation during imaging of the upper abdomen. What is considered the exact upper limit of normal has been variable 1,3 among different publications but with many authors suggesting a cut-off of around 10 mm in short axis diameter. Pathology Etiolog...
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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

Hepatosplenomegaly

Hepatosplenomegaly is simply the simultaneous presence of a pathologically-enlarged liver (hepatomegaly) and spleen (splenomegaly). Pathology Etiology Infection Many infections can produce a mild concurrent enlargement of the liver and spleen. This list is by no means exhaustive. viral EBV...
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Gallbladder cancer

Gallbladder cancer is relatively uncommon compared to other hepatobiliary malignancies. Pathology Primary gallbladder carcinoma gallbladder adenocarcinoma: most common 1 gallbladder squamous cell carcinoma gallbladder neuroendocrine carcinoma gallbladder sarcoma: very rare 2 gallbladder ...
Article

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...
Article

Cirrhosis (pulmonary manifestations)

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 acute respiratory distress syndr...
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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 aging, obesity and end-stage chronic pancreatitis.  It occurs principally with fatty replacement of the pancreas (pancreatic ...
Article

Bile duct wall thickening (differential)

Thickening of the bile duct wall can stem from a variety of etiologies. 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 debri...
Article

Bile duct dilatation

Bile duct dilatation refers to the dilatation of intrahepatic or extrahepatic bile ducts. Clinical presentation Variable, depending on the underlying cause, but usually: right upper quadrant pain jaundice Radiographic features Ultrasound Harmonic imaging is useful when assessing the bilia...
Article

Focal gallbladder wall thickening (differential)

Focal gallbladder wall thickening is an imaging finding that includes both benign and malignant etiologies. cholecystoses cholesterolosis adenomyomatosis masses gallbladder polyps gallbladder carcinoma: look for infiltration into adjacent organs, metastases, lymphadenopathy, bile duct dil...
Article

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 tumor outgrows its hepatic blood supply, or it may represent a mucinous component, similar to the primary tumor. The liver and lungs are the most ...
Article

Cystic lesions of the liver (differential)

Cystic lesions of the liver carry a broad differential diagnosis: 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 abscess am...
Article

Pseudocirrhosis

Pseudocirrhosis is a radiological term used to convey the imaging findings of cirrhosis, but emphasize that it occurs in the setting of hepatic metastases. It is most commonly reported following chemotherapeutic treatment of breast cancer metastases, although has also been reported before treatm...
Article

Exophytic hepatic mass

Exophytic hepatic mass or tumor is a lesion which predominantly lies outside the margins of liver but originates from within the liver. Pathology Causes include 1: benign  hepatic hemangioma hepatic adenoma hepatic cyst hepatic angiomyolipoma focal nodular hyperplasia malignant  hepati...
Article

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...
Article

Hepatic capsular retraction

Hepatic capsular retraction is an uncommon finding that is defined as loss of the normal liver contour due to focal flattening/irregularity or concavity. It is related to several benign and malignant pathologies. Differential diagnosis The list of differential diagnoses associated with hepatic...
Article

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...
Article

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...
Article

Coarsened hepatic echotexture

Coarsened hepatic echotexture is a sonographic descriptor used when the uniform smooth hepatic echotexture of the liver is lost. This can occur due to a number of reasons which include: conditions that cause hepatic fibrosis 1 cirrhosis hemochromatosis various types of hepatitis 3 particula...
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, etiological agent or associated pathology. acute pancreatitis interstitial edematous pancreatitis necrotizing panc...
Article

Fat containing liver lesions

Fat containing liver lesions represent a variety of benign and malignant liver lesions may contain macroscopic and/or intracytoplasmic fat in sufficient quantities enabling characterization on imaging studies. Most fat-containing liver lesions (80%) in patients with cirrhosis are malignant, most...
Article

Medical devices in the abdomen and pelvis

Medical devices in the abdomen and pelvis are important to be recognized, just like medical devices of the chest. We often ignore these devices, considering them to be incidental and non-pathological, however it is essential to be aware of potential complications. Gastrointestinal devices tube...
Article

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 ...
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 hepatopathy malignant lymphatic obstruction cholangitis viral hepatitis See also periportal hyperechogenicity periportal halo
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 spilled into the peritoneal cavity. Clinical presentation Many cases of dropped gallstones will be...
Article

Hemobilia

Hemobilia refers to the presence of blood in the biliary tree. Clinical presentation The classical clinical triad, only seen in ~50% of cases, consists of: melena (i.e. upper gastrointestinal bleeding) jaundice abdominal pain Pathology Etiology iatrogenic: surgical or percutaneous proced...
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 hemangioma adenoma biliary hamartoma: von Meyenberg complexes 2 malignant hepatoma/hepatocellular carcinoma (HCC) hepatic lymphoma hepatic ha...
Article

Generalized increase in hepatic echogenicity

Causes of generalized increase in hepatic echogenicity include: diffuse fatty change cirrhosis: and/or coarsening chronic hepatitis 3: and/or coarsening diffuse infiltration or deposition malignant process granulomata  tuberculosis brucellosis sarcoidosis glycogen storage disease hemo...
Article

Generalized reduced hepatic echogenicity

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

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, ...
Article

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

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 cholecystitis 11 postprandial physiological state (pseudothickening) gallbladder ...
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 t...
Article

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...
Article

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

Ultrasound appearances of hepatic metastases

Ultrasound appearance of hepatic 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 hepatic metastases and the likely p...
Article

Splenomegaly

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

Splenic cyst

Splenic epithelial cysts, also known 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 (~80%)...
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 (commonly known as pancreatic cancer) 90-95%  cyst...
Article

Hypervascular liver lesions

Hypervascular liver lesions are findings that enhance more or similarly to the background hepatic parenchyma in the late arterial phase, on contrast-enhanced CT or MRI. Differential diagnosis Primary lesions hepatocellular carcinoma (HCC) most common hypervascular primary liver malignancy e...
Article

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 cystic neuroendocrine tumor of the pancreas diffuse pancreatic cysts pancrea...

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